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Head gasket
#1
O
Oarhead
O
Oarhead
I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#2
S
slomo
S
slomo
1.Have you thought about lapping the head and block face where the gasket goes?
2.Torquing and retorquing the head bolts a few times after the job is done?
3.Cleaning the bolt holes out with a bottom tap?
4.Cleaning the bolt threads off with a die?
5.Spraying a little high tack sealant on the gasket prior to installing?
You know, doing the job proper?
2.Torquing and retorquing the head bolts a few times after the job is done?
3.Cleaning the bolt holes out with a bottom tap?
4.Cleaning the bolt threads off with a die?
5.Spraying a little high tack sealant on the gasket prior to installing?
You know, doing the job proper?
#3
O
Oarhead
O
Oarhead
I've actually done all of the above. Soooo....yea ....proper...along with an engine degrease and power wash. Same spot on ggasket.
#5
StarTech
StarTech
Now I am assume 18.5 single cylinder here.
Are you torquing in the sequence shown in the service manual use three step torque procedure to 21 ft/lbs. Service manual has it 220 in-lbs / 18.3 ft/lbs but Brigg increased it to 250 in-lbs / 20.8 (IE 21 ft-lbs) due head gasket failures.
Are you torquing in the sequence shown in the service manual use three step torque procedure to 21 ft/lbs. Service manual has it 220 in-lbs / 18.3 ft/lbs but Brigg increased it to 250 in-lbs / 20.8 (IE 21 ft-lbs) due head gasket failures.
#6
F
Forest#2
F
Forest#2
How long does a head gasket usually last on your engine? (average time, like one hour, one day, or a year???)
The head and or block is either warped or as startech indicates you are not torqueing the head bolts PROPERLY.
With patience you should be able to check the head and block for warpage.
Also if it has a small dip or groove in the aluminum where it is burning through is not a good thing.
That area you describe is a wimpy place for the single cylinder Briggs Intek engines, some last forever, some don't and proceed by the book (service manual) when replacing the head gasket on those type. Make sure all the cooling fins and flywheel plastic fins are in place. Do not test run the engine over few seconds with the cooling shroud removed.
If all else fails try two heads gaskets.
The head and or block is either warped or as startech indicates you are not torqueing the head bolts PROPERLY.
With patience you should be able to check the head and block for warpage.
Also if it has a small dip or groove in the aluminum where it is burning through is not a good thing.
That area you describe is a wimpy place for the single cylinder Briggs Intek engines, some last forever, some don't and proceed by the book (service manual) when replacing the head gasket on those type. Make sure all the cooling fins and flywheel plastic fins are in place. Do not test run the engine over few seconds with the cooling shroud removed.
If all else fails try two heads gaskets.
#7
S
slomo
S
slomo
He's already done all these items.How long does a head gasket usually last on your engine? (average time, like one hour, one day, or a year???)
The head and or block is either warped or as startech indicates you are not torqueing the head bolts PROPERLY.
With patience you should be able to check the head and block for warpage.
Also if it has a small dip or groove in the aluminum where it is burning through is not a good thing.
That area you describe is a wimpy place for the single cylinder Briggs Intek engines, some last forever, some don't and proceed by the book (service manual) when replacing the head gasket on those type. Make sure all the cooling fins and flywheel plastic fins are in place. Do not test run the engine over few seconds with the cooling shroud removed.
If all else fails try two heads gaskets.
#8
S
slomo
S
slomo
Every Briggs head I've removed is not flat. Not even close. Engine block face the same. Once a year I clean the cooling fins and change the oil. Check torque on the head bolts. Always find a couple or more that will turn a bit.
#9
F
Forest#2
F
Forest#2
He also asked:
Are these engines junk?
Post up the engine ID info for a more precise Yes or No.
Are these engines junk?
Post up the engine ID info for a more precise Yes or No.
#11
O
Ocean909
O
Ocean909
Are these OEM gaskets? I know its tempting to buy the aftermarket considering the price
#12
sgkent
sgkent
checking the head and block for straightness with a machinists straight edge should be done anytime there is a blown head gasket. If the old one was solid and the head and piston were just decarbonized, then there would not be a need for it, but with a blown head gasket there is often something warped.
#13
B
bertsmobile1
B
bertsmobile1
Go to CopperGasketsUS.
Speak to Lanni ( wonderful bloke )
Get one of his full copper head gaskets
Problem solved
Once fitted make sure you put an in line fuel tap and that you use it
The head gaskets are deliberately weak so that in the case of a hydro lock the gasket blows rather then bending a rod or cracking the head .
Fairly sure he does a stock line of various intek head gaskets .
Speak to Lanni ( wonderful bloke )
Get one of his full copper head gaskets
Problem solved
Once fitted make sure you put an in line fuel tap and that you use it
The head gaskets are deliberately weak so that in the case of a hydro lock the gasket blows rather then bending a rod or cracking the head .
Fairly sure he does a stock line of various intek head gaskets .
#15
sgkent
sgkent
we aren't using ether to start it are we?
#17
O
Ocean909
O
Ocean909
Had no idea this existed. His gaskets are only a bit more than current OEM prices. Thanks for this.Go to CopperGasketsUS.
Speak to Lanni ( wonderful bloke )
Get one of his full copper head gaskets
Problem solved
Once fitted make sure you put an in line fuel tap and that you use it
The head gaskets are deliberately weak so that in the case of a hydro lock the gasket blows rather then bending a rod or cracking the head .
Fairly sure he does a stock line of various intek head gaskets .
#18
B
bertsmobile1
B
bertsmobile1
Told you Lanni was a nice guy
I get a lot of custom gaskets cut by him for antique motorcycles because it is actually cheaper than buying sheet copper & cutting them myself
They usually need to be annealed but some have arrived full soft
The rule of thumb is to roll your thumb nail over an edge pressing down hard
If it leaves a full crescent impression then the gasket is soft enough to use without annealing .
If it solves your problem please come back at the end of the season to let us know
I get a lot of custom gaskets cut by him for antique motorcycles because it is actually cheaper than buying sheet copper & cutting them myself
They usually need to be annealed but some have arrived full soft
The rule of thumb is to roll your thumb nail over an edge pressing down hard
If it leaves a full crescent impression then the gasket is soft enough to use without annealing .
If it solves your problem please come back at the end of the season to let us know
#19
M
melvin1942
M
melvin1942
Remove the head, take a straight edge Across both head and block. Use a feeler gauge and see if you and put it between the straight edge and the head and also between straight efce and block.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#20
C
Curtisun
What I do is first take emery cloth and a flat block and emery the head and block clean of all discoloration, then I put on the new head with new bolts. I torque to specifications twice. This gives it max torque on the bolts. Torque bolts in the specified order. If this does not stop it from blowing head gaskets you will have to have the head and block resurfaced.
C
Curtisun
Replace the head bolts is one of the main things. Once a bolt has been torqued it changes the metal and can cause them to lessen the torque when the engine gets hot.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
What I do is first take emery cloth and a flat block and emery the head and block clean of all discoloration, then I put on the new head with new bolts. I torque to specifications twice. This gives it max torque on the bolts. Torque bolts in the specified order. If this does not stop it from blowing head gaskets you will have to have the head and block resurfaced.
#21
C
Cajun power
C
Cajun power
if you have PROFESSIONALLY FACED the upper cylinder head and main block? (I'm skeptical...not saying you did not do it...but there is a world of difference between DIY truing and professional).
so if you removed to much material, it may be difficult to actually get valve clearance set...no matter what you must reset valve clearance. PER THE SERVICE MANUAL...Lot of bad information out on the interwebs., And check that valve seats have not stepped out...makes sure the exhaust and intake valve are not borked with soot or heat damage like warp ...also look at exhaust ports...something soot gets cooked and that can cause overheat.
the gaskets you bought may be the wrong type. (for instance...on some mower engines the OEM gaskets have been improved and superceded with better materials...usually a composite, metal/fiber type. you will need to research this...there is alot of junk resellers out there who send wrong parts and not the upgraded parts...recheck everything.
your engine might be running way too lean...this overheat cycle over and over is going to eventually blow out head gaskets. Try to look for any air leaks and adjust the carb spot on.
the mayb be serious internal damage to oil pressure pump...if yours has one. most of the cheaper have slingers...some have an actual oil pump. If oil is not getting where it needs to go, overheat...head gaskets blow out. (and hopefully, only that!)
the cylinder head may be cracked. Sometimes it a very small micro crack that only creates problems after hot cycle. If you suspect this, you can either do a penetrant dye and black light inspection...or shadetree: do a hot cycle, shut mower off and as soon as you can set up and perform a leak down check...the latter might be able to
other causes could be head gasket bolts that have stretched or bolt threads in the head are borked. It's one of those things that can happen from improper torque but also getting slammed by overheat cycles over and over.
if you've done all these things and everything checks out..AND THE LEAK DOWN CHECK IS GOOD AND GOOD COMPRESSION then consider buying COPPER GASKETS...They are superior in almost every way...better squish, and far superior heat transfer. Here is an reputable company that I have recently bought copper gaskets to fit a kawasaki mower engine I rebuilt..
coppergaskets.us
so if you removed to much material, it may be difficult to actually get valve clearance set...no matter what you must reset valve clearance. PER THE SERVICE MANUAL...Lot of bad information out on the interwebs., And check that valve seats have not stepped out...makes sure the exhaust and intake valve are not borked with soot or heat damage like warp ...also look at exhaust ports...something soot gets cooked and that can cause overheat.
the gaskets you bought may be the wrong type. (for instance...on some mower engines the OEM gaskets have been improved and superceded with better materials...usually a composite, metal/fiber type. you will need to research this...there is alot of junk resellers out there who send wrong parts and not the upgraded parts...recheck everything.
your engine might be running way too lean...this overheat cycle over and over is going to eventually blow out head gaskets. Try to look for any air leaks and adjust the carb spot on.
the mayb be serious internal damage to oil pressure pump...if yours has one. most of the cheaper have slingers...some have an actual oil pump. If oil is not getting where it needs to go, overheat...head gaskets blow out. (and hopefully, only that!)
the cylinder head may be cracked. Sometimes it a very small micro crack that only creates problems after hot cycle. If you suspect this, you can either do a penetrant dye and black light inspection...or shadetree: do a hot cycle, shut mower off and as soon as you can set up and perform a leak down check...the latter might be able to
other causes could be head gasket bolts that have stretched or bolt threads in the head are borked. It's one of those things that can happen from improper torque but also getting slammed by overheat cycles over and over.
if you've done all these things and everything checks out..AND THE LEAK DOWN CHECK IS GOOD AND GOOD COMPRESSION then consider buying COPPER GASKETS...They are superior in almost every way...better squish, and far superior heat transfer. Here is an reputable company that I have recently bought copper gaskets to fit a kawasaki mower engine I rebuilt..
KAWASAKI 11004-7026,FS730V,FX651V, FX69V, FX730V,LAWNMOWERS,9C3
Made in USA Thickness .016" solid copper Bore 3.110" Reusable if not damaged SHIPS FOR FREE USA ONLY INTERNATIONAL SHIPPING $13
coppergaskets.us
#22
O
Oarhead
O
Oarhead
33r777 for this one. Definetly headgasket. Gonna have head milled and do a close check on the block. I also have 33r877, changed everything,(springtime maintenence), fuel filters etc. Starts when choked but dies when throttle to fast run. Ugh...He also asked:
Are these engines junk?
