gasket compression
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gasket compression Can I put a cometic .36 or .30 gasket on my stock ls6 engine. I want to raise my compression to like 11.1 or 11.3. I know I can do it shaving the heads but can i do it with the gaskets only?
No, the pistons usually stick out the hole .005-.010
Using a .030 or .036 gasket will give you too tight of a quench.
For example a .036 gasket minus .007 piston out of the hole and you get .029 quench
You want .035-.045 quench, which is recommended by most builders
Using a .030 or .036 gasket will give you too tight of a quench.
For example a .036 gasket minus .007 piston out of the hole and you get .029 quench
You want .035-.045 quench, which is recommended by most builders
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Quench is about piston to head contact not PTV contact. Things change size with temperature, pistons rock in the bore, there is rod bearing to crank journal clearance the rod can move around some with. Point being that just because measuring everything cold on the stand static shows the piston wont hit the head doesn't mean it will all still clear running.
Basically bare minimum I have ever heard of on a street SBC of any sort was about .030 with most considering .035 to be a bit safer.
If you really think everyone is wrong though feel welcome to enlighten us with your experiment, just understand that the reason we want this much clearance is because of how everything moves/stretches/expands/rocks in operation and that letting the piston contract the head would likely do damage.
Basically bare minimum I have ever heard of on a street SBC of any sort was about .030 with most considering .035 to be a bit safer.
If you really think everyone is wrong though feel welcome to enlighten us with your experiment, just understand that the reason we want this much clearance is because of how everything moves/stretches/expands/rocks in operation and that letting the piston contract the head would likely do damage.
Thread Starter
On The Tree
Joined: Mar 2013
Posts: 110
Likes: 14
From: Puerto Rico
Thread Starter
On The Tree
Joined: Mar 2013
Posts: 110
Likes: 14
From: Puerto Rico
Quench is about piston to head contact not PTV contact. Things change size with temperature, pistons rock in the bore, there is rod bearing to crank journal clearance the rod can move around some with. Point being that just because measuring everything cold on the stand static shows the piston wont hit the head doesn't mean it will all still clear running.
Basically bare minimum I have ever heard of on a street SBC of any sort was about .030 with most considering .035 to be a bit safer.
If you really think everyone is wrong though feel welcome to enlighten us with your experiment, just understand that the reason we want this much clearance is because of how everything moves/stretches/expands/rocks in operation and that letting the piston contract the head would likely do damage.
Basically bare minimum I have ever heard of on a street SBC of any sort was about .030 with most considering .035 to be a bit safer.
If you really think everyone is wrong though feel welcome to enlighten us with your experiment, just understand that the reason we want this much clearance is because of how everything moves/stretches/expands/rocks in operation and that letting the piston contract the head would likely do damage.
Where are the pistons sitting now? As has been said on these motors they are usually above the deck a little. HAVE TO know that before you can go ordering a gasket under say .050. I just say .050 because the pistons are unlikely to stick out enough to cause too tight a quench with a gasket that thick, but it is possible you could be on the ragged edge of unsafe if you ordered a .040 and the piston happens to be .01 up. If it happens to be up .005 then a .040 gasket would be great.
Thread Starter
On The Tree
Joined: Mar 2013
Posts: 110
Likes: 14
From: Puerto Rico
Where are the pistons sitting now? As has been said on these motors they are usually above the deck a little. HAVE TO know that before you can go ordering a gasket under say .050. I just say .050 because the pistons are unlikely to stick out enough to cause too tight a quench with a gasket that thick, but it is possible you could be on the ragged edge of unsafe if you ordered a .040 and the piston happens to be .01 up. If it happens to be up .005 then a .040 gasket would be great.
Thread Starter
On The Tree
Joined: Mar 2013
Posts: 110
Likes: 14
From: Puerto Rico
Thread Starter
On The Tree
Joined: Mar 2013
Posts: 110
Likes: 14
From: Puerto Rico
i think you can mill them about 58cc or 59cc. Since the manifold is not touching in the bottom like the Old sbc
A .030" or .036" gasket on a stock bottom end is not a smart move due to piston to head clearance issues.
A .040" gasket would be as close as I would go.
And you can mill the stock heads .040"-.045" before you start to have some alignment issues. .030" is plenty however.
A .040" gasket would be as close as I would go.
And you can mill the stock heads .040"-.045" before you start to have some alignment issues. .030" is plenty however.