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Craftsman head gasket issue?

#1

R

Rickcin

I have a Craftsman tractor with a 18.5 hp Briggs & Stratton ohv Intek engine. After about 3 years of light use the head gasket went and I paid Sears to replace it. Now it is about 3years since it has been replaced and it appears to have the same symptoms, blue smoke when you engage the blades and now using oil again.
I would imagine this is a typical problem with this engine since the head gasket is extremely narrow at one specific area.

Any one else experiencing this problem? I guess there is no real solution. Thanks


#2

S

SeniorCitizen

I haven't experienced it but I've read of head gasket failures a few years ago and I believe the general consensus was the head bolt spacing was too great in the area where it fails. Poor design and no correction I know of unless maybe JB weld the gasket.


#3

R

Rickcin

SeniorCitizen said:
I haven't experienced it but I've read of head gasket failures a few years ago and I believe the general consensus was the head bolt spacing was too great in the area where it fails. Poor design and no correction I know of unless maybe JB weld the gasket.
Click to expand...

It is all over youtube regarding the narrow area of the gasket that fails. I called Sears and they have indicated it was replaced in Oct. of 2010, so it lasted less than 4 years.
They charged me $210 back then and I am sure it would cost more now.

I am wondering if I should try the repair myself?


#4

S

SeniorCitizen

Sure, DIY. There is help here on the form if you hit a difficult spot. Download the manual if possible. Rather than buying a torque wrench I suspect you can rent one.

If you aren't familiar with the mechanic world, take pictures, label parts, nuts and bolts. Example: there are engines where all head blots may not be of equal length because of various reasons. Note where it / they came from.


#5

R

Rivets

If you are a little mechanically savvy, you should be able to replace the gasket yourself. Less that an afternoon job. Post your engine numbers and I'll find you a service manual and get a list of parts you will need. I'm pretty busy, but I'll get back to you ASAP.


#6

Fish

Fish

Yeah, a simple repair!!!


#7

R

Rickcin

Rivets said:
If you are a little mechanically savvy, you should be able to replace the gasket yourself. Less that an afternoon job. Post your engine numbers and I'll find you a service manual and get a list of parts you will need. I'm pretty busy, but I'll get back to you ASAP.
Click to expand...

Really great site with lots of helpful members. I do have a torque wrench and I am somewhat mechanically inclined, so I guess I should attempt it. Not willing to spend another $250 or so to have it done if I could do it myself.

I will find the engine number and let you know. Thanks so much - Rick


#8

tigercat

tigercat

I have a 5 year old yard tractor with the B&S 21 HP engine and it let go last fall mulching leaves. I repaired it myself. I did my brothers Craftsman 4 months ago, it was about 17 HP but 10 years old.
Hardest part in doing the head gasket is the clean up process before you install the new gaskets.
I like Briggs engines, but the ohv engines may change my opinion of them in the future.


#9

R

Rickcin

tigercat said:
I have a 5 year old yard tractor with the B&S 21 HP engine and it let go last fall mulching leaves. I repaired it myself. I did my brothers Craftsman 4 months ago, it was about 17 HP but 10 years old.
Hardest part in doing the head gasket is the clean up process before you install the new gaskets.
I like Briggs engines, but the ohv engines may change my opinion of them in the future.
Click to expand...

What is the best way to clean the head and the top of the block and piston?


#10

tigercat

tigercat

I use a medium soft wire cup that attaches to a 3/8" drill. When the head is off wire brush all the gasket material off the mating parts. Set the steel valve guide rod aside along with the aluminum one. The steel goes back on the exhaust side (top) of the engine when you put it back in. You need to reset the valves arpund .004 intake .006 exhaust @ 1/4" down from top dead center on the engine. (simply roll the engine using the pulley underneth to top dead center (piston up / valves closed) then go 1/4" more (stick a screw driver in the spark plug hole to make sure the piston is where you want it).
You need to get a tube of gasket sealing goop for the valve vover, as this might leak on the muffler after you get it running again.
It's easy to do the job, a feeler gauge & basic tools needed. You may want to get a torque wrench for the head, to final set them to required specs.