Post up the engine ID info for a more precise Yes or No.
#23
O
Oarhead
O
Oarhead
Gonna pay closer attn to the surfaces. Thoughts on copper gaskets?How long does a head gasket usually last on your engine? (average time, like one hour, one day, or a year???)
The head and or block is either warped or as startech indicates you are not torqueing the head bolts PROPERLY.
With patience you should be able to check the head and block for warpage.
Also if it has a small dip or groove in the aluminum where it is burning through is not a good thing.
That area you describe is a wimpy place for the single cylinder Briggs Intek engines, some last forever, some don't and proceed by the book (service manual) when replacing the head gasket on those type. Make sure all the cooling fins and flywheel plastic fins are in place. Do not test run the engine over few seconds with the cooling shroud removed.
If all else fails try two heads gaskets.
#24
sgkent
sgkent
is the head worth milling cost wise? I use a machinists straight edge and check it I I I then three spots 90 degrees from that then an X. If it is good then milling it will only raise compression and make any overheating and compression worse. Compare the cost vs new. Best guess is that a machine shop will just lay it flat on a good quality band sander and surface it that way. One does a couple light X patterns with it to keep it even. I can't imagine trying to hold a mower head down on a real head and block milling machine. I used to run a Vulcan mill for that and no way would I trust a small mower head not to go flying if I tried to MILL it.
#25
G
grpascott
G
grpascott
I had trouble with my 18.5hp intek blowing head gasket too. The head bolts were lousy alloy and kept stretching, so I replaced them with grade 8 bolts. This required adding some additional thread length with a die as the bolts weren't threaded deep enough, but the extra work was worth it. It's been several years now...no blown head gaskets. (Torque to 22 ft lbs.)I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#26
S
slomo
S
slomo
These only have like 10-20ft lbs depending on engine.Replace the head bolts is one of the main things. Once a bolt has been torqued it changes the metal and can cause them to lessen the torque when the engine gets hot.
#27
S
slomo
S
slomo
It's not the space shuttle guys (Taryl). Little 220, 400 and 800 grit paper and a piece of plate glass for the block. Also use the side garage door window to lap the head. Cheap sanding block, what ever........ Get her done.
#28
G
GrumpyCat
G
GrumpyCat
That test will tell you if it is bad but will not be an assurance that it is good. Sure, it is straight from corner to corner but are the corners in the same plane square to the stroke?Remove the head, take a straight edge Across both head and block. Use a feeler gauge and see if you and put it between the straight edge and the head and also between straight efce and block.
#30
B
bertsmobile1
If you think 20 ftlbs into alloy is going to cause any structural change to a bolt, even a grade 3 bolt then you must have been asleep during your science classes at high school or gone to a school that teaches creationism and languages with no science at all .
When torquing down into alloy you damage the hole not the steel bolt which is why quality alloy engines use inserts , to protect the block.
On bolts
Higher tensile bolts have deeper cut threads so there is more surface area of metal to metal contact to create more friction between the bolt & the hole which is why the bolt stays in there and why using a grade 9 bolt seems to hold better, nothing to do with the tensile strength of the steel.
Please try not to conflate automative technology with mower technology where there is almost none .
B
bertsmobile1
This is only true for CAST IRON engine blocks where the head bolts are done up to 100 ftlbs of torque or there abouts .Replace the head bolts is one of the main things. Once a bolt has been torqued it changes the metal and can cause them to lessen the torque when the engine gets hot.
What I do is first take emery cloth and a flat block and emery the head and block clean of all discoloration, then I put on the new head with new bolts. I torque to specifications twice. This gives it max torque on the bolts. Torque bolts in the specified order. If this does not stop it from blowing head gaskets you will have to have the head and block resurfaced.
If you think 20 ftlbs into alloy is going to cause any structural change to a bolt, even a grade 3 bolt then you must have been asleep during your science classes at high school or gone to a school that teaches creationism and languages with no science at all .
When torquing down into alloy you damage the hole not the steel bolt which is why quality alloy engines use inserts , to protect the block.
On bolts
Higher tensile bolts have deeper cut threads so there is more surface area of metal to metal contact to create more friction between the bolt & the hole which is why the bolt stays in there and why using a grade 9 bolt seems to hold better, nothing to do with the tensile strength of the steel.
Please try not to conflate automative technology with mower technology where there is almost none .
#31
B
bertsmobile1
Warping is done corner to corner and is very rare on a mower head
Erosion is quite common because the gasket starts to leak and the movement of gas , particularly burning gas erodes the metal from both the head & the block, exactly the same way a river erodes a valley or canyon.
On Inteks the bridge region between the push rod tunnel & cylinder is where it usually erodes.
Then we come to thread pulling
Run a short strait edge across all of the holes in the block
Usually you fund the metal has raised slightly at the edge of the holes
This happens because there is a tiny annulus of the block that has no support when the pressure is applied because the head gaskets are not a tight fit on the engine bolts .
The head can do the same thing but usually the hole just collapses onto the bolt which is why some times the head bolts will not pull out easily.
Using a thick large diameter washer avoids this because it spreads the load over a larger area and thus only the shear plane is massively larger .
For those who have tried to flatten an intek head and block the first thing you will notice is while it is flat, it is not smooth and on the first couple of strokes you reveal the tooling swirls from the fly cutter used to machine them at the factory.
Do not try to remove them completely they are there to prevent the gasket from walking under pressure
Now we come to torque
People will argue to the ends of earth weather they should be 21 ft lbs or 22 ft lbs etc etc etc
It does not make a wrinkled rats rectum of difference
Anything from around 15 ft lbs to 30 ft lbs is fine
15 is where the clamping force is no longer enough to hold the surfaces tight enough to resist the gas pressure during combustion .
30 is approaching the yield strength of the alloy threads in that diameter bolt .
What is vital which all the Face Book experts fail to appreciate is that ALL THE TORQUES ARE IDENTICAL.
This is why B & S Started to use in lbs in place of the usual ft lbs
when they say 240 in lbs that is 240 +/- 0.5 in lbs so they expect you to do those bolts up to within 1 in lb of each other .
This implied accuracy is what every one fails to understand
a tension wrench marked in in lbs only will be a lot more accurate than one marked in ft lbs only and thus a lot more expensive
If they specified 20 ft lbs again that is +/- 0.5 ft lb with is 12 in lbs and no where near as accurate or in this case consistent and consistency is why you are shooting for for not absolute accuracy .
and when it come to accuracy, very few torque wrenches under $ 100 will be accurate and of those that are they only read true over a limited temperature range and micrometer adjusted ones go out of calibration very quickly even if you back them all off past zero every time you have finished using them because the internal coil spring collapses with use , same as your car suspension springs sag or valve springs shorten over time .
Next we come to the actual tightening
the more steps the better ( within reason ) so torquing them in 3 or 4 steps will always yield a better result then hand tight then final torque .
Finally a full copper head gasket has copper all the way from the cylinder to the outside world
a std B & S gasket has nothing more than the very thin fire ring ( if that ) to hold back the combustion gasses .
Once that is breached then you have a composite layered joining board and that does not have the structural integrity to stop leaking between the layers
So go with Lanni's full copper gasket & it will be a last time you have to do the job, if you do it properly
FWIW I use a1/2" drill bit hand held to cut a tiny champher around all the bolt holes
B
bertsmobile1
The head is tested for warping , erosion & thread pulling .Remove the head, take a straight edge Across both head and block. Use a feeler gauge and see if you and put it between the straight edge and the head and also between straight efce and block.
Warping is done corner to corner and is very rare on a mower head
Erosion is quite common because the gasket starts to leak and the movement of gas , particularly burning gas erodes the metal from both the head & the block, exactly the same way a river erodes a valley or canyon.
On Inteks the bridge region between the push rod tunnel & cylinder is where it usually erodes.
Then we come to thread pulling
Run a short strait edge across all of the holes in the block
Usually you fund the metal has raised slightly at the edge of the holes
This happens because there is a tiny annulus of the block that has no support when the pressure is applied because the head gaskets are not a tight fit on the engine bolts .
The head can do the same thing but usually the hole just collapses onto the bolt which is why some times the head bolts will not pull out easily.
Using a thick large diameter washer avoids this because it spreads the load over a larger area and thus only the shear plane is massively larger .
For those who have tried to flatten an intek head and block the first thing you will notice is while it is flat, it is not smooth and on the first couple of strokes you reveal the tooling swirls from the fly cutter used to machine them at the factory.
Do not try to remove them completely they are there to prevent the gasket from walking under pressure
Now we come to torque
People will argue to the ends of earth weather they should be 21 ft lbs or 22 ft lbs etc etc etc
It does not make a wrinkled rats rectum of difference
Anything from around 15 ft lbs to 30 ft lbs is fine
15 is where the clamping force is no longer enough to hold the surfaces tight enough to resist the gas pressure during combustion .
30 is approaching the yield strength of the alloy threads in that diameter bolt .
What is vital which all the Face Book experts fail to appreciate is that ALL THE TORQUES ARE IDENTICAL.
This is why B & S Started to use in lbs in place of the usual ft lbs
when they say 240 in lbs that is 240 +/- 0.5 in lbs so they expect you to do those bolts up to within 1 in lb of each other .
This implied accuracy is what every one fails to understand
a tension wrench marked in in lbs only will be a lot more accurate than one marked in ft lbs only and thus a lot more expensive
If they specified 20 ft lbs again that is +/- 0.5 ft lb with is 12 in lbs and no where near as accurate or in this case consistent and consistency is why you are shooting for for not absolute accuracy .
and when it come to accuracy, very few torque wrenches under $ 100 will be accurate and of those that are they only read true over a limited temperature range and micrometer adjusted ones go out of calibration very quickly even if you back them all off past zero every time you have finished using them because the internal coil spring collapses with use , same as your car suspension springs sag or valve springs shorten over time .
Next we come to the actual tightening
the more steps the better ( within reason ) so torquing them in 3 or 4 steps will always yield a better result then hand tight then final torque .
Finally a full copper head gasket has copper all the way from the cylinder to the outside world
a std B & S gasket has nothing more than the very thin fire ring ( if that ) to hold back the combustion gasses .
Once that is breached then you have a composite layered joining board and that does not have the structural integrity to stop leaking between the layers
So go with Lanni's full copper gasket & it will be a last time you have to do the job, if you do it properly
FWIW I use a1/2" drill bit hand held to cut a tiny champher around all the bolt holes
#32
H
Honest Abe
H
Honest Abe
how to check your head bolts to see if they've been over torqued. Take a regular nut the size of your bolt and try spinning it onto the bolt. If it goes on without and real resistance then go ahead and reuse it/them. If you have to use any amount of force to get it on then toss that bolt . . .
#33
S
slomo
S
slomo
What about any dirt, rust or any other contaminant on the threads? You must have a huge bucket of perfectly good bolts you toss out LOL.how to check your head bolts to see if they've been over torqued. Take a regular nut the size of your bolt and try spinning it onto the bolt. If it goes on without and real resistance then go ahead and reuse it/them. If you have to use any amount of force to get it on then toss that bolt . . .
