I checked the archives but didn't find anything. Gaskets on my 69 427/390 are seeping oil. Tightened down (just a little more than snugged) and it helped but didn't stop. Gaskets are cork, don't know how old. Should new gaskets stop seeping or do I need to use a sealer too?
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Re: Leaky Valve covers
Bob,
Well, there is something there in the Archives but I don't remember what title it might be under. I asked when I had the same problem and had already gone through two new gaskets. I had been tightening the valve cover bolts too tight and smashing the cork. Try a new gasket and don't tighten the bolts too tight. The other thing is to make sure the edge of the valve cover is as straight and level as it can be. TBarr #24014 -
Re: Leaky Valve covers
It also helps to use a bead of RTV sealant between the gasket and the valve cover, so the gasket is both sealed and adhered to the cover. This keeps the gasket in one piece and makes it easy to remove the covers. Oil runs down the inside of the covers, and the first thing it hits is the top surface of the gasket, and tends to leak out between the top of the gasket and the cover - the RTV will stop this. If you look at late Chevy small-block center-bolt valve covers, you'll see that they're shaped such that the oil runoff from the inside of the covers drips off well inboard of the gasket, and in fact never even touches the gasket - that's how they dried up the OEM design.
JohnComment
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Re: Leaky Valve covers
Geezer here. -- You might also try a set of Corvair valve cover springs to spread out the load. I often used these in the old days. Available from Warshawsky (that's J. C. Whitney to you non-Chicagoans), if not fromyour local Chevie store. I know, I know -- They are not stock -- But they SHOULD be !!Comment
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Re: Leaky Valve covers
Geezer: Corwhat, valve cover springs from a WHAT are you gonna put on your Corvette?
jerryComment
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Re: Leaky Valve covers
Jerry -- Yup, you heard me right. Corvair -- CORVAIR. Chevie had a method for spring-loading those horizontal valve covers so that the vertical gaskets didn't leak. J. C. Whitney even has them in chrome -- look on page 190 of their latest catalog, center column, bottom of the page. They are pictured upside-down. Believe me, those suckers really help to seal the valve-cover gaskets.
BTW, toward the end of its life, that l'il Corvair, with its engine-over-drivetrain, was relatively awesome. It could always beat out the Corvettes at the mid-winter ice-slaloms, even if the Corvette had studded snow tires. The six-cylinder spyder, with (I believe) a turbo, could really perform.Comment
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Re: Leaky Valve covers
the same thing is avalable from moroso so your local speed shop can supply themComment
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Re: Leaky Valve covers
Bob---
The best gaskets that I have ever found for sealing perimter-bolt style valve covers are Fel Pro Cork-Lam gaskets with steel insert. These gaskets are 5/16" thick(a little thicker than stock)and are constructed of a cork-rubber compound. They are expensive at about $30 per set, but they work well. For Mark IV big blocks the Fel Pro number is 1630; for small blocks its 1604.In Appreciation of John HinckleyComment
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Re: Leaky Valve covers
For what is worth, the method I use with success is to use 3M's weatherstrip addhesive to affix the gasket to the valvecover, let cure, then using a RTV silicone, apply just a skim coat to the gasket face,not very thick,also make sure the head surface is prepped(clean with brakeclean or laquer thinner),then install valve cover,and do not over tighten. This should provide a leak proof seal for you.Comment
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