I can look up the specs to make sure everything is correct later.

This guy is a superb small engine mechanic. Check how easy it is to do a head gasket.
This video might be it or just search his channel.

http://youtu.be/UaG75e1DhLo


#11

R

Rickcin

Rivets said:
If you are a little mechanically savvy, you should be able to replace the gasket yourself. Less that an afternoon job. Post your engine numbers and I'll find you a service manual and get a list of parts you will need. I'm pretty busy, but I'll get back to you ASAP.
Click to expand...

18.5 B&S OHV Intek plus Model# 31P777 0348E1 04100 42D

Thanks - Rick


#12

tigercat

tigercat

I have better luck just using the engine number stamped on the valve cover. With that model number and serial number, just search B&S engine for proper parts needed.

Head gasket
spark plug
valve cover gasket
exhaust gasket
intake gasket


#13

I

ILENGINE

part number 794152 valve overhaul gasket set, includes the head gasket, exhaust gasket, intake gasket, valve stem seal, and the valve cover gasket.


#14

R

Rivets

This manual should help you out.

https://docs.google.com/open?id=0B6NaqjIxWV1ySHZ6elRSdWo3ZVk


#15

R

Rickcin

tigercat said:
I have better luck just using the engine number stamped on the valve cover. With that model number and serial number, just search B&S engine for proper parts needed.

Head gasket
spark plug
valve cover gasket
exhaust gasket
intake gasket
Click to expand...

I checked out the YouTube video you sent and it is a great step by step. The valve adjustment is the only only thing that concerns me. Turn the crank 1/4 turn and then use the feeler gauge? Does not seem like an exact science.
I need to find the head torque setting and the valve settings. The YouTube said .003 and .004 for the valves?

Also, I guess you do not use gasket seal on the head gasket? Thanks - Rick


#16

tigercat

tigercat

Rickcin said:
I checked out the YouTube video you sent and it is a great step by step. The valve adjustment is the only only thing that concerns me. Turn the crank 1/4 turn and then use the feeler gauge? Does not seem like an exact science.
I need to find the head torque setting and the valve settings. The YouTube said .003 and .004 for the valves?

Also, I guess you do not use gasket seal on the head gasket? Thanks - Rick
Click to expand...

The B&S manual says once you reach top dead ceter, rotate engine clockwise, as you watch the piston drop 1/4". I don't rotate flywheel 1/4", maybe it works the same, I never checked.

Correct, no thread sealant anywhere, but on the valve cover. Sometimes they leak oil and it will smoke up on the muffler.

I need the "model series" of the engine for exact valve clearance specs. Normally they are around .003-.006 where the exhaust side will be larger by .001

I don't think the specs are too critical. It will run or not. If it don't turn over by hand easily, then you have something wrong. Head spec torque is important as well as the pattern to tighten it up. If you bend the head as you tighten it up, or strip a thread your screwed.
Torque tightness is 220 inch pounds
First step is 75 in lbs, then redo at 150 in lbs then final torque @ 220 in pounds. You need to follow the bolt pattern on the 8 head bolts.
Pattern is this as I will try in type what the pattern is....

1st bolt .... 6 oclock
2nd bolt .... 12 oclock
3rd bolt .... 7 oclock
4th bolt .... 1 oclock
5th bolt .... 11 oclock
6th bolt .... 8 oclock
7th bolt .... 5 oclock
8th bolt .... 9 oclock


#17

R

Rivets

In the manual are the exact valve clearances you will need. Torque pattern should also be in the manual. Also, the torque specs given by tigercat are dry torque, meaning do not use any lube or antisieze.


#18

R

Rickcin

tigercat said:
The B&S manual says once you reach top dead ceter, rotate engine clockwise, as you watch the piston drop 1/4". I don't rotate flywheel 1/4", maybe it works the same, I never checked.

Correct, no thread sealant anywhere, but on the valve cover. Sometimes they leak oil and it will smoke up on the muffler.

