I am looking for a good quality gasket to work with my repro aluminum valve covers and chrome oil fill cap, both sold by Cars, Inc. The gasket that came with the cap was too thin to seal properly, even after bending the tabs a little. I found a universal chrome oil cap that has a thicker gasket, 1/8 inch, that works well but after 2 years gets soft and must be replaced. I am tired of spending 10 bucks every two years for a new universal cap and then using only the gasket. I've tossed at least 3 unused caps so far. Does anyone know where I can get a silicone gasket 1/8" thick, or gasket material to make my own?
https://www.gasketing.net/silicone.php Gasket material sheets are readily available. Just do a Google search. https://www.amazon.com/Fel-Pro-3060-Gasket-Material/dp/B000CNKUGO https://www.henniggasket.com/gasket-material https://www.autozone.com/sealants-glues-adhesives-and-tape/gasket-material
I ordered a couple different gaskets made from a silicone material today and will post results when I get to try them out.
i always use valve spring shims or similar shims with the gasket to keep cap tight against valve cover.