#34
H
Honest Abe
H
Honest Abe
if the bolt has rust on the inside threads you've got more of a problem than just a head gasket. If you're sticking a head bolt with rust on it back into the head then I dang sure don't want you working on any of my stuff ( . ) . . . . . .What about any dirt, rust or any other contaminant on the threads? You must have a huge bucket of perfectly good bolts you toss out LOL.
#35
S
slomo
I agree, don't have me working on your mowers. No argument there.
S
slomo
For sure. I'm ordering all new bolts for all my mowers for every day of the week. Might get a snip of contamination on them while mowing.if the bolt has rust on the inside threads you've got more of a problem than just a head gasket. If you're sticking a head bolt with rust on it back into the head then I dang sure don't want you working on any of my stuff ( . ) . . . . . .
I agree, don't have me working on your mowers. No argument there.
#36
B
bertsmobile1
Abe is right, the thread can deform but they usually neck at the junction between the thread & the shank before the threads actually deform because the threads are constrained by the thread of what ever they are threaded into.
If you have a nut & bolt situation then over torquing will cause a deformation to the actual thread.
And this can be felt by running a CLOSE FITTING nut along the bolt
To a lesser extent this also works for through bolts like a B & S head bolt
But will not work for a bolt into a blind hole like most head bolts are .
In this case you measure the length of the bolt before & after .
Precision bolts are often ground at the end to be exactly the same length so you can detect a thou or two of elongation but B & S bolts are not precision they are standard roll forged domestic grade bolts and if you care to measure then you will find the lengths are all over the place and impossible to measure accurately because there is a rim around the end of the shank .
So again while technically correct this is something that does apply to automotive engines but is irrelevant to mower engines .
B
bertsmobile1
Keep it civil fellasFor sure. I'm ordering all new bolts for all my mowers for every day of the week. Might get a snip of contamination on them while mowing.
I agree, don't have me working on your mowers. No argument there.
Abe is right, the thread can deform but they usually neck at the junction between the thread & the shank before the threads actually deform because the threads are constrained by the thread of what ever they are threaded into.
If you have a nut & bolt situation then over torquing will cause a deformation to the actual thread.
And this can be felt by running a CLOSE FITTING nut along the bolt
To a lesser extent this also works for through bolts like a B & S head bolt
But will not work for a bolt into a blind hole like most head bolts are .
In this case you measure the length of the bolt before & after .
Precision bolts are often ground at the end to be exactly the same length so you can detect a thou or two of elongation but B & S bolts are not precision they are standard roll forged domestic grade bolts and if you care to measure then you will find the lengths are all over the place and impossible to measure accurately because there is a rim around the end of the shank .
So again while technically correct this is something that does apply to automotive engines but is irrelevant to mower engines .
#37
T
tank1949
T
tank1949
I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....Slomo is correct, but you should have first did a compression test after the rebuild. If the head or block is warped, u may have to discard it, since the machine shop expenses to flatten parts will not justify keeping it. .
#38
H
Honest Abe
I would respectfully disagree; because, if there's rust on the "threads" then there's no doubt rust on the threads in the hole. Unless you run a tap into the hole and clean off the hole threads and blow the debris out as well then you run the risk of not accurately tightening the bolt(s). This is just my take, not saying I've ever seen it more than a bunch of times . . . . . .
H
Honest Abe
".....this is something that does apply to automotive engines but is irrelevant to mower engines."Keep it civil fellas
Abe is right, the thread can deform but they usually neck at the junction between the thread & the shank before the threads actually deform because the threads are constrained by the thread of what ever they are threaded into.
If you have a nut & bolt situation then over torquing will cause a deformation to the actual thread.
And this can be felt by running a CLOSE FITTING nut along the bolt
To a lesser extent this also works for through bolts like a B & S head bolt
But will not work for a bolt into a blind hole like most head bolts are .
In this case you measure the length of the bolt before & after .
Precision bolts are often ground at the end to be exactly the same length so you can detect a thou or two of elongation but B & S bolts are not precision they are standard roll forged domestic grade bolts and if you care to measure then you will find the lengths are all over the place and impossible to measure accurately because there is a rim around the end of the shank .
So again while technically correct this is something that does apply to automotive engines but is irrelevant to mower engines .
I would respectfully disagree; because, if there's rust on the "threads" then there's no doubt rust on the threads in the hole. Unless you run a tap into the hole and clean off the hole threads and blow the debris out as well then you run the risk of not accurately tightening the bolt(s). This is just my take, not saying I've ever seen it more than a bunch of times . . . . . .
#39
B
bertsmobile1
B
bertsmobile1
Point is that there is zero chance of stretching a steel bolt in an aluminium casting, it just can not happen
Bolt stretch when tightening into a cast iron block can happen but not into an alloy block tensioned to 20 ft lbs
That sort of torque is not even in the elastic deformation range.
Nothing wrong with the nut test for thread deformation except it is not applicable to mower engines .
And yes threads should be clean and dry but that should be a given .
Bolt stretch when tightening into a cast iron block can happen but not into an alloy block tensioned to 20 ft lbs
That sort of torque is not even in the elastic deformation range.
Nothing wrong with the nut test for thread deformation except it is not applicable to mower engines .
And yes threads should be clean and dry but that should be a given .
#40
B
Big Al O
B
Big Al O
Make sure the muffler & exhaust are not restrictedI have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#41
K
kenv52
K
kenv52
I have a zero turn with a Briggs intek 18.5. I also have a friend that worked for a country clipper distributor for years. I’ve put two on mine so far. He said that engine is known for blowing head gaskets and that a lot of dealers would refuse shipment if it had that engine. It runs fine other than that. He even told me where it blows at and sure enough he was right. It did it two times. It then leaks compression into the block and blows oil out the vent/breather thing on the side of the motor. It’s important to re torque the head bolts after a mow or two after installation. I’ve been thinking about just buying another head gasket kit and having it on handI have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#42
G
Gord Baker
G
Gord Baker
Certain belt sanders have wide adhesive backed grit. Attach a long length to a FLAT piece of Steel and sand ead, rotating it often. Check with light and straight edge.
Ditto with flat piece of steel to Block. Are you using OEM gaskets. Torque and sequence are very important.
Perhaps try with copper anti-seize applied sparingly to both sides of gasket. Good luck. Check Crank for partially sheared key. Incorrect timing could cause excessive temps and pressure perhaps.
Ditto with flat piece of steel to Block. Are you using OEM gaskets. Torque and sequence are very important.
Perhaps try with copper anti-seize applied sparingly to both sides of gasket. Good luck. Check Crank for partially sheared key. Incorrect timing could cause excessive temps and pressure perhaps.
#43
Moparjoe499
Moparjoe499
Get a concrete block, lay the block down and take the head and rub it on the concrete block a couple times. Look at it and you will see where the low spot is. Keep rubbing it until the low spot disappears. I have done this before and it works.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#44
Piros1
Piros1
Sounds as you are skilled at engine repair but I will throw something out I did not see mentioned. Did you clean both head and block surfaces and check with a good straight edge to be sure they are flat and not damaged or pitted?
#46
Roy405
Roy405
I'd have to think something is not flat.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#47
C
Curtisun
I had a 4-wheeler with aluminum block, 650 cc that keep blowing head gaskets after a few hours of running. I made sure there was no cracks or warpage. Come to find out after I finally found a manual on it and after 5 head gasket replacements it stated, "Head bolts must be replaced when head is removed for any reason". It did not give a reason. I purchase all new head bolts and it has been running for about a year now with no problems.
C
Curtisun
Then I ask why it specifically says to replace head bolts in manuals for aluminum block and heads.This is only true for CAST IRON engine blocks where the head bolts are done up to 100 ftlbs of torque or there abouts .
If you think 20 ftlbs into alloy is going to cause any structural change to a bolt, even a grade 3 bolt then you must have been asleep during your science classes at high school or gone to a school that teaches creationism and languages with no science at all .
When torquing down into alloy you damage the hole not the steel bolt which is why quality alloy engines use inserts , to protect the block.
On bolts
Higher tensile bolts have deeper cut threads so there is more surface area of metal to metal contact to create more friction between the bolt & the hole which is why the bolt stays in there and why using a grade 9 bolt seems to hold better, nothing to do with the tensile strength of the steel.
Please try not to conflate automative technology with mower technology where there is almost none .
I had a 4-wheeler with aluminum block, 650 cc that keep blowing head gaskets after a few hours of running. I made sure there was no cracks or warpage. Come to find out after I finally found a manual on it and after 5 head gasket replacements it stated, "Head bolts must be replaced when head is removed for any reason". It did not give a reason. I purchase all new head bolts and it has been running for about a year now with no problems.
#48
J
Joed756
J
Joed756
If you have done all of this already, try using two head gaskets. Often that will make up for any head deformities.
#49
L
lofty66
L
lofty66
Almost certainly a warped head, but some of the methods being suggested here to flatten it are a good way to ruin a perfectly good head. Do not use sand paper or concrete both are far to coarse and inaccurate. The best way is to use fine valve grinding paste on a piece of glass, preferably 1/4" or thicker as that's flatter. Do not use a scrap double glazed panel as they're often slightly concave. oil the glass, then smear on some fine valve grinding paste. Place the head on it and move in a figure of eight motion, every dozen or so figures of eight stop, turn the head through 90 degrees and continue. Every so often lift up the head and check the lapped surface, low spots will be obvious. Continue, adding more grinding paste as necessary, until the whole surface is an even mat colour. Wash off, then refit using a new head gasket and torque down gradually, ie bring the bolts up together, do not torque down one fully then the next and so on. If the order is not known tightening diagonally is a good rule of thumb.
One other thing to check is to make sure the bolts (or one possibly) aren't bottoming out too early. Without the head try fitting them, and make sure when fully inserted the gaps between the block and the head of the bolt are all less than the thickness of the head. If they are bottoming out, even when torqued down they won't be squeezing the gasket correctly.
One other thing to check is to make sure the bolts (or one possibly) aren't bottoming out too early. Without the head try fitting them, and make sure when fully inserted the gaps between the block and the head of the bolt are all less than the thickness of the head. If they are bottoming out, even when torqued down they won't be squeezing the gasket correctly.
#50
G
G5200
G
G5200
Had this problem with a 21 HP B&S about 15 years ago. The key that positions the flywheel (and magneto) relative to the crank (times the spark) had partially sheared, causing the spark plug to fire too early. Preignition - overpressurized the cylinder and kept blowing out head gaskets. Check your TDC vs when the cams move the valves.
#51
B
barny57
B
barny57
Head can’t be flat , even 1 not torqued bolt wouldn’t cause thatI have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#52
J
joea99
It happened when doing a head gasket replacement, doing the first bolt with a bad clicker torque wrench that had "worked last time". Since it was my first Subaru overhaul and I was following a script, it did not dawn on me, till too late, that I was WAY beyond where is should have clicked. Short story is that after redoing the torque sequence with a new wrench, I was not confident of a good job and pulled the head.
Yep, that bolt was clearly stretched very badly. I was concerned about having deformed or pulled the threads, but after checking the block and the bolt holes, got a new gasket and new bolts and finished the job. My own car, so not sorry at all, except for the expense.
J
joea99
I have personally stretched a brand new steel head bolt in an aluminum block. Granted, it was an automotive engine (a Subaru) and the ultimate torque was far over 20 ft lbs, but it IS an aluminum block.Point is that there is zero chance of stretching a steel bolt in an aluminium casting, it just can not happen
Bolt stretch when tightening into a cast iron block can happen but not into an alloy block tensioned to 20 ft lbs
That sort of torque is not even in the elastic deformation range.
