With the numerous gaskets, types, materials...what works best for as 60s cast Corvette valve covers. Recent cork materials have lost something... seems too stiff.
Ran old Corvette valve covers on my race cars. Glued cork gaskets onto the covers and lightly greased the side that touched the head. Never had a leak and I ran the valves once a week.
I always liked the cork/rubber thick gaskets Mr. gasket has/had because the head isn't machined on that surface rubber ones just didn't seal right. Straight up RTV? That's for sealing the corners of oil pans and intakes. These are about the same as the old Mr. Gasket. https://www.summitracing.com/parts/edl-7548
Haven’t done perimeter bolt valve covers in a while so I can’t comment on the New cork issue. But for years I also glued the cork gasket to the cover with weather stripping adhesive and a light coat of RTV on the head side of it wasn’t going to be removed. Grease is great if your routinely removing. Maybe try a different brand of gasket if your not happy with the flexibility.
I've been using the silicone gaskets with metal strip imbedded in the center. I install them dry and haven't had any more problems with leakage. On the SBC's, I found the cork gaskets tend to dry out and shrink over time from exhaust manifold/header heat and stop sealing so, switched to the silicone. They haven't given me any problems, even with being removed and re-installed several times. They're more expensive than cork but, do work very well and I feel they're worth the extra cost.
I’ve also used the silicone gaskets and as doublepumper said dry. First time I tried them I put RTV on them and they slid rite out. They also didn’t have the steel insert which is a must. This was 30 plus years ago and fairly new to the market.
I have been using cork on my Corvette aluminum valve covers for 60 years without any leaks.....no sealer, just snug them down.
Will give it another go. Put NOS Moroso cover on left side with cork.. bone dry. Corvette with cork rt side, leaks like a sieve. Will try another vette cover. Tomorrow is another day..
OP, this man has it right. I used same procedure with my SBC race motors, though I had the tall die cast Moroso covers for stud girdle clearance.
I use cork, and the thick style. I use black RTV gasket maker to stick them to the valve cover, but nothing on the head side. Just a thin coat, and then put bolts through the holes from the gasket side out while they dry. Once they're dry enough, just bolt them on and they never leak.
FelPro cork. Aviation gasket maker (very thin coat) on the cover side to stick them on. I light wipe of grease on the head side. They neither leak, nor stick to the head on removal.
Put sealant on top side of cork gaskets to valve cover. And light grease on head side. Looks like it might be working.
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