Craftsman LT1000 with a Briggs & Stratton 31G777-0167E1 engine

I have seen that engine run fine and not smoke running but blow a little smoke on starting and then a little oil and vapor out the breather tube. Prob was blown head gasket but you couldn't see a problem with the gasket. Looked fine. New gasKet and no smoke at startup or oil out the dipstick tube. Before splitting the crankcase i would just try a new head gasket. If the bore looks good i doubt rings are the problem.
 
If you want a reuseable head gasket go to CoppergasketsUS and get one of Lanni's solid copper head gaskets .
Otherwise replace it unless you want to practice pulling engines apart
 
Rivets said:
Just my opinion, but when trying to reuse a head gasket on a Briggs engine you are only asking for trouble. Today’s gaskets are not like the ones produced 20 years ago and I never even think about reusing one.
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I don’t reuse head gaskets. Not even the ones from 20-30 years ago. I don’t trust gaskets that compress when torqued will ever seal the same as they did the very first time.
 
make sure the exhaust is open and free, and does not have any carbon build up on baffles or screens if there is a spark arrester on it. If the exhaust is slightly plugged it will raise combustion pressures and possibly cause blowby. You've checked the breather but check it again. If it is open to the air cleaner, which most dump into then pressure should not build up. Likewise, if there is too high an oil level or gasoline in the oil that can cause those symptoms too. A blown head gasket will show just a slight darkening in the affected area(s).
 
sgkent said:
make sure the exhaust is open and free, and does not have any carbon build up on baffles or screens if there is a spark arrester on it. If the exhaust is slightly plugged it will raise combustion pressures and possibly cause blowby. You've checked the breather but check it again. If it is open to the air cleaner, which most dump into then pressure should not build up. Likewise, if there is too high an oil level or gasoline in the oil that can cause those symptoms too. A blown head gasket will show just a slight darkening in the affected area(s).
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Thanks for your input. I have checked all of this - the muffler was the first thing to come off and get looked at. Definitely not plugged. Pics attached of the parts. The head gasket has a couple small chips out of the edge in the area where they burn through, but this happened when I pulled it off. That costing is super flaky around the edges it seems. I don’t see solid evidence of the gasket failing to the degree it would need to to cause this, but maybe the gasket is permeable between the layers... I have to upload my photos to my photo host site due to their size. I’ll have these uploaded later this morning for all to see.
Thank you to all who have responded. I’m sure a forum newbie with zero posts asking a silly question gets an eye roll or two. Usually the line I see given is “you should have used the forum search before making a new thread”. Thank you for not scolding me. :)
I have been an engine guy for 25+ years. My smallest engine I own is .049ci.. I know what I’m doing most of the time, and when I don’t, I’m pretty darn stubborn to ask for help. Thank you everyone.
 
Here are some photos. The edges of the head gasket are pretty flaky - which I would expect for a 22 year old engine. The little specks chipped off beteeen the bore and lifter/pushrod valley while handling it after removal. I don’t see any evidence of combustion residue outside of the bore. Maybe you see something I don’t.




 
Those areas between the cylinder and push rod are normal blown head damage. And I replaced quite a few that fail leak down tests that look like that. Also the side that is darker is usually a leaky area too.
 
This is one time that Star and I agree, there is evidence of a blown gasket between the cylinder and valve train galley. I also see the dark surface of the gasket, opposite the valve galley, indicating leaking gasket.
 
sgkent said:
make sure the exhaust is open and free, and does not have any carbon build up on baffles or screens if there is a spark arrester on it. If the exhaust is slightly plugged it will raise combustion pressures and possibly cause blowby. You've checked the breather but check it again. If it is open to the air cleaner, which most dump into then pressure should not build up. Likewise, if there is too high an oil level or gasoline in the oil that can cause those symptoms too. A blown head gasket will show just a slight darkening in the affected area(s).
Click to expand...
Thanks for your input. I have checked all of this - the muffler was the first thing to come off and get looked at. Definitely not plugged. Pics attached of the parts. The head gasket has a couple small chips out of the edge in the area where they burn through, but this happened when I pulled it off. That costing is super flaky around the edges it seems. I don’t see solid evidence of the gasket failing to the degree it would need to to cause this, but maybe the gasket is permeable between the layers...
StarTech said:
Those areas between the cylinder and push rod are normal blown head damage. And I replaced quite a few that fail leak down tests that look like that. Also the side that is darker is usually a leaky area too.
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Fair enough! I’ll pass on the rings for now and just replace the head gasket. I’ll check the head for flatness.
 
I have a stupid question that I already know the answer to, but I’m going to ask it anyway. :D. Is there any use/benefit in using a little gasket sealer between the bore and lifter valley to prolong the gasket from leaking there?
 
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