Exhaust sealant advice needed

[DougD]

Hello All

I recently took the headers and side pipes off my RepliCobra to have them ceramic coated. Now I am ready to put them back on, and I have a couple questions I'd like some advice on from the group. I have researched a ton of threads on the subject here on Club Cobra, but I'm still not clear on what I should use. Opinions seem to differ greatly, and most cars use a different arrangement than the headers/sidepipes that came with my car.

First, I have a pair of the high-dollar copper gaskets for the headers-to-cylinder head connection. Should I use anything on them, like hi temp silicone, use something else, or leave the gaskets bare?

Second, my headers use a slip fit for the eight individual pipes into the side pipes. Should I use something to seal the slip fit connection? If so, what would you recommend?

Thanks in advance, and I look forward to the group's opinions.

Doug

[Shootnride]

I personnally wouldn't use sealant on either of those connections. It's been my experience that the copper gaskets seal very well without sealant and the slip fit collector connections are also designed to work without sealants.

Just my 2 cents

Ted

[strictlypersonl]

A little of this on each side of the gasket will insure against leaks.
[ame="http://www.amazon.com/Permatex-81878-Maximum-Temperature-Silicone/dp/B0002UEOPA/ref=sr_1_1?ie=UTF8&qid=1411252774&sr=8-1&keywords=permatex+ultra+copper+rtv"]Amazon.com: Permatex 81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube: Automotive@@AMEPARAM@@http://ecx.images-amazon.com/images/I/51VTRuNBToL.@@AMEPARAM@@51VTRuNBToL[/ame]
Always re-torque the exhaust bolts after the first 100 miles and periodically afterwards.

[rodneym]

Doug,
Lots of folks are running graphite gaskets from Remflex. Sort of a last resort type product that seems to work, even on FEs
As far as the slip fit pipes, I'd leave 'em alone. Nothin like seeing some carbon buildup in those pesky unsealed areas of the fit Especially on white painted pipes.
But that's me

[DanEC]

This is what ERA recommends on their slip joint collectors. Surprised Bob didn't mention it.

[ame="http://www.amazon.com/Walker-35959-Hardware-Sealing-Compound/dp/B000CQDL94"]Amazon.com: Walker 35959 Hardware Sealing Compound: Automotive@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41W2dSVXfvL.@@AMEPARAM@@41W2dSVXfvL[/ame]

I have one joint that leaks a little on my motor until the engine warms up, where I failed to apply enough of it.

[ERA Chas]

No sealants in either place. Do a little work and use a pipe expander to get the slip fit connections better.
The copper gaskets are fine or the Remflex.Get 1" long header bolts, not the standard 3/4" and use antiseize on the bolt threads into aluminum heads.

[Mastiff107]

Had copper, went to Remflex. Don't have to re-torque and thick enough so no chance for a leak.

[DougD]

Thanks for the feedback, Guys.

I had a small tick, tick, tick sounding leak before I took the pipes off for ceramic coating. I have "adjusted" them a bit with a pipe expander. And the header gaskets were crap, which I have remedied with the nice copper ones.

These headers/sidepipes are like a jigsaw puzzle to assemble. I'd like to get this right this time.

So to ensure there's zero chance of any leaks, I think I'm going to attack this in classic overkill style. Ultra Copper on both sides of the gasket, and Walker pipe sealant for the slip fit connections. I'll probably never be able to get them apart again. But if they seal up tight, who cares?

[rodneym]

Originally Posted by DougD

... I'll probably never be able to get them apart again. But if they seal up tight, who cares?

Famous last words.

Good Luck!

[DanEC]

Actually Walker's exhaust sealer advertises that it eases dissassembly. I've had mine apart with no problem but I didn't really have any miles or time on the original make up to fully test this claim. The old sealer does clean out with about any solvent that's handy. I've found a little shot of WD40 or other penetrating oil in the slip joints helps dissassembly.

[ERA Chas]

Originally Posted by DougD

So to ensure there's zero chance of any leaks, I think I'm going to attack this in classic overkill style. Ultra Copper on both sides of the gasket, and Walker pipe sealant for the slip fit connections. I'll probably never be able to get them apart again. But if they seal up tight, who cares?

YOU will care if you have to pull the heads or block.
Ultra Copper will burn out after a while and they'll leak again. GET THE 1" BOLTS. How do I know this?
Get the slip fit as close as you can. Then live with the result.
It's not a Corvette.