Please excuse the simplicity of my question here. I am new to engine repair....I am in the middle of an intake manifold repair on my '86 305TPI and I am unsure as to which RTV would be the best to use on the block and around the water jackets. I bought ultra blue, but I have seen postings about guys using ultra black, black aircraft grade, or ultra grey or even something called ultra copper. Also, is permatex 2 the best thing to use as thread sealer on the manifold bolts? I've got one chance to do this right and don't wanna screw it up. Thanks!

 

ultra blue will work out great. I have used ultra blue, but lately have switched to ultra black, so that the blue doesn't stick out when I'm building 'show car' type stuff. they are very similar in characteristics, you could almost say they are the same just different colors.

never used permatex 2 for intake bolts, you could just as easily through a smudge of ultra blue on the threads and call it a day. really, only the middle 4 bolts really require any thread sealer, but i usually never see an issue with leakage.

good luck!

 

thanks for the help! With the wife and kids around hopefully I'll "git r done" before the first snowfal. Took me a day to tear it down and it will be 3 months putting it back together.

 

I like the grey Hylomar import gasket maker myself. That stuff works really well, but the ultra blue or black should work as well.

 

Blue, black, gray or even ultracopper is ok...


just as long as its permatex.

permatex makes some great stuff.. theres alot of other crap RTV out there.. i know there are other companys that make good sealers, but i know permatex works, and you can buy it everywhere cheap.

btw:

ultra copper is high heat: good for exhaust stuff, like EGR blockoff plates, ect..

ultra black is the most oil resistant: good for when you cant get somthing perfectly clean before you assmble it... also its hard to see since its black.

i dont recall off the top of my head what blue and gray are "better" at, but i like gray because it blends in with alum parts.. makes it look neater.

 

Blue is supposed to be the most coolant-resistant of the RTV's. Personally I use black on everything except exhaust, which I rarely feel the need to use RTV on anyway. I also like to just rub a little black RTV into the threads of the intake bolts instead of using a thread sealer.

 

Ultra Blue! For exhaust, use Dead Soft aluminum gaskets and you don't have to worry about sealer.

 

umm, just FYI.

when i said exhaust, im talking about when you need to seal a custom blockoff plate, like on LS1 cars.. or when you have a slip fit header tube and need it to seal.

you DONT use it on exhaust manifold gaskets or collector gaskets.