Nothing wrong with the nut test for thread deformation except it is not applicable to mower engines .
And yes threads should be clean and dry but that should be a given .
It happened when doing a head gasket replacement, doing the first bolt with a bad clicker torque wrench that had "worked last time". Since it was my first Subaru overhaul and I was following a script, it did not dawn on me, till too late, that I was WAY beyond where is should have clicked. Short story is that after redoing the torque sequence with a new wrench, I was not confident of a good job and pulled the head.
Yep, that bolt was clearly stretched very badly. I was concerned about having deformed or pulled the threads, but after checking the block and the bolt holes, got a new gasket and new bolts and finished the job. My own car, so not sorry at all, except for the expense.
#53
T
TobyU
T
TobyU
Well, if you did all that then something wasn't done right or something is atypical and even though you're doing what you're supposed to be doing you're not getting the results and it's letting the procedure fail.
I have red posts over the past 10 years or so about people who have had more than one head gasket failure and it always astounds me because I have done a lot of these Briggs & Stratton 31xxxx and 33xxxx and I have literally never had a repeat failure!!
Maybe I'm just lucky but I don't think that's the case.
At bare minimum the head needs to be scraped clean with a razor blades scraper or putty knife or whatever and white clean with brake cleaner or carb cleaner or whatever and a rag and the same for the block surface. That's the bare minimum.
Then it is a must that you use the proper head bolt torquing sequence which has been revised and an accurate inch pound torque wrench.
Maybe you're rich is off one way or the other??
I want snapped a rod bolt on a 12-point headed Buick 455 engine because I borrowed a torque wrench when I was a teenager and didn't own one myself and it was calibrated way off! It must have been 25 to 30 lb minimum off because it snapped that off and I had to go to the junkyard to get another one..
So that's all I ever do and I never have failures but if I'm trying to prevent a failure I will go two extra steps..
I will place it on a flat piece of glass or very flat metal with some 60 or 80 grit sandpaper taped down..
Then I will send the heck out of it until the entire surface is even.
This of course isn't as good as actually milling one but you will quickly see the high spots and then as you keep going you're saying will start to hit the other spots so you know you have it much more flat than when you started.
It takes a long time and gets annoying. The last time I counted I had to do at least 500 strokes before I even got close to being smooth and acceptable.
Also, I do it in all different directions as I rotate it a quarter turn throughout the process multiple times.
Then the second thing I will do is spray the permatex copper spray gasket on both sides of the gasket.
Like I said I rarely do either of these and they still last for years after I put them together so I'm very surprised you're having repeated problems.
Are you using the Briggs & Stratton gaskets or the ones you get on eBay and amazon?
In this case the ones that are aftermarket could very well be better than the briggs one because it is junk from beginning and they sell you a same junk when to replace it.
I believe I saw a couple online that seemed to look like they had a fire ring around the combustion chamber which would be an improvement.
When Kohler had this problem back in the early 2000s they recalled all of their original head gaskets and replaced it with a head gasket kit, while expensive, it was a much improved head gasket much beefier and with a fire ring around it so the problem would not reoccur.
Briggs does nothing!
I have red posts over the past 10 years or so about people who have had more than one head gasket failure and it always astounds me because I have done a lot of these Briggs & Stratton 31xxxx and 33xxxx and I have literally never had a repeat failure!!
Maybe I'm just lucky but I don't think that's the case.
At bare minimum the head needs to be scraped clean with a razor blades scraper or putty knife or whatever and white clean with brake cleaner or carb cleaner or whatever and a rag and the same for the block surface. That's the bare minimum.
Then it is a must that you use the proper head bolt torquing sequence which has been revised and an accurate inch pound torque wrench.
Maybe you're rich is off one way or the other??
I want snapped a rod bolt on a 12-point headed Buick 455 engine because I borrowed a torque wrench when I was a teenager and didn't own one myself and it was calibrated way off! It must have been 25 to 30 lb minimum off because it snapped that off and I had to go to the junkyard to get another one..
So that's all I ever do and I never have failures but if I'm trying to prevent a failure I will go two extra steps..
I will place it on a flat piece of glass or very flat metal with some 60 or 80 grit sandpaper taped down..
Then I will send the heck out of it until the entire surface is even.
This of course isn't as good as actually milling one but you will quickly see the high spots and then as you keep going you're saying will start to hit the other spots so you know you have it much more flat than when you started.
It takes a long time and gets annoying. The last time I counted I had to do at least 500 strokes before I even got close to being smooth and acceptable.
Also, I do it in all different directions as I rotate it a quarter turn throughout the process multiple times.
Then the second thing I will do is spray the permatex copper spray gasket on both sides of the gasket.
Like I said I rarely do either of these and they still last for years after I put them together so I'm very surprised you're having repeated problems.
Are you using the Briggs & Stratton gaskets or the ones you get on eBay and amazon?
In this case the ones that are aftermarket could very well be better than the briggs one because it is junk from beginning and they sell you a same junk when to replace it.
I believe I saw a couple online that seemed to look like they had a fire ring around the combustion chamber which would be an improvement.
When Kohler had this problem back in the early 2000s they recalled all of their original head gaskets and replaced it with a head gasket kit, while expensive, it was a much improved head gasket much beefier and with a fire ring around it so the problem would not reoccur.
Briggs does nothing!
#54
C
charleneje
C
charleneje
If that is true about headbolts not stretching why do all automobile manufacturers in the workshop manual say to replace all headbolts on aluminum heads and even on some other uses where aluminum parts are used. I remember back in the 1960's that when taking the head of an all aluminum engine Hillman Imp you stood a good chance of breaking headbolts when taking the head of the engine to do a decoke something very few engines nowadays. I know that is about automotive but it proves the point about bolts stretching I believe.
#55
T
Tommy Mckeown
T
Tommy Mckeown
Well, the same spot would indicate that either the block, the head, or both are not true. I think you need to get a precision straight edge and check that area on both surfaces. A Starrett brand will be about $100 while an Amazon one will be $30. One is accurate to .0003". while the other is .001 You are just checking not machining so the $30 one should be just fine.
#56
reynoldston
reynoldston
I use a flat pace countertop and cover it with sandpaper. I start with 100 grit and work up to 600. I sand the head surface and engine. Then retorque head bolts to specs starting with a low setting and working up to the full setting. I have never had a gasket problem doing it this way. Also when removing the head you need to do that in the proper sequence also.
#57
C
charleneje
I did the repair thanks to advice from others on this forum Like you I was ready to just replace my few years old mower now my only problem is the rear automatic axle/gearbox makes noise and slips but I cant get it off with my equipment to check it out so I will wait for it to quit then replace the mower.
C
charleneje
I had the same problems on a 22hp Briggs engine I would replace the head gasket and it kept on blowing after just a short amount of use, I came on here and was suggested to make sure the head was flat by testing with a straight edge and using a piece of glass and sanding it I got some 240 grit sandpaper and spray glue and stuck the paper to a sheet of thick glass I have it took a long time but i used a figure eight sanding pattern and it finally got flat in every direction I checked also when sanding a head you can see all the highs and lows because of the sandpaper marks. I ordered a head gasket from CopperGasketsUS. having discussed my problem with Lanni and he sent me an already annealed head gasket, so I made sure everything was cleaned properly and sprayed Permatex copper spray gasket on both sides of the gasket and on the head and cylinder assembled and torqued the head according to manual I then left it for two days everything covered with a big rag and then retorqued the head bolts, put everything together and haven't had any problem's since I do have a fuel shut off on the mower because fuel will leak past the carb and fill the crankcase. I check my oil before each use and not long after I first got the mower the oil was right up the dipstick and it smelled of gas hence the fuel shutoff.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
I did the repair thanks to advice from others on this forum Like you I was ready to just replace my few years old mower now my only problem is the rear automatic axle/gearbox makes noise and slips but I cant get it off with my equipment to check it out so I will wait for it to quit then replace the mower.
#58
T
TobyU
T
TobyU
Well, if you did all that then something wasn't done right or something is atypical and even though you're doing what you're supposed to be doing you're not getting the results and it's letting the procedure fail.
I have red posts over the past 10 years or so about people who have had more than one head gasket failure and it always astounds me because I have done a lot of these Briggs & Stratton 31xxxx and 33xxxx and I have literally never had a repeat failure!!
Maybe I'm just lucky but I don't think that's the case.
At bare minimum the head needs to be scraped clean with a razor blades scraper or putty knife or whatever and white clean with brake cleaner or carb cleaner or whatever and a rag and the same for the block surface. That's the bare minimum.
Then it is a must that you use the proper head bolt torquing sequence which has been revised and an accurate inch pound torque wrench.
Maybe you're rich is off one way or the other??
I want snapped a rod bolt on a 12-point headed Buick 455 engine because I borrowed a torque wrench when I was a teenager and didn't own one myself and it was calibrated way off! It must have been 25 to 30 lb minimum off because it snapped that off and I had to go to the junkyard to get another one..
So that's all I ever do and I never have failures but if I'm trying to prevent a failure I will go two extra steps..
I will place it on a flat piece of glass or very flat metal with some 60 or 80 grit sandpaper taped down..
Then I will send the heck out of it until the entire surface is even.
This of course isn't as good as actually milling one but you will quickly see the high spots and then as you keep going you're saying will start to hit the other spots so you know you have it much more flat than when you started.
It takes a long time and gets annoying. The last time I counted I had to do at least 500 strokes before I even got close to being smooth and acceptable.
Also, I do it in all different directions as I rotate it a quarter turn throughout the process multiple times.
Then the second thing I will do is spray the permatex copper spray gasket on both sides of the gasket.
Like I said I rarely do either of these and they still last for years after I put them together so I'm very surprised you're having repeated problems.
Are you using the Briggs & Stratton gaskets or the ones you get on eBay and amazon?
In this case the ones that are aftermarket could very well be better than the brakes one because it is junk from beginning and they sell you a same junk when to replace it.
I believe I saw a couple online that seemed to look like they had a fire ring around the combustion chamber which would be an improvement.
When Kohler had this problem back in the early 2000s they recalled all of their original head gaskets and replaced it with a head gasket kit, while
Head bolts in the old days up until the late '80s were never TTY torque to yield.. then along came the ttys for a couple of reasons but I think mainly just they can sell more bolts.
There is a little more to it than that as they wanted to downsize everything including the holes in which these bolts resided because there wasn't as much meat in the heads and block and stuff like that around the holes so they didn't want to make the bolts as big and the bolts simply weren't as big with tons of Overkill where they can be used multiple, multiple times like many of the old head bolts on most of the engines I've built over the years were which did just fine.
They decide to use a smaller fastener and then tighten it to the point of starting to stretch so it was giving its most fascinating ability but we all know what happens then it's like a one-time use.
I don't believe these Briggs & Stratton head bolts are designed that way and I also don't believe they're very high quality either. There are some times where I can't quite get them to the new revised torque rating of 250 inch pounds without being afraid one will snap off or strip out the threads so often I don't know quite that high. It used to be 220 or 225 and now it's 250..
I think tightening in three steps which I forgot to mention in my other post, which I always do, and tightening them down evenly is more important than your final torque amount.
