intake exhaust gasket - use silicone too?

[BadDog]

I've got my car apart, and am about to install my new header... but I can't find anywhere if I'm supposed to use hi-temp silicone in addition to the gasket or not... please advice :-)

[Ed]

I installed my header without any type of sealer. The gasket sealed good but after about 10k miles the "performance header gasket" developed small "cracks or pin holes" creating small leaks. I have seen people use some kind of copper based sealant that is for the high temps. When I replace my gasket I am planning to use this copper based sealant to see if it makes the gasket stronger.

[BadDog]

cool thanks :-)

[hmsports]

I've never used sealant on any of my header gaskets and I think I remember reading against it.

[ZmeFly]

something else you may want to do is also check your torque settings on your bolts

i found after a few days of driving the car they tend to work there way loose again.

[2ManyZs]

Proper torque! Make sure the header flange is flat! No burrs, welding slag! Two of the best pieces of advice when installing a header on a Z.

I've used two different kinds of gaskets without a sealant of any type with pretty good luck with both. One is the type that is foil covered, it's a paper type gasket, but it has a dimpled foil or metal covering. The best one to use is one that is foil covered with the metal seal made into the gasket.

I would only use a copper sealant if I used one at all, the heat will probably be too much for anything less.

[Ed]

Another thing to look at is the flange thickness of the header. On mine the intake manifold flange was thicker than the header and I had to modify the washers to get equal torque on both.

[Graeme Suckling]

Quality issues aside, on exhaust joints I use a product available in OZ called MANISEAL.

Comes in a flexible 145g tube.

This is an exhaust cement made by CRC and is also suitable for kiln repairs up to 300deg C.:classic:

[skip260z]

but I plan on putting a thin film of the copper antisieze paste on the gasket, both sides. Will use it on the studs and nuts too.

I use VersaChem Type 13, good for 2000 degF.

Use it on all my cars for plugs, SU carb screws; any place where I want to prevent 2 parts heat welding together or from dissimilar corrosion.

[BadDog]

Hey where were all you guys Saturday morning when I needed you? ROTFL

I ended up using a thin bead of silicone just around the intake ports on the head side (local shop suggested that). I got everything back together, fixed my high idle (check my other HELP!! thread), and quasi-hung the tailpipe. Sounds good, now I've just got to get it to a muffler shop to hang the tailpipe correctly