I have an exhaust leak that I am unable to locate. I have tried everything  else so next is manifold gaskets. My understanding is that the 75 L48 did not have manifold gaskets installed during the factory build up. None the less, mine appears to have gaskets.

Is there one gasket that is better than the other? Any tips on the installation? My engine is pure stock. I think I will also do valve cover gaskets at the same time. What's the best set to get?

Thanks,

Scott
ranger32008-11-11 13:37:08

Check this copper exhaust manifold gasket:   http://www.ecklers.com/product.asp?pf_id=36989&dept_id=159

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No pun intended on the "copper"

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I like the cork/rubber composition. They can be used many times over:  http://store.summitracing.com/partdetail.asp?part=MRG%2D179&view=32&N=700+150+4294840140&appfilter=1#Application corvette440hp2008-11-12 15:40:45

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You can also go with this:   http://store.summitracing.com/partdetail.asp?autofilter=1&part=FEL%2DMS9275B&N=700+307953+4294908216+4294925067+4294840140+115&autoview=sku

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Thanks for the quick replies Larry. I want to do this next weekend of I get the parts. I like the look of the copper exhaust gaskets. Seems like an easy day project.

Scott
ranger32008-11-11 17:40:49

Scott,

Yea Kevin, true duals/chambered exhaust. I checked from the manifolds back today. Even dropped the down tubes from the manifolds. Everything else looks great including the donuts. I am not even sure that the manifold gaskets are bad, but there is nothing else left except a cracked manifold and I even looked for that with an inspection mirror. It is a minor leak. sort of a like lifter noise but definitely exhaust. It is enough to annoy the crap out of me so I have to find the problem. I can't enjoy driving it like this. Thanks for the reply.

Scott

Hey Scott,

Scott, make sure the head and manifold surfaces are as clean as you can get em befor bolting up with the new gaskets. If you can get then disconnected from the pipes, I'd wire wheel the manifolds.

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Thanks Paul...will do.

Scott

Also, make sure it's not a cracked manifold...they can be hard to detect at times, depending on the location of the crack.
IMHO, the best exhaust gaskets you can use are header gaskets, believe it or not. Get some name brand header gaskets, and soak them in water for a few minutes(2-3 minutes). Then bolt them on before they dry out. Tighten them down really snug. Being wet will allow them to compress around the exhaust ports. Once you start it up, and the heat from the exhaust dries them out, they'll be there, with no leaks ever, unless the bolts back out for some reason. I'll usually put a wrench back on them after running it for 15-20 minutes, just to be sure they're tight. Werks every time fer me...

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Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

I agree with Adam.  Wet header gaskets from a brand name source work best.  They don't look exactly stock, in case that is a problem.  I would suggest that before you take anything apart, you stuff a rag in the end of the exhaust so it creates more back pressure.  You might have better luck finding your leak.

Larry

Thanks Joel and Larry, Vettespecialties. I have alredy tried the rag trick. It made no difference. I will do a thorough inspection of both manifolds once they are removed. I certainly don't see any obvious cracks. Thanks to all for the excellent suggestions. If the weather is good this weekend, I will get er done.

Scott

If you take the mirror, and check with the vette running it will sometimes be enough to fog up the mirror, help to find cracks.

Or, do the rag trick, but dump a little tranny fluid thru the carb....and watch where the smoke comes out...

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Joel Adams
C3VR Lifetime Member #56    
My Link


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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Well, I got the passenger side exhaust manifold gasket and valve cover gasket done tonight. I used the new Mr. Gasket copper exhaust gasket with the raised sealing area. I used a new style rubber valve cover gasket by Fel-Pro. The passenger side should be the most difficult because the AC compressor had to be moved aside. I'll start the driver's side in the morning. Thank you all for your great suggestions.

Scott
ranger32008-11-14 17:31:55

Scott, that's great, I'm sure it'll work out for you

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I completed the project this morning. New exhaust manifold gaskets and valve cover gaskets. No more leaks. Took her for a ride, then re-torqued everything. Sounds like it should and no more smell of leaking oil on the manifolds. Back like it should be. Thanks to all.

Scott

It will be nice not having that oil smell, or exhaust leak sound. acplus2008-11-15 17:53:43

Thanks John,

Suppose to be real nice here tomorrow. I will definitely go for a long ride.

Scott

alright Scott!!!!    Drive baby drive!!!

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