I have reused many of these old head bolts multiple times and I just keep them laying in a bowl somewhere they work just as well whether they've been used once or five times in my opinion.
You're not stretching them much if any and you're certainly not stretching them to yield in my opinion when you reinstall the head..
When you get good at the feel for it you can tell if one is out of whack by just using the torque wrench on it or even a 3/8 drive ratchet so maybe if one was messed up or I've been over Titan there could be an issue but other than that I think any old bolts work just as fine as buying brand new ones. Or if we could go buy some ARP head bowls I don't think it would make a bit of difference on these particular engines because it's a lousy design and a lousy gasket.
I have red posts over the past 10 years or so about people who have had more than one head gasket failure and it always astounds me because I have done a lot of these Briggs & Stratton 31xxxx and 33xxxx and I have literally never had a repeat failure!!
Maybe I'm just lucky but I don't think that's the case.
At bare minimum the head needs to be scraped clean with a razor blades scraper or putty knife or whatever and white clean with brake cleaner or carb cleaner or whatever and a rag and the same for the block surface. That's the bare minimum.
Then it is a must that you use the proper head bolt torquing sequence which has been revised and an accurate inch pound torque wrench.
Maybe you're rich is off one way or the other??
I want snapped a rod bolt on a 12-point headed Buick 455 engine because I borrowed a torque wrench when I was a teenager and didn't own one myself and it was calibrated way off! It must have been 25 to 30 lb minimum off because it snapped that off and I had to go to the junkyard to get another one..
So that's all I ever do and I never have failures but if I'm trying to prevent a failure I will go two extra steps..
I will place it on a flat piece of glass or very flat metal with some 60 or 80 grit sandpaper taped down..
Then I will send the heck out of it until the entire surface is even.
This of course isn't as good as actually milling one but you will quickly see the high spots and then as you keep going you're saying will start to hit the other spots so you know you have it much more flat than when you started.
It takes a long time and gets annoying. The last time I counted I had to do at least 500 strokes before I even got close to being smooth and acceptable.
Also, I do it in all different directions as I rotate it a quarter turn throughout the process multiple times.
Then the second thing I will do is spray the permatex copper spray gasket on both sides of the gasket.
Like I said I rarely do either of these and they still last for years after I put them together so I'm very surprised you're having repeated problems.
Are you using the Briggs & Stratton gaskets or the ones you get on eBay and amazon?
In this case the ones that are aftermarket could very well be better than the brakes one because it is junk from beginning and they sell you a same junk when to replace it.
I believe I saw a couple online that seemed to look like they had a fire ring around the combustion chamber which would be an improvement.
When Kohler had this problem back in the early 2000s they recalled all of their original head gaskets and replaced it with a head gasket kit, while
There is no point to prove about head bolts unless you know the design parameters and the materials used of the particular head bolts and we don't.If that is true about headbolts not stretching why do all automobile manufacturers in the workshop manual say to replace all headbolts on aluminum heads and even on some other uses where aluminum parts are used. I remember back in the 1960's that when taking the head of an all aluminum engine Hillman Imp you stood a good chance of breaking headbolts when taking the head of the engine to do a decoke something very few engines nowadays. I know that is about automotive but it proves the point about bolts stretching I believe.
Head bolts in the old days up until the late '80s were never TTY torque to yield.. then along came the ttys for a couple of reasons but I think mainly just they can sell more bolts.
There is a little more to it than that as they wanted to downsize everything including the holes in which these bolts resided because there wasn't as much meat in the heads and block and stuff like that around the holes so they didn't want to make the bolts as big and the bolts simply weren't as big with tons of Overkill where they can be used multiple, multiple times like many of the old head bolts on most of the engines I've built over the years were which did just fine.
They decide to use a smaller fastener and then tighten it to the point of starting to stretch so it was giving its most fascinating ability but we all know what happens then it's like a one-time use.
I don't believe these Briggs & Stratton head bolts are designed that way and I also don't believe they're very high quality either. There are some times where I can't quite get them to the new revised torque rating of 250 inch pounds without being afraid one will snap off or strip out the threads so often I don't know quite that high. It used to be 220 or 225 and now it's 250..
I think tightening in three steps which I forgot to mention in my other post, which I always do, and tightening them down evenly is more important than your final torque amount.
I have reused many of these old head bolts multiple times and I just keep them laying in a bowl somewhere they work just as well whether they've been used once or five times in my opinion.
You're not stretching them much if any and you're certainly not stretching them to yield in my opinion when you reinstall the head..
When you get good at the feel for it you can tell if one is out of whack by just using the torque wrench on it or even a 3/8 drive ratchet so maybe if one was messed up or I've been over Titan there could be an issue but other than that I think any old bolts work just as fine as buying brand new ones. Or if we could go buy some ARP head bowls I don't think it would make a bit of difference on these particular engines because it's a lousy design and a lousy gasket.
#59
H
Honest Abe
H
Honest Abe
if I had to "guess" I'd say that it's because these dang bolts are similar to trying to get nuts of aluminum rims. It seems to take infinitely more torque to break them free than to tighten them down. Just a wild guess though . . . . .Then I ask why it specifically says to replace head bolts in manuals for aluminum block and heads.
I had a 4-wheeler with aluminum block, 650 cc that keep blowing head gaskets after a few hours of running. I made sure there was no cracks or warpage. Come to find out after I finally found a manual on it and after 5 head gasket replacements it stated, "Head bolts must be replaced when head is removed for any reason". It did not give a reason. I purchase all new head bolts and it has been running for about a year now with no problems.
#60
H
Honest Abe
H
Honest Abe
you touched on something I meant to bring up earlier, i.e. "Torque wrench calibration". When was the last time folks had their calibrated? My son builds all kinds of engines for a living, and his are sent out every 6 months and recalibrated. When you're building $75k+ engines little things count, maybe not so much for some and a B&S . . . . . .Well, if you did all that then something wasn't done right or something is atypical and even though you're doing what you're supposed to be doing you're not getting the results and it's letting the procedure fail.
I have red posts over the past 10 years or so about people who have had more than one head gasket failure and it always astounds me because I have done a lot of these Briggs & Stratton 31xxxx and 33xxxx and I have literally never had a repeat failure!!
Maybe I'm just lucky but I don't think that's the case.
At bare minimum the head needs to be scraped clean with a razor blades scraper or putty knife or whatever and white clean with brake cleaner or carb cleaner or whatever and a rag and the same for the block surface. That's the bare minimum.
Then it is a must that you use the proper head bolt torquing sequence which has been revised and an accurate inch pound torque wrench.
Maybe you're rich is off one way or the other??
I want snapped a rod bolt on a 12-point headed Buick 455 engine because I borrowed a torque wrench when I was a teenager and didn't own one myself and it was calibrated way off! It must have been 25 to 30 lb minimum off because it snapped that off and I had to go to the junkyard to get another one..
So that's all I ever do and I never have failures but if I'm trying to prevent a failure I will go two extra steps..
I will place it on a flat piece of glass or very flat metal with some 60 or 80 grit sandpaper taped down..
Then I will send the heck out of it until the entire surface is even.
This of course isn't as good as actually milling one but you will quickly see the high spots and then as you keep going you're saying will start to hit the other spots so you know you have it much more flat than when you started.
It takes a long time and gets annoying. The last time I counted I had to do at least 500 strokes before I even got close to being smooth and acceptable.
Also, I do it in all different directions as I rotate it a quarter turn throughout the process multiple times.
Then the second thing I will do is spray the permatex copper spray gasket on both sides of the gasket.
Like I said I rarely do either of these and they still last for years after I put them together so I'm very surprised you're having repeated problems.
Are you using the Briggs & Stratton gaskets or the ones you get on eBay and amazon?
In this case the ones that are aftermarket could very well be better than the briggs one because it is junk from beginning and they sell you a same junk when to replace it.
I believe I saw a couple online that seemed to look like they had a fire ring around the combustion chamber which would be an improvement.
When Kohler had this problem back in the early 2000s they recalled all of their original head gaskets and replaced it with a head gasket kit, while expensive, it was a much improved head gasket much beefier and with a fire ring around it so the problem would not reoccur.
Briggs does nothing!
#61
K
kjonxx
K
kjonxx
Cheap bolts like kohler maybe ? Running to lean so it gets overly hot.? Just a thought.
#62
T
TobyU
Well, you would stop but in the end, it wouldn't be much different from just leaving alone and wiping it off with a rag after you scraped it in the first place.
These heads are so warped and have such large dips and valleys in them that you're never going to accomplish anything that way.
There is absolutely no problem with laying them on a fairly flat surface, with sandpaper on that surface and working them in all directions as you turn the head around a quarter turn multiple times so this way you're making up for any possible surface of regularities.
I prefer to start with 80 grit but I'm guessing you're going to say that's too course but it works great for me. Sometimes I'll go over it afterwards with something a little bit finer but nothing finer than 120 because this doesn't need to be polished to a smooth surface and you'd be amazed how pretty and smooth they look after doing 500 to 600 strokes with the 80 to 120 grit that I do.
Yes, it takes about 500 strokes doing it this way and I put a good deal of pressure down on the head to get it to where you have actually sanded the whole surface so there's no more high spots holding the rest of the head up off of the sandpaper.
They are that bad. And this is probably why so many people have repeat problems with head gasket failures despite the fact they claim their twerking them in the correct pattern and to the proper specs.
This is not rocket science and it's not very precise either. They are still very forgiving and it does not need any certain type of machine slash engine builders and finish on it to work perfectly.
These engines are actually junky little low performance turds that just luckily are pretty forgiving of most of the abuse, neglect, and design flaws, and low quality parts they're made with.
Sometimes though you have to take matters into your own hand to make a head relatively flat and smooth versus the abomination it was when you removed it.
So sandpaper away I say. It's worked well for me and I've done this more than most human beings alive.
The average person or the majority of people in this group probably haven't done over five in their life and maybe not even over three.
I really don't see that as a large enough sample to prove anything.
T
TobyU
You would literally never get done doing it this way..Almost certainly a warped head, but some of the methods being suggested here to flatten it are a good way to ruin a perfectly good head. Do not use sand paper or concrete both are far to coarse and inaccurate. The best way is to use fine valve grinding paste on a piece of glass, preferably 1/4" or thicker as that's flatter. Do not use a scrap double glazed panel as they're often slightly concave. oil the glass, then smear on some fine valve grinding paste. Place the head on it and move in a figure of eight motion, every dozen or so figures of eight stop, turn the head through 90 degrees and continue. Every so often lift up the head and check the lapped surface, low spots will be obvious. Continue, adding more grinding paste as necessary, until the whole surface is an even mat colour. Wash off, then refit using a new head gasket and torque down gradually, ie bring the bolts up together, do not torque down one fully then the next and so on. If the order is not known tightening diagonally is a good rule of thumb.
One other thing to check is to make sure the bolts (or one possibly) aren't bottoming out too early. Without the head try fitting them, and make sure when fully inserted the gaps between the block and the head of the bolt are all less than the thickness of the head. If they are bottoming out, even when torqued down they won't be squeezing the gasket correctly.
Well, you would stop but in the end, it wouldn't be much different from just leaving alone and wiping it off with a rag after you scraped it in the first place.
These heads are so warped and have such large dips and valleys in them that you're never going to accomplish anything that way.
