Who uses silicone
 

Do you guys like to use silicone on your cork oil pan and valve cover gaskets or not

I just got through trying the neoprene and then cork without anything. Cork did better but still leaked on the back side near the firewall. Plan to use some sort of non-hardening sealer of some sort.
And yes - I verified that my valve covers were straight and not bent from over tightening..aftermarket which is likely the issue.

I use high temp RTV... a very, very, very thin bead to act as a gasket glue and to seal up the small imperfections of the mating surfaces.

If it oozes out, that means ya used too much.

blue glue
 

top and bottom?

Not blue, I use black or that high-temp dark red.

Yes, top and bottom after letting out-gas for about 10 minutes before mating the surfaces. Works like a charm.

I use a cork gasket with gasgacinch or Indian head gasket schelak. I also only torque the valve covers to 20 INCH POUNDS in a cris cross pattern. Let it sit over night re torque. Then I drive the truck and re torque. I have had no leaks in the valve covers following this method. Just make sure your flanges or as flat as possible or by new ones.

Silicon and cork is a tricky combo. Silicone acts a a lubricant and also can soften cork when wet. It may cause gasket tears if the joint is torqued with wet sealer. The gasket basically squeezes out. If used with cork, use sparingly and tighten the joint finger tight. After the silicon has set up, a couple of hours, tighten completely. I generally prefer other adhesives or sealers - like spray trim adhesive or high tack - with cork or use it dry.

I was taught that silicone has no place on an engine. Ive only ever used gasket glue and proper torque specs. Ive built several engines and ive never had leak issues. I use silicone for diff covers and stuff that cant be damaged by chunks of silicone floating about