Briggs and Stratton head problem

[charleneje]

I own a Craftsman YT3000 riding mower numbers on valve cover is 331977 0010 G1 130502ZD That keeps blowing head gaskets I am in process of replacing head gasket for the fourth time. I tried gluing 120 grit wet and dry to a piece of glass I put that on my table saw bed to make sure it was on a flat surface I then tried to sand the head surface flat by doing constant figure eights on it and the area where the bolt holes is showed I had been sanding I kept on doing that but it never improved almost as if the area that was touching the wet or dry was either terribly dished or aluminum is growing, I have replaced the paper three times in case it had got worn out, should I be using rougher grit or am I wasting my time?. Any advice would be appreciated.

 

[charleneje]

I own a Craftsman YT3000 riding mower numbers on valve cover is 331977 0010 G1 130502ZD That keeps blowing head gaskets I am in process of replacing head gasket for the fourth time. I tried gluing 120 grit wet and dry to a piece of glass I put that on my table saw bed to make sure it was on a flat surface I then tried to sand the head surface flat by doing constant figure eights on it and the area where the bolt holes is showed I had been sanding I kept on doing that but it never improved almost as if the area that was touching the wet or dry was either terribly dished or aluminum is growing, I have replaced the paper three times in case it had got worn out, should I be using rougher grit or am I wasting my time?. Any advice would be appreciated.

Sorry I forgot to put on there it is the engine that is prone to blowing head gaskets and it is a Platinum 21 HP engine I bought it beginning of 2014 its been a lemon ever since I bought it Sears sent a mechanic to my house three times to fix things that broke within the first 90 days each time they knew exactly what was wrong because they sent parts to me for the mechanic to install. After it quit again I parked it and didn't use it for a couple years I used the one I wanted to replace but luckily hadn't sold

 

[ILENGINE]

I would be checking the block for warpage also. Wouldn't be the first Briggs OHV that has a warped head mating surface on the block that I have seen.

 

[Rivets]

Never had any luck trying to smooth an OHV head by hand sanding. 90% of the time I use a stationary disc sander and 10% take it to my machinist. My question to you is, when you torque the head bolts are they dry and you are using a three step torque sequence? Also as IL says, check the block. If you don’t have a manual this one will provide you with the torque procedure. https://drive.google.com/file/d/0B6NaqjIxWV1ybEN0LWo3azl6OUU/view

 

[charleneje]

Never had any luck trying to smooth an OHV head by hand sanding. 90% of the time I use a stationary disc sander and 10% take it to my machinist. My question to you is, when you torque the head bolts are they dry and you are using a three step torque sequence? Also as IL says, check the block. If you don’t have a manual this one will provide you with the torque procedure. https://drive.google.com/file/d/0B6NaqjIxWV1ybEN0LWo3azl6OUU/view

Thanks for the link thats a really useful manual

 

[bertsmobile1]

On the few that just refuse to seal I use copper head gaskets bought from Lanni@cppergasketsUS.
He has the profiles on hand & can cut them in any std USA gauge thickness .
Hydro locking is a big cause of head gaskets blowing.
After that over heating softening the block
Put a small counter sink on every bolt hole to prevent the threads pulling & giving you false readings