There is absolutely no problem with laying them on a fairly flat surface, with sandpaper on that surface and working them in all directions as you turn the head around a quarter turn multiple times so this way you're making up for any possible surface of regularities.
I prefer to start with 80 grit but I'm guessing you're going to say that's too course but it works great for me. Sometimes I'll go over it afterwards with something a little bit finer but nothing finer than 120 because this doesn't need to be polished to a smooth surface and you'd be amazed how pretty and smooth they look after doing 500 to 600 strokes with the 80 to 120 grit that I do.
Yes, it takes about 500 strokes doing it this way and I put a good deal of pressure down on the head to get it to where you have actually sanded the whole surface so there's no more high spots holding the rest of the head up off of the sandpaper.
They are that bad. And this is probably why so many people have repeat problems with head gasket failures despite the fact they claim their twerking them in the correct pattern and to the proper specs.
This is not rocket science and it's not very precise either. They are still very forgiving and it does not need any certain type of machine slash engine builders and finish on it to work perfectly.
These engines are actually junky little low performance turds that just luckily are pretty forgiving of most of the abuse, neglect, and design flaws, and low quality parts they're made with.
Sometimes though you have to take matters into your own hand to make a head relatively flat and smooth versus the abomination it was when you removed it.
So sandpaper away I say. It's worked well for me and I've done this more than most human beings alive.
The average person or the majority of people in this group probably haven't done over five in their life and maybe not even over three.
I really don't see that as a large enough sample to prove anything.
#63
T
TobyU
T
TobyU
Ruin a perfectly good head by sanding it with sandpaper on a somewhat flat surface??
My biggest argument will be with calling it a perfectly good head to begin with. Lol
These heads are junk as most lawnmower heads are. At least overhead valve ones with inferior Preston valve guides and they're lousy pressed in seats.
Nothing pinned, nothing staked, nothing!
Lousy little junk engines as I have always called them. Low performance little turds. It's really amazing they perform as well and as long as they do but it's a shame the manufacturers won't do just a couple of little things to solve constant problems and failures.
You couldn't do much to a head to make it much worse on these Briggs engines and their answer for everything is just replace it with a new one! LOL
I've never replaced a Briggs & Stratton OHV head in my life. I had to do a Kawasaki once because the commercial guy kept running it for 2 days or whatever on one cylinder and he burnt so much aluminum out of the head it would have cost more to fix it than it was to buy another one.
But on the briggs, I would never buy a new head because it's not a bit better than the old one that failed.
I fixed them. I put the guides back into place and I staked them and even drilled and pinned a couple. I put seats back in and state them and I'd be willing to bet money they are in better and will stay in better than they were when they were new or a brand new one will.
Briggs & stratton.. perfectly good head.. that's funny right there.
My biggest argument will be with calling it a perfectly good head to begin with. Lol
These heads are junk as most lawnmower heads are. At least overhead valve ones with inferior Preston valve guides and they're lousy pressed in seats.
Nothing pinned, nothing staked, nothing!
Lousy little junk engines as I have always called them. Low performance little turds. It's really amazing they perform as well and as long as they do but it's a shame the manufacturers won't do just a couple of little things to solve constant problems and failures.
You couldn't do much to a head to make it much worse on these Briggs engines and their answer for everything is just replace it with a new one! LOL
I've never replaced a Briggs & Stratton OHV head in my life. I had to do a Kawasaki once because the commercial guy kept running it for 2 days or whatever on one cylinder and he burnt so much aluminum out of the head it would have cost more to fix it than it was to buy another one.
But on the briggs, I would never buy a new head because it's not a bit better than the old one that failed.
I fixed them. I put the guides back into place and I staked them and even drilled and pinned a couple. I put seats back in and state them and I'd be willing to bet money they are in better and will stay in better than they were when they were new or a brand new one will.
Briggs & stratton.. perfectly good head.. that's funny right there.
#64
S
SlopeMan2
S
SlopeMan2
SureI have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#65
S
SlopeMan2
S
SlopeMan2
Sure sounds like something is not true and straight. I have run over 20 B&S engines during the past 50 years, and have not blown one head gasket. I did on my Ford and Chevy engines, but never on a Kolar or Briggs. Something is unusual alright. Something didn't come out right on that engine. I had a drag engine specialist tell me that he had seen the line bore on a V/8 1/4" out of line. He found that those engines don't make it very long. Good luck.
#66
U
unkwnmike
U
unkwnmike
I believe you need the right torque sequence. also you might try making your own gasket with permatexI have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#67
T
TobyU
It's really not "if" but "when".
I think it's all about heat cycles and not hours at all though.
Most people fire up their rider once every 7-10 days and run it for 45 mins to 1hr and 15 mins.
I feel if a person keeps several of these 10+years and 185-225 hrs, they will see blown head gaskets.
Someone who cuts 4 times as much after each start could wear the machine or and replace it with newer before the gasket ever gives way.
I don't think there is anything you can do to make them more likely to last unless your mowing fits the longer pattern.
T
TobyU
The single v twin ohv Briggs are notorious for this.Sure sounds like something is not true and straight. I have run over 20 B&S engines during the past 50 years, and have not blown one head gasket. I did on my Ford and Chevy engines, but never on a Kolar or Briggs. Something is unusual alright. Something didn't come out right on that engine. I had a drag engine specialist tell me that he had seen the line bore on a V/8 1/4" out of line. He found that those engines don't make it very long. Good luck.
It's really not "if" but "when".
I think it's all about heat cycles and not hours at all though.
Most people fire up their rider once every 7-10 days and run it for 45 mins to 1hr and 15 mins.
I feel if a person keeps several of these 10+years and 185-225 hrs, they will see blown head gaskets.
Someone who cuts 4 times as much after each start could wear the machine or and replace it with newer before the gasket ever gives way.
I don't think there is anything you can do to make them more likely to last unless your mowing fits the longer pattern.
#68
J
Joe In Des Moines
J
Joe In Des Moines
How are you lapping your surfaces?
I got hold of a good sized chunk of marble counter top. I spread out some valve lapping compound on the marble (med grit), along with a bit on the head or block (whatever I'm wanting to make flat) then start in using random orbital motion. Using no consistent pattern, go in an oval clockwise, then counter clockwise, then throw in a circular motion, a figure 8, whatever motion comes to mind EXCEPT FOR straight line back and forth. That's a big NO NO !
Every 5 - 7 minutes or so, stop and clean off your surface with Brakleen or whatever. If you have a low spot, it WILL show up. If so, go back at it.
It's time consuming, and it'll give you a work out, but it WILL be flat when you're done !
Once all is flat, give everything a thorough cleaning. Remember to get all of the lapping compound cleaned out as it IS a cutting agent. Follow all the other steps and that engine should run better than ever !!
I got hold of a good sized chunk of marble counter top. I spread out some valve lapping compound on the marble (med grit), along with a bit on the head or block (whatever I'm wanting to make flat) then start in using random orbital motion. Using no consistent pattern, go in an oval clockwise, then counter clockwise, then throw in a circular motion, a figure 8, whatever motion comes to mind EXCEPT FOR straight line back and forth. That's a big NO NO !
Every 5 - 7 minutes or so, stop and clean off your surface with Brakleen or whatever. If you have a low spot, it WILL show up. If so, go back at it.
It's time consuming, and it'll give you a work out, but it WILL be flat when you're done !
Once all is flat, give everything a thorough cleaning. Remember to get all of the lapping compound cleaned out as it IS a cutting agent. Follow all the other steps and that engine should run better than ever !!
#69
L
lofty66
L
lofty66
You would literally never get done doing it this way..
Well, you would stop but in the end, it wouldn't be much different from just leaving alone and wiping it off with a rag after you scraped it in the first place.
These heads are so warped and have such large dips and valleys in them that you're never going to accomplish anything that way.
There is absolutely no problem with laying them on a fairly flat surface, with sandpaper on that surface and working them in all directions as you turn the head around a quarter turn multiple times so this way you're making up for any possible surface of regularities.
I prefer to start with 80 grit but I'm guessing you're going to say that's too course but it works great for me. Sometimes I'll go over it afterwards with something a little bit finer but nothing finer than 120 because this doesn't need to be polished to a smooth surface and you'd be amazed how pretty and smooth they look after doing 500 to 600 strokes with the 80 to 120 grit that I do.
Yes, it takes about 500 strokes doing it this way and I put a good deal of pressure down on the head to get it to where you have actually sanded the whole surface so there's no more high spots holding the rest of the head up off of the sandpaper.
They are that bad. And this is probably why so many people have repeat problems with head gasket failures despite the fact they claim their twerking them in the correct pattern and to the proper specs.
This is not rocket science and it's not very precise either. They are still very forgiving and it does not need any certain type of machine slash engine builders and finish on it to work perfectly.
These engines are actually junky little low performance turds that just luckily are pretty forgiving of most of the abuse, neglect, and design flaws, and low quality parts they're made with.
Sometimes though you have to take matters into your own hand to make a head relatively flat and smooth versus the abomination it was when you removed it.
So sandpaper away I say. It's worked well for me and I've done this more than most human beings alive.
The average person or the majority of people in this group probably haven't done over five in their life and maybe not even over three.
I really don't see that as a large enough sample to prove anything.
#70
L
lofty66
L
lofty66
Wow generations of engineers have been wrong - what I suggested in the recommended procedure that's been taught since engines were invented. Heads only ever warp by a few thou and half an hour using glass and grinding paste will leave the surface perfectly flat. If half an hour is too long for you, pay a professional to do it properly rather than b' it up with a five minute bodge.
#71
J
jagg2236
J
jagg2236
I've learned "no more Husq's anything", through their chainsaw engine's "eating pistons & cylinders". Yes junk!I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#72
D
Dobber
D
Dobber
Check the valve clearance, double check torque on head bolts.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#73
B
bertsmobile1
Not many car engines blow head gaskets on alloy block alloy head engines between the cylinder & pushrod tube .
In the case of these engines it is not head warp it is EROSION of the bridge which can be anything from 0.0005" to 0.030" ( worst one I have had in the shop ) .
Sorting this out with lapping paste will take a month of Sundays particularly as in many cases it will be in both the head & the barrel
In many case owners just put up with the leak till the mower will no longer start then they bring it to me & tell me "it has been making funny noises when I turn the blades on for the past 3 or 4 years but it sorts itself out after a few minutes"
B
bertsmobile1
Once again this is CAR technology being blindly applied to mowers where it does not necessarily hold.Wow generations of engineers have been wrong - what I suggested in the recommended procedure that's been taught since engines were invented. Heads only ever warp by a few thou and half an hour using glass and grinding paste will leave the surface perfectly flat. If half an hour is too long for you, pay a professional to do it properly rather than b' it up with a five minute bodge.
Not many car engines blow head gaskets on alloy block alloy head engines between the cylinder & pushrod tube .
In the case of these engines it is not head warp it is EROSION of the bridge which can be anything from 0.0005" to 0.030" ( worst one I have had in the shop ) .
Sorting this out with lapping paste will take a month of Sundays particularly as in many cases it will be in both the head & the barrel
In many case owners just put up with the leak till the mower will no longer start then they bring it to me & tell me "it has been making funny noises when I turn the blades on for the past 3 or 4 years but it sorts itself out after a few minutes"
#75
B
Bertrrr
B
Bertrrr
Use a straight edge across the whole surface of both the head and block , most likely the head - see if you can get a feeler gauge under your straight edge at any area or look for daylight between the 2.
