Exhaust Manifold Gaskets

[tahoe healey]

Once again (third time in 10+ years) I am getting an exhaust sound at the down pipes. The gaskets leak. I've been told that no sealant is used on these gaskets, but they keep failing.
My questions are:
Can I use some kind of sealant? Heat being a factor.
Is there an appropriate amount of torque?
Is there a better gasket than sold by Moss?
Which side goes toward the engine?

 

[BoyRacer]

Are you talking about leaks at the manifold flange where it meets the down pipes? If so, then use RTV high temp sealant on the gaskets. But if you are continuing to have leaks, I suspect the manifold flange studs are corroded enough so that the nuts won't hold tight.

 

[tahoe healey]

It is the flange that takes the triangular between the down pipes and the pipes to the exhaust system. The studs are good.

 

[Bob_Spidell]

I fought this bugbear for years. I went through several sets of brass nuts and studs--including stainless--and snapped a couple studs (one even with the flange). On one long road trip, before startup I'd get a ratchet, a deep socket, two long extensions and crawl under my car to torque the nuts. That got old in a hurry; my solution (concours types shield your eyes):

1) take the downpipes off and flat-file their flanges (if you ever have your manifold off flat-file its flanges as well)
2) get the best gaskets you can (most suspects are selling the same type at any give time). Copper/asbestos is best, at least get the copper if you can
3) coat the gaskets with a good high-temp RTV and coat the stud threads with high-temp anti-seize
4) offer up the flat, smooth flanges to the studs in the manifold
5) secure the downpipe flanges with grade 8 flat washers under first, one nut torqued down to about 20lb-ft, then a jamb nut on top; torque it as well (it will torque the first nut a bit more)

I've gone many years and miles without a leak.

 

[Dandare]

I was amazed many years ago when I saw a muffler shop using silicone in this application, it works well. I don't think they even used the special high temp stuff!

Danny

 

[LarryK]

I use the exhaust pipe, muffler caulk.