I need the "model series" of the engine for exact valve clearance specs. Normally they are around .003-.006 where the exhaust side will be larger by .001

I don't think the specs are too critical. It will run or not. If it don't turn over by hand easily, then you have something wrong. Head spec torque is important as well as the pattern to tighten it up. If you bend the head as you tighten it up, or strip a thread your screwed.
Torque tightness is 220 inch pounds
First step is 75 in lbs, then redo at 150 in lbs then final torque @ 220 in pounds. You need to follow the bolt pattern on the 8 head bolts.
Pattern is this as I will try in type what the pattern is....

1st bolt .... 6 oclock
2nd bolt .... 12 oclock
3rd bolt .... 7 oclock
4th bolt .... 1 oclock
5th bolt .... 11 oclock
6th bolt .... 8 oclock
7th bolt .... 5 oclock
8th bolt .... 9 oclock
Click to expand...

Wow, this is all great information!! Everthing I need to know, now I just need to order the parts and do it! Ironic that the youtube video mechanic turns the flywheel 1/ 4 turn and your research said to drop the piston 1/4 inch. That would be easier since I could measure and mark the flywheel when the head is off to excatly locate the 1/4 inch.

Thanks again, between you and Rivets, I will attempt the repair!!


#19

R

Rickcin

ILENGINE said:
part number 794152 valve overhaul gasket set, includes the head gasket, exhaust gasket, intake gasket, valve stem seal, and the valve cover gasket.
Click to expand...


Great Info - Thanks much!!


#20

S

SeniorCitizen

Rickcin said:
That would be easier since I could measure and mark the flywheel when the head is off to excatly locate the 1/4 inch.
Click to expand...

Works well as long as you make sure the piston is TDC on the compression stroke before you remove the head. After the head is removed you no longer have the rocker lever positions for reference.


#21

R

Rickcin

SeniorCitizen said:
Works well as long as you make sure the piston is TDC on the compression stroke before you remove the head. After the head is removed you no longer have the rocker lever positions for reference.
Click to expand...

Meaning the piston is flush with the top of the block ?


#22

tigercat

tigercat

When you start the job, remove the spark plug and remove the valve cover. Rotate the engine with the bottom pulley. It will rotate with no effort because the plug is removed. Notice the valve and valve springs opening and closing. When both valves are closed insert a screw driver into the spark plug hole. Now carefully rotate the engine until the screw driver rises no further. When valves are both closed and piston is up all the way, you are at top dead center of the engine. When setting the valve lash, rotate the engine a bit more so the screwdriver falls 1/4" (or the piston falls 1/4").
At this exact spot you set the valve clearance with your feeler gauge.
This is as easy as eatting a bowl of ice cream! :licking:


#23

S

SeniorCitizen

Rickcin said:
Meaning the piston is flush with the top of the block ?
Click to expand...

No, not necessarily. The piston is at the top twice in a complete cycle. Once at the end of the exhaust stroke and beginning of the intake stroke. You'll see the exhaust valve just close and the intake valve beginning to open at that point.

The next time it is at the top will be at the end of the compression stroke and beginning of the power stroke. Both the exhaust valve and intake valve will have been closed the full duration of the piston travel during compression and a good portion of the power stroke.

https://www.youtube.com/watch?v=-8cXXjsRg70


#24

R

Rivets

Senior Citizen you are correct, unless the engine has a compression release mechanism. Then you must rotate a little farther, 1/4" down, to make sure that the compression release has been removed.


#25

R

Rickcin

tigercat said:
When you start the job, remove the spark plug and remove the valve cover. Rotate the engine with the bottom pulley. It will rotate with no effort because the plug is removed. Notice the valve and valve springs opening and closing. When both valves are closed insert a screw driver into the spark plug hole. Now carefully rotate the engine until the screw driver rises no further. When valves are both closed and piston is up all the way, you are at top dead center of the engine. When setting the valve lash, rotate the engine a bit more so the screwdriver falls 1/4" (or the piston falls 1/4").
At this exact spot you set the valve clearance with your feeler gauge.
This is as easy as eatting a bowl of ice cream! :licking:
Click to expand...

