I'm looking for a temperature rating for silicon used when putting cases back together. Copper is 700, red 650, black 500. I believe their ratings

I'm coating my cases so I prefer a black or clear.

But what temperature rating I need and brand recommendations?

 

Most I know use Yamabond

 

The regular black stuff works fine, no need for high temp.

 

i agree,the black works fine,put on very thin coat.DONT use yamabond

 

No need for high temp. Three Bond 1211 or 1215 have worked for me and specs say 250*C. Like Kirby says, very thin coat is all that is required. It is gray in color but any that is squeezed out can be trimmed. The consistency makes is easier to apply a very narrow bead. Videos on the net illustrating proper application are available.

 

just buy the factory stuff, it is a floromastic base and not silicone. the dealers sell it and if not, a gm dealership.

 

Ok, seriously now, what's wrong with Yamabond?

 

I went to O'Reilly and got a tube of Permatex Motoseal 1 Gasket maker and it worked great. I have just 3000 miles on this build without a problem.

 

don't like it,wont use it.makes things way too hard to get back apart,maybe on panhead on knuckle stuff were the fit of parts isn't that great,but defanatly not needed on more modern motors