LS9 Headgasket - 4.130?
LS9 Headgasket - 4.130? Has anyone ever opened up the LS9 head gasket bore just a smidge. I have a set laying around that measured out at a 4.090 bore and a 4.100 bore motor that I'm putting together.
Normally, I would order and use a 4.130 bore cometic, but (like everything) those are back-ordered until eternity and it doesn't look like it would be that difficult to take the LS9 gaskets down to the local machine shop and have the bore opened up smidge. I also just like the GM gasket over the cometic - would be nice to use them.
Bad juju if I have them 'massaged' open to a 4.130? Does it cause any issues with the MLS system - has anyone done it?
18(ish) psi on an LQ9 head and sleeved block via a D1.
Normally, I would order and use a 4.130 bore cometic, but (like everything) those are back-ordered until eternity and it doesn't look like it would be that difficult to take the LS9 gaskets down to the local machine shop and have the bore opened up smidge. I also just like the GM gasket over the cometic - would be nice to use them.
Bad juju if I have them 'massaged' open to a 4.130? Does it cause any issues with the MLS system - has anyone done it?
18(ish) psi on an LQ9 head and sleeved block via a D1.
Last edited by NoGo; Oct 7, 2021 at 10:15 PM.
I cant even imagine how you could open up the bore on a multi layered gasket, and end up
not having a bur along the edges. Out of stock is killing everybody, I dread a new project.
not having a bur along the edges. Out of stock is killing everybody, I dread a new project.
It seems like you are firing off advice here without actually knowing how these look....
I made plenty of these gasket layers, and the only time an edge was rolled over was if the cuts got dull. We tried to throw all of those out for recycling. There is no reason a skilled machinist, (or a random idiot) could not bore them out. Elringklinger makes the MLS gaskets for General Motors. When their stamping presses break down they use the place I work at to keep production flowing. I have made or supervised the making of hundreds of thousands of them over the years.
I made plenty of these gasket layers, and the only time an edge was rolled over was if the cuts got dull. We tried to throw all of those out for recycling. There is no reason a skilled machinist, (or a random idiot) could not bore them out. Elringklinger makes the MLS gaskets for General Motors. When their stamping presses break down they use the place I work at to keep production flowing. I have made or supervised the making of hundreds of thousands of them over the years.
I'll take them to the machine shop and see what they can do. Let me know if there is anything special I need to pass on to the machinist.
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ls7 head gaskets can be used on engines from a 4.125 to a 4.140 (or 4.150) bore.
have personally used them on a 4.125 and a 4.135 bore with no issues.
how would bore size of gasket impact compression in a meaningful way? Quench I could see. But not tracking compression.
sorry man. Still not tracking.
ls7 head gaskets can be used on engines from a 4.125 to a 4.140 (or 4.150) bore.
have personally used them on a 4.125 and a 4.135 bore with no issues.
how would bore size of gasket impact compression in a meaningful way? Quench I could see. But not tracking compression.
ls7 head gaskets can be used on engines from a 4.125 to a 4.140 (or 4.150) bore.
have personally used them on a 4.125 and a 4.135 bore with no issues.
how would bore size of gasket impact compression in a meaningful way? Quench I could see. But not tracking compression.
It does reduce the compression some and if you don't believe me then check it out on the Wallace Racing Compression calculator when determining compression. I've had 4.185 diameter gaskets and switched over to a 4.150 diameter gasket on my LSX427. The LS370 which is a 4.030 bore originally had LS9 head gaskets which was 4.10 diameter .054 gasket now has a 4.05 bore .045 thick gasket. My guess is the bore OP is working with is a 4.065 or 4.085 cylinder bore which is why he's looking for a 4.130 diameter head gasket and wouldn't like the idea of an LS7 gasket which is .075 thick 4.150 diameter.
The ls9 gasket he is looking at machining has a thickness of 54 vs 51 for the ls7 gasket based on the GM specs I have seen.
just seems that a ls7 gasket would be the easy fix with a negligible change in compression.
The issue is that I have these LS9 laying around (so free...) and the usual set I get is back ordered until at least December.
I've been waiting on a 3.23 gear set since February, so not looking to get into that mess with a head gasket- looking to see if I can just make what I have laying around work.