Silver BB Cork Valve Cover Gaskets

[Wayne M.]

They're from a GM "Gasket Unit" package for cylinder head replacements, late 60s vintage, picked up at swap meets a decade ago. Finally decided to use them (found they'd shrunk a little over time). Questions are: were these ever used in factory installations ? My reading of the '65 Tech Manual says no. What was the purpose of the silver paint ?

Any suggestions for non-stick dressing on the contact surface of the cast iron cylinder head ?

[Mike M.]

Re: Silver BB Cork Valve Cover Gaskets

wayne; judges usually like the natural cork color. i too have several bb overhaul gasket sets from the 60's and they too have some sort of gray/silver coating on them. try removing with lacquer thinner and let us know if its removable. mike

[Joe L.]

Re: Silver BB Cork Valve Cover Gaskets

Wayne-----

I think that the "silver-colored" valve cover gaskets were used in PRODUCTION for big blocks. I can tell you, for certain, that both the 1966 Chevelle SS 396 with L-34 (360 hp) and 1968 Chevelle SS 396 with L-78 (375 hp) that I purchased new were originally fitted with the silver gaskets. I remember this well.

Both of those engines also had chrome valve covers and that MAY have been part of the reason for the silver gaskets, but that's just a guess. It may be that Corvettes also received the silver gaskets, but only for the 68-70 years when chrome valve covers were used.

[Clem Z.]

the silver material was a sealer

as my 65 396 that i picked up at the st louis factory had it and i found out how well it stuck the first time i tried to remove the covers. GM recommended that you used your hand to pound the cover sideways to break the bond but a large rubber hammer worked better. shrunk gaskets both paper and cork can be brought back by putting them in hot water but those ones with the silver "paint" may not because it would prevent the water from getting to the cork.

[Wayne M.]

Mike, Joe, Clem

So it looks like they might be a production gasket, as well as a GM replacement. Maybe I won't use them yet, as the car's just a driver for now. (got 2 sets that include steel head gaskets, rubber valve stem seals, intake -- one set has both oval AND square gaskets, black rubber manifold end seals with the little GM logo, exhaust doughnuts, etc.).

I tried lacquer thinner on a rag -- the silver does come partly off with vigorous rubbing. But it would seem not to be a lacquer-based coating.

So if they came on L78's, this would mean orange overspray, but showing silver underneath on the tabs.

I was thinking of running a VERY thin layer of silicon grease on the contact edge of the iron head, to ease in removal. Would this encourage leaks ? If the silver is a sealer, what kind of glue to use for the gasket-to-cover seal ? I was going to use GM weatherstrip glue (black, not yellow).