LS3 Headgasket Q
Thread Starter
TECH Regular
Joined: Jun 2021
Posts: 497
Likes: 148
From: Shlumpt, TX
LS3 Headgasket Q Boring an LS3 out to 4.07 am I able to use a stock LS3 head gasket? Using L92 heads, no milling. Pistons I am looking at are JE 311981. I do not believe I will have PTV issues with this setup.
Just wondering if I can use the stock LS3 gaskets in terms of bore size?
EDIT: I believe that the LS3 gaskets have a bore of 4.085? Can anyone confirm that as well?
Just wondering if I can use the stock LS3 gaskets in terms of bore size?
EDIT: I believe that the LS3 gaskets have a bore of 4.085? Can anyone confirm that as well?
Thread Starter
TECH Regular
Joined: Jun 2021
Posts: 497
Likes: 148
From: Shlumpt, TX
Thanks @Che70velle
Another question I have is, what is the tolerance for the gasket being larger than the cylinder bore? I figure you don't want it a whole hell of a lot bigger but just curious if there was some guideline to follow.
I think you are right though the LS9 head gasket should work.
Another question I have is, what is the tolerance for the gasket being larger than the cylinder bore? I figure you don't want it a whole hell of a lot bigger but just curious if there was some guideline to follow.
I think you are right though the LS9 head gasket should work.
Thanks @Che70velle
Another question I have is, what is the tolerance for the gasket being larger than the cylinder bore? I figure you don't want it a whole hell of a lot bigger but just curious if there was some guideline to follow.
I think you are right though the LS9 head gasket should work.
Another question I have is, what is the tolerance for the gasket being larger than the cylinder bore? I figure you don't want it a whole hell of a lot bigger but just curious if there was some guideline to follow.
I think you are right though the LS9 head gasket should work.
All headgaskets are going to naturally sit a tad big on the bore size, while properly fitting the chamber, unless it’s a custom build and the cylinder head guy hand blends the chamber to accommodate a particular headgasket that’s usually going to be a custom Cometic or the like. So your basically going to have a tiny space around the top of the cylinder to deal with, and there is a formula to figure the area (along with crevice area above the rings if your really picky) for compression numbers.
Formula is rD*π/4*(bD^2-pD^2)
rD=ring depth…top of piston to top of ring
bD=bore diameter
pD=piston diameter above the top ring
Here’s a link to a easy online plug-n-play crevice volume finder.
https://www.vcalc.com/wiki/KurtHeckman/crevice+volume
edit…we should build a page for hard to find formulas and make a sticky…I’ll work on this.