#76
T
TobyU
My point and response to you was I don't think you'd ever get done just using valve compound and plus that stuff's very expensive. You claim that there were lots of wrong responses in this thread and that sandpaper was one of them and several good ways to ruin a perfectly good head which I completely disagree with.
There are several ways to end up with the same result desired which is a head that is flatter and what you begin with..
T
TobyU
Not sure who you're responding to but this is a lengthy process. I have stated in a couple of posts that I use well over 500 to 600 strokes to get one to where it looks pretty uniform and all the high spots are knocked down.Wow generations of engineers have been wrong - what I suggested in the recommended procedure that's been taught since engines were invented. Heads only ever warp by a few thou and half an hour using glass and grinding paste will leave the surface perfectly flat. If half an hour is too long for you, pay a professional to do it properly rather than b' it up with a five minute bodge.
My point and response to you was I don't think you'd ever get done just using valve compound and plus that stuff's very expensive. You claim that there were lots of wrong responses in this thread and that sandpaper was one of them and several good ways to ruin a perfectly good head which I completely disagree with.
There are several ways to end up with the same result desired which is a head that is flatter and what you begin with..
#77
T
TobyU
I also do circles and diagonals and everything else because it gets pretty boring when you're doing it. It helps to have a good song going at a proper pace to keep up the tempo!
Make sure you alternate arms too because that way you get an equal workout. Lol
T
TobyU
It certainly is very time consuming and the last time I counted I was between $500 and 600 strokes but I have no problem with going in straight lines as long as you're rotating the head frequently which I typically do quarter turn rotations after every 30 or 40 strokes..How are you lapping your surfaces?
I got hold of a good sized chunk of marble counter top. I spread out some valve lapping compound on the marble (med grit), along with a bit on the head or block (whatever I'm wanting to make flat) then start in using random orbital motion. Using no consistent pattern, go in an oval clockwise, then counter clockwise, then throw in a circular motion, a figure 8, whatever motion comes to mind EXCEPT FOR straight line back and forth. That's a big NO NO !
Every 5 - 7 minutes or so, stop and clean off your surface with Brakleen or whatever. If you have a low spot, it WILL show up. If so, go back at it.
It's time consuming, and it'll give you a work out, but it WILL be flat when you're done !
Once all is flat, give everything a thorough cleaning. Remember to get all of the lapping compound cleaned out as it IS a cutting agent. Follow all the other steps and that engine should run better than ever !!
I also do circles and diagonals and everything else because it gets pretty boring when you're doing it. It helps to have a good song going at a proper pace to keep up the tempo!
Make sure you alternate arms too because that way you get an equal workout. Lol
#78
T
TobyU
Some manufacturers even put a bolt in the middle there that would even go through and protrude into the intake runner which would be just fine.
All you have to do is have the right length bolt to where it comes out pretty much at the end and the turbulence etc is not going to be worth mentioning especially not compared to repeated blowing of gaskets because of too much distance between the two right bolt holes.
T
TobyU
It's an obvious design flaw that's been known for decades but Briggs refused to fix it.
Some manufacturers even put a bolt in the middle there that would even go through and protrude into the intake runner which would be just fine.
All you have to do is have the right length bolt to where it comes out pretty much at the end and the turbulence etc is not going to be worth mentioning especially not compared to repeated blowing of gaskets because of too much distance between the two right bolt holes.
#79
B
bertsmobile1
B
bertsmobile1
Sand paper might mean some thing different in the USA
Down here is means just that, screened sand glued to paper used on plastics & wood
Wet & dry is what you use for lapping and by prefference on a flat but sloped surface with water feed to the top to lubricate the sheet & wash away the debris .
Automotive engines usually fail between cylinders so the engine will not start so it is not run in the damaged condition for very long
Or that fail between the cylinder & water jacket, same thing, boiled engine shut down before major damage is done
Mower engines are often run for years with a failed gasket till eventually they can not be made to start even with starter fluid .
Down here is means just that, screened sand glued to paper used on plastics & wood
Wet & dry is what you use for lapping and by prefference on a flat but sloped surface with water feed to the top to lubricate the sheet & wash away the debris .
Automotive engines usually fail between cylinders so the engine will not start so it is not run in the damaged condition for very long
Or that fail between the cylinder & water jacket, same thing, boiled engine shut down before major damage is done
Mower engines are often run for years with a failed gasket till eventually they can not be made to start even with starter fluid .
#80
G
G5200
G
G5200
Funny you should mention that about putting the bolt in the middle. I finally got tired of replacing head gaskets and a flywheel that cracked off a piece at the keyway and replaced it with a JD labelled engine, just so I could sell it. A few weeks after it left for it's new home I went to visit a friend, who had just purchased the same model tractor. Within a few months he had similar issues. Being an even more stubborn person than myself, he drilled & tapped a hole in the block and a clearance hole in the head for either a .190 or .250 bolt (Inco718, of course). That actually fixed the problem for several years.It's an obvious design flaw that's been known for decades but Briggs refused to fix it.
Some manufacturers even put a bolt in the middle there that would even go through and protrude into the intake runner which would be just fine.
All you have to do is have the right length bolt to where it comes out pretty much at the end and the turbulence etc is not going to be worth mentioning especially not compared to repeated blowing of gaskets because of too much distance between the two right bolt holes.
#81
T
TobyU
Has myself and others have stated though this should not be a recurring problem. I have never had one fail a second time and I don't even always mill the heads down on a flat surface..
I have done many of these by just scraping off the head and getting it nice and clean and not even putting a straight edge on it to see if it's warped at all!
I simply clean the head and the block up thoroughly and put the new Briggs & Stratton gasket on there as I have never used an aftermarket gasket even though I think there's a potential they could be better than the factory one and I torque it now with the new tightening pattern and the 250 inch pounds procedure but I used to do these with the old torque sequence and the 220 or 225 or whatever it was and I still never had any failures back then either.
So while it is an epidemic problem, once I put a new gasket on there it's not been an epidemic problem in the future at all.
However, if I were having repeated failures I would certainly take extra steps and if milling the head flat and permatex spray gasket didn't solve the problem I would be drilling a hole and tapping some bolt threads!!
T
TobyU
I I was going to mention just doing that in my other post but they really didn't design it for that and there's an awfully large pushrod galley that doesn't need to be so big so they would have had more metal between the cylinder and the opening but you could certainly put something there with the metal that you do have and it would help the issue.Funny you should mention that about putting the bolt in the middle. I finally got tired of replacing head gaskets and a flywheel that cracked off a piece at the keyway and replaced it with a JD labelled engine, just so I could sell it. A few weeks after it left for it's new home I went to visit a friend, who had just purchased the same model tractor. Within a few months he had similar issues. Being an even more stubborn person than myself, he drilled & tapped a hole in the block and a clearance hole in the head for either a .190 or .250 bolt (Inco718, of course). That actually fixed the problem for several years.
Has myself and others have stated though this should not be a recurring problem. I have never had one fail a second time and I don't even always mill the heads down on a flat surface..
I have done many of these by just scraping off the head and getting it nice and clean and not even putting a straight edge on it to see if it's warped at all!
I simply clean the head and the block up thoroughly and put the new Briggs & Stratton gasket on there as I have never used an aftermarket gasket even though I think there's a potential they could be better than the factory one and I torque it now with the new tightening pattern and the 250 inch pounds procedure but I used to do these with the old torque sequence and the 220 or 225 or whatever it was and I still never had any failures back then either.
So while it is an epidemic problem, once I put a new gasket on there it's not been an epidemic problem in the future at all.
However, if I were having repeated failures I would certainly take extra steps and if milling the head flat and permatex spray gasket didn't solve the problem I would be drilling a hole and tapping some bolt threads!!
#82
B
bertsmobile1
B
bertsmobile1
I used to fit the Stens gaskets which are cut from the same sheet material as exhaust gaskets and work a lot better
However they only do 1 size down here so I found a supply of after market ones in a kit that are the same material as the B & S ones and come with rocker cover gasket.
Down side was MOQ was 50 but as I do quite a few of them then that was not a big problem .
If the same mower comes back twice then they get one of Lanni's copper gaskets, they never ever come back.
I also use the copper gaskets if the block is under cut as the copper will conform to the shape if the head is flat
And some times even fill a big undercut with POR15 or Devcon and in that case it also gets a copper gasket .
Lanni is goon because he makes up packages for me that are the full weight limit
From memory that is 7 intek only gaskets but as I buy a lot of gaskets from him I often make up weight with them when ordering 1 of unique gaskets .
The intek is taken from the Vanguard and if yo put them side by side you see the Vanguard has a lot more thickness and a better bolt positioning .
as with a lot of these things , they are cast on a machine that has dozens of moulds on a carousel so if one mould is not as good as the the others then 1 in 10,20, 30 etc will be weaker.
Then there is start up & shut down faults plus Silicon burn off so at the end of the day the actual mo;ten alloy in the furnace changes slightly.
All of these things can introduce random faults in a small percentage of the castings that are very hard to pick up in QC so you get a small percentages of Inteks that just keep on blowing the gaskets , just the same as a small percentage of Courage engines developed that cylinder crack .
It all comes down to the reluctance of the purchaser to pay a reasonable price as we have all been indoctrinated ( brain washed if you like ) that everything will get cheaper because of advances in manufacturing technology so we will be able to afford what ever we want .
There is a sound reason why there are no more mowers with Honda or Generac engine in them and it was not because the engines were trash & constantly gave problems.
However they only do 1 size down here so I found a supply of after market ones in a kit that are the same material as the B & S ones and come with rocker cover gasket.
Down side was MOQ was 50 but as I do quite a few of them then that was not a big problem .
If the same mower comes back twice then they get one of Lanni's copper gaskets, they never ever come back.
I also use the copper gaskets if the block is under cut as the copper will conform to the shape if the head is flat
And some times even fill a big undercut with POR15 or Devcon and in that case it also gets a copper gasket .
Lanni is goon because he makes up packages for me that are the full weight limit
From memory that is 7 intek only gaskets but as I buy a lot of gaskets from him I often make up weight with them when ordering 1 of unique gaskets .
The intek is taken from the Vanguard and if yo put them side by side you see the Vanguard has a lot more thickness and a better bolt positioning .
as with a lot of these things , they are cast on a machine that has dozens of moulds on a carousel so if one mould is not as good as the the others then 1 in 10,20, 30 etc will be weaker.
Then there is start up & shut down faults plus Silicon burn off so at the end of the day the actual mo;ten alloy in the furnace changes slightly.
All of these things can introduce random faults in a small percentage of the castings that are very hard to pick up in QC so you get a small percentages of Inteks that just keep on blowing the gaskets , just the same as a small percentage of Courage engines developed that cylinder crack .
It all comes down to the reluctance of the purchaser to pay a reasonable price as we have all been indoctrinated ( brain washed if you like ) that everything will get cheaper because of advances in manufacturing technology so we will be able to afford what ever we want .
There is a sound reason why there are no more mowers with Honda or Generac engine in them and it was not because the engines were trash & constantly gave problems.
#83
C
closecut
A washer under the head bots is a cheap fix,but the best way is new head bolts,or grade 8 bolts from the local hardware store.May have to go to an automotive store to find grade 8 bolts. They cost more,but will not stretch.
