Engine: Best seal for new cork valve cover gaskets

[Dan Gosch]

I'm replacing my valve cover gaskets on my '55 Commander with new cork ones. Is High-temp silicone gasket maker a good seal to use? If not, what is? Should sealer be applied to both sides of the gaskets? Thanks.

[62 Lark]

I wouldn't use silicone with cork gaskets. I would use some Permatex High Tack to hold them in place, until you bolt them down.

[altair]

I was just fitting a neoprene gasket onto a valve cover, the gasket is slightly smaller than valve cover and it must be slightly screeched to fit. This allows the gasket to fit tight in side the valve cover. I can hold it upside down and it will not fall out it is very tight in there. My personal preference is no sealer, with two perfectly clean surfaces there should be no leaking. However if you have excessive crankcase pressure due to plugged breathers nothing will stop it from leaking. I haven't used cork therefore I do not know how tight they fit, if they do fall out I would only use about four dots of rubber cement to hole them in place. Opinions may vary. The ultimate goal is to keep the oil inside. I have assembled at least a dozen engines and I have never used any additional sealer any where and have not experienced any leaking. A clean surface is most important.

[Hawk GT SS]

With an old school cork gasket I use an old school gasket sealer. As another option you could try is using some Gasgacinch, it's similar to Permatex high tack (also good). As they used to say; its the gasket that seals not the sealer. Gasgacinch will hold the gasket in place while you put your parts together. Better yet, it will allow you to easily remove the old valve cover gaskets from the valve covers next time you change them. You can apply it to both sides if you like but it's not usually needed. Most people do and it won't hurt anything plus clean up is super easy. Made in USA . Just don't over tighten the valve cover nuts. Things should work out fine. Good luck!

[ColoradoHawk]

I would also recommend placing your covers on a known flat surface to verify they are flat as well.
My valve covers at one time always seemed to leak no matter what I did. Then I checked them for flatness and found my problem. Now, no more leaks.

[Mike Van Veghten]

I use (have for MANY...years), use silicone to bond the gasket to the rocker cover. Then set the covers on a flat surface with some sort of weight on them, on a flat surface for a couple of hours for the silicone to set.
Then use a little grease (whatever I have at hand) to the cylinder head side of the gasket, and install them.

The grease helps seal them to the head, AND also makes removing them for the next rocker adjustment a snap !

As long as the gasket sits "flat" in the groove in the rocker cover...no leaks.

Mike

[DEEPNHOCK]

I agree with Mike......
I use Permaex Ultra Black on valve cover gaskets. Set them on a flat surface with a weight on the valve cover....overnight.

I use (have for MANY...years), use silicone to bond the gasket to the rocker cover. Then set the covers on a flat surface with some sort of weight on them, on a flat surface for a couple of hours for the silicone to set.
Then use a little grease (whatever I have at hand) to the cylinder head side of the gasket, and install them.

The grease helps seal them to the head, AND also makes removing them for the next rocker adjustment a snap !

As long as the gasket sits "flat" in the groove in the rocker cover...no leaks.

Mike

[Hawk GT SS]

Sounds like Dan has a lot of good options to choose from here. I do use the Permatex Optimum Max Flex (similar to Ultra Black) when using Neoprene gaskets on the flat surfaced Aluminum valve covers and weigh them down as suggested in the above posts. It works. I only use it on the valve cover side however as I check my valves regularly and want to be able to get the covers on and off without a fight. I use Gasgacinch on the head side of the neoprene gasket to help with those minor imperfections while still retaining the ease of removal. It's been about a year since I did this with no leaks yet on my weekly driver. While I'm sure that Permatex black would work well on cork gaskets too, clean up and change out on the stock valve covers seems like it would be a real pain and a lot of extra work. Just my 2 cents and something to consider. Take care and have fun.