For old iron like the relics we work on, you really need to hone your tinsmith skills to form the sheet metal to fit the cast iron. The cast iron surfaces are usually very straight. Just make sure that they are squeaky clean. Oil pan, valve cover, and side cover can be checked for fit by bolting them on without gaskets. If they don't fit tight without gaps, good luck getting them to seal with any compound. Time to get out the body hammers and fine tune the sheet metal. Take a look at the areas where the bolts go. They get abused by over tightening and need to be hammered back out. 216 and early 235 valve covers tend to get bowed outward along the sides from over tightening the 2 acorn nuts. Mash them back in by hand.
Cork is your friend. Spread a layer of engine oil on them before you install the sheet metal. If you feel that you must tack the gasket to either the cast iron or the valve cover (not both!), make sure to put the oil on the surface which did not receive the compound.
Applied oil will soak into the cork, causing it to increase in thickness, resulting in a tight seal.
Do Not over tighten the screws! That is where most leaks come from.
Carl
Last edited by 52Carl; 11/05/2017 11:20 PM.