Also,use a Felpro gasket.The OEM has a very thin section between the plug and block.Felpro is much wider.
Run for a few minutes,and then let it cool and tighten the head bolts again to spec.
This is after doing the recommended checks above.Let us know how it comes out,don't leave us hanging.
Good luck!
C
closecut
Do you use starting fluid?This will blow a head gasket if used to much.It can also STRETCH the head bolts,and the bolts will bottom out without actually crimping down on the head properly.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
A washer under the head bots is a cheap fix,but the best way is new head bolts,or grade 8 bolts from the local hardware store.May have to go to an automotive store to find grade 8 bolts. They cost more,but will not stretch.
Also,use a Felpro gasket.The OEM has a very thin section between the plug and block.Felpro is much wider.
Run for a few minutes,and then let it cool and tighten the head bolts again to spec.
This is after doing the recommended checks above.Let us know how it comes out,don't leave us hanging.
Good luck!
#84
C
closecut
C
closecut
No firing order found?Here is an old school method to get the tightening sequence right:
Start in the center and tighten in a expanding circle from the center outward.
Imagine flattening a sheet of paper from the center.Same thing.You want the wrinkles to go toward the ends.The metal is flexible,but not visible,but it does act like stiff paper.Even cast iron heads on big engines flex as they are tightened.
Start in the center and tighten in a expanding circle from the center outward.
Imagine flattening a sheet of paper from the center.Same thing.You want the wrinkles to go toward the ends.The metal is flexible,but not visible,but it does act like stiff paper.Even cast iron heads on big engines flex as they are tightened.
#85
H
hlw49
H
hlw49
Might what to check and see if the head is flat. I take a large piece of artifical granite and emery cloth and lap the head. Use 400 grit emery cloth. You can use a piece of glass it works as well.
#86
G
grpascott
G
grpascott
Hi Oar,
Here's what I did, it's lasted 4 years so far.
Engine started to smoke once in a while, I knew Inteks had a bolt pattern (spacing) problem. The head bolts are also a lousy alloy. I went and got grade 8 bolts the same length. They weren't threaded far enough so I got a die and threaded them deep enough to torque down. I didn't even take the head off, just took the old bolts out and replaced and retorqued one by one to 22 ft lbs (264 in lbs). No more smoking or problems since then. I also use a little zinc additive in the oil to protect the flat tappets. This may sound a little involved but I'm a born tinkerer and I love to make lousy engineering work. Hope you give it a try, never give up...never surrender!!
Here's what I did, it's lasted 4 years so far.
Engine started to smoke once in a while, I knew Inteks had a bolt pattern (spacing) problem. The head bolts are also a lousy alloy. I went and got grade 8 bolts the same length. They weren't threaded far enough so I got a die and threaded them deep enough to torque down. I didn't even take the head off, just took the old bolts out and replaced and retorqued one by one to 22 ft lbs (264 in lbs). No more smoking or problems since then. I also use a little zinc additive in the oil to protect the flat tappets. This may sound a little involved but I'm a born tinkerer and I love to make lousy engineering work. Hope you give it a try, never give up...never surrender!!
#87
B
barny57
B
barny57
Do you use starting fluid?This will blow a head gasket if used to much.It can also STRETCH the head bolts,and the bolts will bottom out without actually crimping down on the head properly.
A washer under the head bots is a cheap fix,but the best way is new head bolts,or grade 8 bolts from the local hardware store.May have to go to an automotive store to find grade 8 bolts. They cost more,but will not stretch.
Also,use a Felpro gasket.The OEM has a very thin section between the plug and block.Felpro is much wider.
Run for a few minutes,and then let it cool and tighten the head bolts again to spec.
This is after doing the recommended checks above.Let us know how it comes out,don't leave us hanging.
Good luck!
Like the guys said, bolts, flat head, gasket, solve your problemI have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#88
T
TobyU
The most common one for these is going to be the Briggs which has not been approved at all and is the same old one they've been using for 20 years that certainly will blow out because of the bad design of the head and the too much spacing between the right to head bolts.
I have seen other like aftermarket ones online often where you get two or at least the gasket and some other additional gaskets for a cheaper price than the Briggs and some of these are actually better built and you might even find one with a fire ring around the combustion cylinder but don't quote me on that BUT unless I'm really out of the loop, I've never seen a felpro for one of these 31XXXX or 33xXXXX Briggs.
T
TobyU
How are you possibly going to find a felpro gasket for a lawn mower engine?Do you use starting fluid?This will blow a head gasket if used to much.It can also STRETCH the head bolts,and the bolts will bottom out without actually crimping down on the head properly.
A washer under the head bots is a cheap fix,but the best way is new head bolts,or grade 8 bolts from the local hardware store.May have to go to an automotive store to find grade 8 bolts. They cost more,but will not stretch.
Also,use a Felpro gasket.The OEM has a very thin section between the plug and block.Felpro is much wider.
Run for a few minutes,and then let it cool and tighten the head bolts again to spec.
This is after doing the recommended checks above.Let us know how it comes out,don't leave us hanging.
Good luck!
The most common one for these is going to be the Briggs which has not been approved at all and is the same old one they've been using for 20 years that certainly will blow out because of the bad design of the head and the too much spacing between the right to head bolts.
I have seen other like aftermarket ones online often where you get two or at least the gasket and some other additional gaskets for a cheaper price than the Briggs and some of these are actually better built and you might even find one with a fire ring around the combustion cylinder but don't quote me on that BUT unless I'm really out of the loop, I've never seen a felpro for one of these 31XXXX or 33xXXXX Briggs.
#89
T
TobyU
Those bolts are fairly wimpy so it certainly wouldn't hurt to replace it with new ones and especially much better ones like grade 8.
However, a lot of people just use their 3/8 Drive fraction and tighten these things up by hand in any haphazard order.
I don't think the order matters nearly as much as getting them properly torqued or at least torqued enough and not too much so as to stretch the bolt or snap It off - which I'm not really convinced is the same as that thing as properly torqued. Lol
You just must have an inch pound torque wrench for this and it must be accurate because many are not.
Also, as you mentioned, these heads are normally not flat. Some aren't even close.
If I'm doing one I really care about, I will lay it on a piece of 60 or 80 grit sandpaper on a piece of plate glass or something quite extremely flat and do a little backyard Mill job of the head .
It's not perfect but it doesn't have to be and it certainly makes it a lot better.
In just a few strokes you start to see where the high spots are being rubbed off but it takes a long time to get down to where you've touched the head everywhere because the high spots are no longer that high.
When you do this you want to change the direction of the head in your hand like rotate it a quarter and a half turn many times as you're pushing it back and forth applying pressure on your sandpaper.
I normally tape the sandpaper down with duct tape.
The last time I did one I counted and it was almost 600 strokes until I got it to where it was evenly sanded..
This can take 20 to 30 minutes and then you want to remove all of the nasty sanding grit and metal shavings.
But then you have a much flatter head and then of course you want to clean up the block service with a scraper and maybe some fine sandpaper etc but don't sand it any one spot too long because you're not doing the flatness any favors by standing around with sandpaper on your fingertip!
I have never had one of these fail once replacing them.
I hear people that have had repeated failures and I only can assume they're just yanking it off and wiping off the head and the surface with a shop cloth and barely, if even, scraping off all the old gasket and then throwing it back together and just tightening It up by hand without using a torque wrench.
This is what I assume contributes to most of these failures.
T
TobyU
Yep, and also using a torque wrench and maybe even the Briggs recommended tightening sequence for the bolts.Like the guys said, bolts, flat head, gasket, solve your problem
Those bolts are fairly wimpy so it certainly wouldn't hurt to replace it with new ones and especially much better ones like grade 8.
However, a lot of people just use their 3/8 Drive fraction and tighten these things up by hand in any haphazard order.
I don't think the order matters nearly as much as getting them properly torqued or at least torqued enough and not too much so as to stretch the bolt or snap It off - which I'm not really convinced is the same as that thing as properly torqued. Lol
You just must have an inch pound torque wrench for this and it must be accurate because many are not.
Also, as you mentioned, these heads are normally not flat. Some aren't even close.
If I'm doing one I really care about, I will lay it on a piece of 60 or 80 grit sandpaper on a piece of plate glass or something quite extremely flat and do a little backyard Mill job of the head .
It's not perfect but it doesn't have to be and it certainly makes it a lot better.
In just a few strokes you start to see where the high spots are being rubbed off but it takes a long time to get down to where you've touched the head everywhere because the high spots are no longer that high.
When you do this you want to change the direction of the head in your hand like rotate it a quarter and a half turn many times as you're pushing it back and forth applying pressure on your sandpaper.
I normally tape the sandpaper down with duct tape.
The last time I did one I counted and it was almost 600 strokes until I got it to where it was evenly sanded..
This can take 20 to 30 minutes and then you want to remove all of the nasty sanding grit and metal shavings.
But then you have a much flatter head and then of course you want to clean up the block service with a scraper and maybe some fine sandpaper etc but don't sand it any one spot too long because you're not doing the flatness any favors by standing around with sandpaper on your fingertip!
I have never had one of these fail once replacing them.
I hear people that have had repeated failures and I only can assume they're just yanking it off and wiping off the head and the surface with a shop cloth and barely, if even, scraping off all the old gasket and then throwing it back together and just tightening It up by hand without using a torque wrench.
This is what I assume contributes to most of these failures.
#90
M
melvin1942
M
melvin1942
Have you checked the flatness of the head and block?I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#91
S
SlopeMan2
S
SlopeMan2
Sorry you are having so much trouble with headgaskets. I guess I am lucky. I have 4 mowers now with over 2,500 hours on them collectively, B&C and Kohlar. And I have put at least 2,500 hours on others in the past (know on wood). I do not recall even replacing one headgasket. There could have been a casting problem. Either the head or block is untrue. I remember a race car machinist telling me once, that he had seen a crankshaft linebore 1/4" out of line with the cylinders. He said a motor with a block like that will not last long. I am 88, and have had extremely good luck B&S & Kohlar. Best of luck finding out what is wrong.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#92
S
slomo
S
slomo
I would take a ratchet/socket yearly, check for head bolt snugness. Simple see if it turns from being loose. Not trying to apply much torque. Better yet the ol' torque wrench. Only takes two shakes of a lambs tail.
Clean the cooling fins while you are at it. I know what cooling fins?
Clean the cooling fins while you are at it. I know what cooling fins?
#93
J
Joed756
J
Joed756
An old diesel mechanic trick...use two head gaskets.I have a Husquvarna tractor. 18.5hp. Can anyone tell me why I have gone thru 4 head gaskets? This one being the 4th. Blows out right across from the plug. There is no way I screwed up 3 headgaskets. Getting a little tired of this crap. Are these engines junk? I can change a hot cylinder in a 2500hp EMD but can't keep this running. Should sell everything and buy a diesel....
#94
F
Forest#2
F
Forest#2
joed756 said:
An old diesel mechanic trick...use two head gaskets.
Good info here
I've done the two head gasket with good results. (do the proper torque procedure)
Also it will slightly reduce the compression which can be a good thing on some engines.
An old diesel mechanic trick...use two head gaskets.
Good info here
I've done the two head gasket with good results. (do the proper torque procedure)
Also it will slightly reduce the compression which can be a good thing on some engines.