.040 Head gasket=more HP?
Launching!
Joined: Dec 2003
Posts: 251
Likes: 2
From: Portland OR
Originally Posted by Spinmonster
A half point is near 7hp and 10rwtq. You would see that with a .033 gasket which is a best bet for your stock cam and 93 octane.
To answer your original question, with a .040 it should be 4-5hp and 7tq.
To answer your original question, with a .040 it should be 4-5hp and 7tq.
TECH Enthusiast
Joined: Sep 2003
Posts: 730
Likes: 66
Originally Posted by 71CamaroLS1
.033 gasket will leave only about .026 piston/head clearance cold - IMO, not enough! LSx motors seem to be able to get away with tighter piston/head clearance than old school motors, but still ... If it was me, I wouldn't go for a smaller gasket than the .040, leaving a .033 quench distance - plenty tight, and lower risk of engine damage.
Lingenfelter stated .020 quench was safe on LSx's.
Cartek sends every H/C package out with a .030 gasket.
Show me a failure with .020 quench to support your opinion. While your opinion has as much value as anyone else's, there is no data to support it. Fortunately you dont have to go so close since there are options for maximizing compression so running a .040 gasket plus some milling is fine. I am just pointing out that the quench requirements you state arent fact. There are many cars out there running a .030 gasket and doing fine.
Launching!
Joined: Dec 2003
Posts: 251
Likes: 2
From: Portland OR
Spin, I think you're very probably right. Most of my experience is with old style small and big blocks, and in an old style iron small block anything below about .030 quench is asking for piston/head collision and serious damage. But there are some factors that are different in at least some versions of the LSx.
For one thing, the block is aluminum, which will create .006 or more of additional clearance when hot. Also, the stock hyper pistons have a lower coefficient of expansion than forged, and also transfer less heat, so the pistons will not grow as much under operation. And the piston/wall clearance is tighter, meaning less piston rock.
But there are a number of variables impacting minimum safe quench, and if you're running a different short block than the factory LS1, LS2, or LS7, for instance an iron block with forged pistons and slightly looser bearing clearances, .020 will almost certainly not be safe.
Also, if folks are using very tight quench, it's even more important than usual to make sure the engine is fully warm before running high revs ...
For one thing, the block is aluminum, which will create .006 or more of additional clearance when hot. Also, the stock hyper pistons have a lower coefficient of expansion than forged, and also transfer less heat, so the pistons will not grow as much under operation. And the piston/wall clearance is tighter, meaning less piston rock.
But there are a number of variables impacting minimum safe quench, and if you're running a different short block than the factory LS1, LS2, or LS7, for instance an iron block with forged pistons and slightly looser bearing clearances, .020 will almost certainly not be safe.
Also, if folks are using very tight quench, it's even more important than usual to make sure the engine is fully warm before running high revs ...
I was told, by a very reputable vendor, that .034 quench might be a "little tight" on a stock short block. So I went with an .045 gasket since my pistons are .006 out of the hole. He also mentioned the importance of operating temperature, especially oil temp...
TECH Enthusiast
Joined: Sep 2003
Posts: 730
Likes: 66
Originally Posted by chuckyt1
I was told, by a very reputable vendor, that .034 quench might be a "little tight" on a stock short block. So I went with an .045 gasket since my pistons are .006 out of the hole. He also mentioned the importance of operating temperature, especially oil temp...
I have said it before and agree, that a .030" gasket is just too tight with a piston 6 thou out of the hole. .040" is what we sell and send out with MOST every setup that leaves here (again, it's not written in stone, but 33-35 thou quench seems to be the sweet spot on these motors from what we've seen).
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