Header gasket orientation

[-Nemesis-]

I just rebuilt part of my exhaust to try quell an annoying exhaust leak from the bodgey header flange. After re-installing I now have a really high pitched metallic clicking/ticking as opposed to the normal raspy tick of an exhaust leak. Only does it under load, so I assume it's exhaust. It's loud enough to hear clearly over a 3" exhaust.

Anyways it's too dark now to do anything, but i'm wondering about the manifold gaskets, the original MLS ones. I noticed there's a definite pattern on the surface of them, on one side the gasket ring (per exhaust port) is concave, on the other it's convex.

Is there a particular side that's meant to face out? Or does it not matter?

Also, with such a high pitch loud sound, I assume it's header gasket, agreed? My welds were over the top, I doubt it's one of them. In fact i'm not convinced I did the header up tight enough even...

 

[Zuffen]

Bryan,

According to the Toyota workshop manual the white paint goes toward the manifolds.

I know the white paint was probably burnt off years ago! The paint is located on the "joining" bridges between each port.

Unfortunately they don't mention the convex/concave bit but I would lean toward the convex side being toward the manifold. Don't ask why it's just the way I would do it.

 

[stevechumo]

I had the same confusion as you do now. I use aftermarket MLS gaskets. I don't remember which color faces in, however, I found out left and right can't be interchangeable. My memory isn't too good, although I just replaced the gaskets a little more than a month ago.

On each gasket's last and first runner, I believe there're 2 tiny notches about 1mm (could be 1) that will clear out of the headers and the heads. If you put left to right and vice versa, the header will press on those notches against the heads and the exhaust will leak because of the openings there. If you can take a close picture of the gaskets with the headers on, then I can tell you.