LS1 vs LS6 exhaust manifold gaskets
05-16-2005, 05:46 PM
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LS1 vs LS6 exhaust manifold gaskets I replaced the headers on my LS1 engine (from a 2002 Pontiac Firebird) with shorter headers from a Corvette of a similar vintage (so I think LS6). The new headers have provision for EGR (which I have had blocked off). The headers were installed using the original LS1 metal gaskets.
However, where the EGR port comes through the block side of the headers it is not covered by the LS1 gaskets (as the original headers didn't have the EGR provision) so the exhaust is blowing massively from the top of each gasket.
Can someone post a picture of the LS6 gasket that should block off this port. A part number would help too.
I've attached a picture of my gasket to demonstrate what I mean...
However, where the EGR port comes through the block side of the headers it is not covered by the LS1 gaskets (as the original headers didn't have the EGR provision) so the exhaust is blowing massively from the top of each gasket.
Can someone post a picture of the LS6 gasket that should block off this port. A part number would help too.
I've attached a picture of my gasket to demonstrate what I mean...
05-17-2005, 07:20 AM
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I didn't say it came off the head gasket. The EGR port goes through to the rear of the headers (manifold) where it would normally be blocked off by the gasket. However, on the LS1, the gasket doesn't cover the hole
05-25-2005, 05:59 AM
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What is the hole in my Corvette manifolds that has been blocked off by a cover plate? I thought that was EGR? Perhaps it is AIR and I am confused. Looking at the actual gaskets I need (on page 103 of the Chevy LS1/LS6 performance book) the lower gasket has an extra flange that will cover this hole.
05-25-2005, 11:17 AM
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Not sure how it is on the Corvette manifolds, but on the f-body manifolds, the AIR tubes are right on the top of each. The EGR is down low on the pass side only. Block off plates are available for all. Hope this helps.
05-25-2005, 12:28 PM
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I think you are right, it is the AIR tube. The hole to the outside is blocked off satisfactorily, but where it goes through to the back (i.e. the block side of the manifold) it is uncovered by the gasket and blowing quite strongly into the engine compartment.
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05-25-2005, 04:57 PM
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Well, seeing as LS1-6 Corvettes never had EGR it has to be an AIR fitting. Any GM dealer should have AIR gaskets instock they're a couple dollars for a pack of 4 or 6. This is for the outside flange.
If you're getting a leak from between the flange of the header and the head, your gasket may not be on correctly or you need new ones or your flange is warped.
Pictures please of this hole in question.
If you're getting a leak from between the flange of the header and the head, your gasket may not be on correctly or you need new ones or your flange is warped.
Pictures please of this hole in question.
05-25-2005, 07:04 PM
#9
Originally Posted by robin427
I think you are right, it is the AIR tube. The hole to the outside is blocked off satisfactorily, but where it goes through to the back (i.e. the block side of the manifold) it is uncovered by the gasket and blowing quite strongly into the engine compartment.
05-31-2005, 06:15 AM
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I've already blocked the AIR hole on the outside of the manifolds, and they are not leaking. I've attached a picture of the two gaskets in question - the one at the top is what I have, and the one at the bottom is the one I need. You will notice the extra flange that will cover the AIR hole where it comes through to the back of the manifold.
05-31-2005, 08:31 AM
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Robin I know what you are talking about I am doing the same thing, just figured that out this weekend. I was just going to get the correct gaskets and assume they will block this. It appears to be a cross over area between the 2 inner exhaust ports. I think the correct gasket will work. (I hope)
You show the gasket in the picture can you not find them?
Dave
You show the gasket in the picture can you not find them?
Dave
05-31-2005, 08:47 AM
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I've managed to track one down. I'm in the UK so ordering parts is a little difficult as GM don't sell the LS1 over here (although I think the Vauxhall Monaro uses an LS6 or similar)
06-09-2005, 06:57 AM
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Here is a photo of my new gasket (top) and old gasket (bottom). I've also included a picture of the port in question that goes through to the back of the manifolds and is covered by the extra flange:
