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FarmGeezer said:

I have a verticle V-Twin 20 HP. Model # 351777-0036-01. It was pushing raw gas out of the carb and running only on 1 cyl. It's got a lot of hard hrs. on it so I pulled the heads. Nothing definitive but I'm doing a valve job. It's ready to go back together and I need the head bolt torque if possible. It has the thin metal head gaskets and since there was no damage or kinks in them I'm going to clean them up and use copper coat gasket sealer. the stem seals will be replaced and I'll make my own rocker gaskets.

Regards,

FarmGeezer

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Don't even think of refitting the old gaskets.
You have a 99% chance they will not seal properly
The gaskets are about $ 5.00 each

bertsmobile1 said:

Don't even think of refitting the old gaskets.
You have a 99% chance they will not seal properly
The gaskets are about $ 5.00 each

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I agree with this, but I have in the pass used old head gaskets over when I couldn't get a new one and have to say never had a problem doing so.

reynoldston said:

I agree with this, but I have in the pass used old head gaskets over when I couldn't get a new one and have to say never had a problem doing so.

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That could sometimes be done with the old flathead engines. Trying to do it with today's OHV engines is very risky.

I can send you a Service Manual (Overhaul Manual) for your engine IF you like. Address below, put in proper format and remind me engine model number and what you want.

Walt Conner
wconner5 at frontier dot com

FarmGeezer said:

I used the old head gaskets and torqued the heads to 160 in. lbs.. Seems to run fine. I cleaned the old gaskets with a xtra fine scotch pad and used copper coat gasket spray. I made rocker cover gaskets from some gasket paper I got at the local parts store. Runs good , plenty of power and no oil leaks.

Regards,

FarmGeezer

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Most be that the head bolts can't be very large. 160 in lbs. because that is only a little less then 13.5 ft. lbs. Just doesn't seem very tight for head bolts? but I don't know the size. Runs good without any oil leaks can't get any better then that.

FarmGeezer said:

Well...it has a cast iron bore but the block and heads are aluminum. The head bolts are fine thread and I did not have the torque specs ( which was my original request that I got no answers for ) I got tired of trying to navigate thru the B&S web site ( it's a joke imho ) so I relied on a general torque spec chart I have for outboard engines ( aluminum blocks ) . The head bolts are 5/8 so I used the SWAG method after referring to the chart. It's not rocket science or a small block Chevy...

Regards,

FarmGeezer

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The very first thing is we need the make and model of the engine you are working on. This is the reason no one give you any specs. I am going to take a guess here and say you have metric bolts??? To get a torque specs we will need the proper bolt size not the wrench size. If you have 5/8 fine thread bolts holding that head down its something I have never come across in my years in the trade and you would be looking at 150 ft. lbs. or better. By any chance do you have a 20HP Briggs and Stratton in this mower? Toque bolts in two increments, first 200 in. lbs. and then 370 in lbs. This is just guessing as to what you have.

I have used the old head gaskets over in a pinch as I said. I just use the number 3 Permatex for the sealant. Nothing wrong with the way you did it. I am doing this work for customers and they expect quality work so I always use new gaskets when ever I can. Sometimes when on older equipment I can't find replacement parts I will have to use the old parts over again like head gaskets and make some of my gaskets. I would re torque your head bolts if I was you because you will end up blowing out a head gasket just when you need your mower the most and working it hard.

I'll take that advise to heart and re torque the gaskets. Thanks for your help.

Regards,

FarmGeezer

The very first thing is we need the make and model of the engine you are working on. This is the reason no one give you any specs. I am going to take a guess here and say you have metric bolts??? To get a torque specs we will need the proper bolt size not the wrench size. If you have 5/8 fine thread bolts holding that head down its something I have never come across in my years in the trade and you would be looking at 150 ft. lbs. or better. By any chance do you have a 20HP Briggs and Stratton in this mower? Toque bolts in two increments, first 200 in. lbs. and then 370 in lbs. This is just guessing as to what you have.

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Not meaning to nit pick but the 150 ft lbs is of course 150 inch pounds which should be obvious from the latter two figures which are both inch pounds

bertsmobile1 said:

Not meaning to nit pick but the 150 ft lbs is of course 150 inch pounds which should be obvious from the latter two figures which are both inch pounds

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I have no idea what you are talking about here. I got my information off a torque chart. A 5/8 bolt is what I would call a large bolt for a lawn mower engine head bolt. They would use something like that on a large diesel engine head bolt. For a standard steel coarse thread 5/8-11 bolt grade 5 bolt my chart calls for 154 foot pounds of torque not inch pounds but if you need it in inch pounds that will come to 1,848 inch pounds.

https://www.briggsandstratton.com/us/en/support/manuals/results?NTT=351777-0036* engine operators manual & parts list

http://rich.homeunix.com/gravely/pro16/272144 Vanguard Twin Cylinder OHV BRIGGS & STRATTON.pdf engine service repair manual. Head bolt torque is 165 inch lbs. page 166 in manual.

reynoldston said:

I have no idea what you are talking about here. I got my information off a torque chart. A 5/8 bolt is what I would call a large bolt for a lawn mower engine head bolt. They would use something like that on a large diesel engine head bolt. For a standard steel coarse thread 5/8-11 bolt grade 5 bolt my chart calls for 154 foot pounds of torque not inch pounds but if you need it in inch pounds that will come to 1,848 inch pounds.

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From your previous post

If you have 5/8 fine thread bolts holding that head down its something I have never come across in my years in the trade and you would be looking at 150 ft. lbs. or better. By any chance do you have a 20HP Briggs and Stratton in this mower? Toque bolts in two increments, first 200 in. lbs. and then 370 in lbs. This is just guessing as to what you have.

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The first number you quote is 150 ft lbs
You then say to torque to 370 inch pounds in two steps.

Me thinks the numbers you have looked up were for fine threads into cast iron or steel.
Threads in die cast aluminium will shear out way before you torque a bolt to 150 ft lbs and that is irrespective of the thread size or form.

As a rule of thumb bolts into alloy should never be torqued past 45 ft lbs ( 540 inch lbs )

Me thinks the numbers you have looked up were for fine threads into cast iron or steel.
Threads in die cast aluminium will shear out way before you torque a bolt to 150 ft lbs and that is irrespective of the thread size or form.

Yes I agree on this, but the OP was way off on his bolt sizes. First of all he was working with metric not SAE. You might have a lot of different things down under that I never come across but when he was talking about 5/8 size head bolts the first thing that come to me was it was something I have never seen in a lawn mower. I have been in the trade too long to say it isn't true because anytime you do it backfires into your face when you don't know what. As I said when I did give any torque specs I was just making a guess. 1 ft. lb. is 12 in lbs. is the way I always worked with it. 12 inches to a foot over here in the USA.

Well I got the gasket kit today ( $50.00 ). Did a valve job and everything is ready for reassembly. My heads had valve guide seals on both valves. The kit only comes with 2 . I assume they go on the intake valve guides. I plan on reassembly on Thursday ( my day off ). Could someone please advise me on the placement of the new Valve stem seals.

Thanks,

FarmGeezer

FarmGeezer

Read this section, it should help you: http://rich.homeunix.com/gravely/pro16/272144 Vanguard Twin Cylinder OHV BRIGGS & STRATTON.pdf

Tom