Confusing to me, but I think I got it. After removing the valve cover, just watch the operation to see when both valves are closed, from that point you want the piston to be dropped 1/4 inch.
So, when I reassemble everything, do the same thing, closed valves then lower the piston 1/4 inch and adjust the valves, correct?

I have an electronic PTO on my Craftsman so the pullys will still turn the crank? Sorry for all of the questions, I need to understand it all 100%!

Thanks again - Rick


#26

tigercat

tigercat

Rickcin said:
Confusing to me, but I think I got it. After removing the valve cover, just watch the operation to see when both valves are closed, from that point you want the piston to be dropped 1/4 inch.
So, when I reassemble everything, do the same thing, closed valves then lower the piston 1/4 inch and adjust the valves, correct?

I have an electronic PTO on my Craftsman so the pullys will still turn the crank? Sorry for all of the questions, I need to understand it all 100%!

Thanks again - Rick
Click to expand...

Correct. On the PTO, The engine spins when you crank it around right? so it will spin by hand too. Without the spark plug there is no compression, so you can roll the engine around with 2 fingers. Find the largest pulley and push it....:smile:


#27

R

Rickcin

tigercat said:
Correct. On the PTO, The engine spins when you crank it around right? so it will spin by hand too. Without the spark plug there is no compression, so you can roll the engine around with 2 fingers. Find the largest pulley and push it....:smile:
Click to expand...

Thanks much! I am waiting for my parts to arrive and some time on a weekend and I will give it a shot. I am looking forward to doing it because if I get it right, it will be satisfying.

I will let you know how I make out. Thanks again - Rick


#28

R

Rickcin

tigercat said:
When you start the job, remove the spark plug and remove the valve cover. Rotate the engine with the bottom pulley. It will rotate with no effort because the plug is removed. Notice the valve and valve springs opening and closing. When both valves are closed insert a screw driver into the spark plug hole. Now carefully rotate the engine until the screw driver rises no further. When valves are both closed and piston is up all the way, you are at top dead center of the engine. When setting the valve lash, rotate the engine a bit more so the screwdriver falls 1/4" (or the piston falls 1/4").
At this exact spot you set the valve clearance with your feeler gauge.
This is as easy as eatting a bowl of ice cream! :licking:
Click to expand...

Okay, today is the day I decided to change the head gasket and I now see a bunch of what looks like oil on this black part, which I believe to be a fuel pump?

The reason I am thinking it is the head gasket is because it fialed about 4 years ago and the sympton was it was burning oil nad ocassionally back firing.

Perhaps the head gasket has not failed again but it is using oil and I see some blue smoke when engaging the mower deck.

Wondreing what to do, thanks - RickIMG_1926.jpg


#29

R

Rickcin

tigercat said:
When you start the job, remove the spark plug and remove the valve cover. Rotate the engine with the bottom pulley. It will rotate with no effort because the plug is removed. Notice the valve and valve springs opening and closing. When both valves are closed insert a screw driver into the spark plug hole. Now carefully rotate the engine until the screw driver rises no further. When valves are both closed and piston is up all the way, you are at top dead center of the engine. When setting the valve lash, rotate the engine a bit more so the screwdriver falls 1/4" (or the piston falls 1/4").
At this exact spot you set the valve clearance with your feeler gauge.
This is as easy as eatting a bowl of ice cream! :licking:
Click to expand...

I did it and it works!!!! Thanks to your help and the youtube video. After getting done, it would not start. I pulled the valve cover off, re-adjusted the valves and it still would not start. This time I used my head, I removed the vlave cover and turned the flyweheel to watch the valves move and th eintake valve was not moving at all. I play around until I found the sweet spot where it moved, then reassembled adjusted and it started right up.
The head torque called for 220 inch pounds and I went somewhere around 20 foot pounds so I hope thta is good for the long haul.

I feel great that I was able to make th erepair myslf and save $220 that Sears would have charged.

Thanks again - Rick


#30

tigercat

tigercat

20 foot pounds will be fine.

Congrats! :thumbsup:


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