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I purchased some script, 7-fin valve covers for my 327 that is currently being gone through. I want to make sure that I have a good seal between the heads and the covers. I plan to have these vapor honed soon and was looking at the seal surface and noticed that the valve covers are not all that flat - with raised 'injection' points and other casting flaws. My question - should I clean these up before or after I get them vapor honed? Also, what is the best way to go about cleaning off burrs and raised points without compromising the areas that are nice and flat?
Be sure the valve cover gasket area is surgically clean. Apply a thin bead of Permatex Ultra Copper around the entire edge. Buy some FelPro #1604 Cork/Steel laminated valve cover gaskets. Set the gasket on the Permatex edge. Lay the valve cover (gasket side down) on a flat surface with some heavy books on top of it for 24 hours. Done correctly, you will have no leaks. Oil leaks, at the valve cover, typically occur between the valve cover and the gasket NOT at the gasket and head.
Great advise above. Make sure you have the correct length bolts. Otherwise, too long and they bottom out, yet you will think all is right before leaks start. Dennis
I have 4 engines with Corvette alum finned valve covers.. I use the thick, good Felpro gaskets with Permatex on the valve cover side of the gasket and very carefully position the gasket on the cover and secure them with several small spring clamps for a few hours. Then carefully place them on the head and evenly tighten the bolts. No leaks. Two engines have been together 20+yrs with essentially zero leaks.
One engine has staggered bolt pattern covers on heads with a straight across bolt pattern.
Slightly irrelevant to the OP's question, but those round "flaws" are actually ejector pin locations used in manufacturing. After the pattern cavity has been filled, pins in those locations push the valve cover off the mold.
Be sure the valve cover gasket area is surgically clean. Apply a thin bead of Permatex Ultra Copper around the entire edge. Buy some FelPro #1604 Cork/Steel laminated valve cover gaskets. Set the gasket on the Permatex edge. Lay the valve cover (gasket side down) on a flat surface with some heavy books on top of it for 24 hours. Done correctly, you will have no leaks. Oil leaks, at the valve cover, typically occur between the valve cover and the gasket NOT at the gasket and head.
I recently had to replace a cracked valve cover - and followed this procedure to a "T" (other than substituting Permatex Ultra Black). Worked like a charm! As Leif says, the keys are to bond the gasket firmly to the cover and to use a steel laminated gasket in order for it to maintain it's form. I used the Fel-Pro item, but I did run a cross an alternate with similar construction for quite bit less on eBay that might be acceptable. The cork only gasket I removed was a nasty azzed thing when I pulled it out. Little doubt, there was a leak, someone overtorqued the fasteners and thus cracked the cover at one of the mounting bosses, which just made things even worse. Sometimes...there IS a substitute for torque! ;-)
Last edited by JohnnyRay; Feb 27, 2024 at 06:48 PM.
Plain cork gaskets have worked for 1000 years.. When they were putting these valve covers on horses.. Some of youse guys overthink this stuff.
And they have worked like crap for 1000 years. I'll stick with Leif's recommendation as a better solution. Do you think Fel-Pro came up with those gaskets just so they could charge a little extra?
with both of the above.....those 'raised' spots could be there to keep the gasket from rolling up
Script Valve Cover Question
Dennis
