The Stovebolt Site Forums The Shop Area Engine Shop Exhaust pipe to manifold connection

Putting my truck back together (slowly but not by choice) and today I was connecting the exhaust pipe to the manifold. My question is do you need a donut seal or a flat gasket for this connection? My exhaust pipe fits inside the manifold about half an inch and the flat gasket allows the exhaust pipe to fit firmly against the manifold. A few folks have told me I needed a donut seal but that makes the exhaust pipe stand off from the manifold by at least a half inch. The flat gasket seems to work better but I thought I should ask since I cannot find anything in the manual other than a system description..

Thanks
Deegs

If your manifold has a chamfered depression where the exhaust pipe fits, then you probably need a donut seal. My exhaust pipe is flared to fit a donut seal that's tapered on both sides.

But if the manifold is flat at the connection, then a flat gasket would be correct. Link

Thanks Kevin. I will check to see what type of manifold I have.

Deegs

I have not worked on an inline six, didn't some of them have the beveled manifold and a ball flare on the pipe? in which case you would need no gasket or donut.

That ball and bevel was not used on any Chevy six I've ever seen. Either a donut, or a flat gasket, depending on the year of manufacture, IIRC.
Jerry

Thanks Jerry, being I'm a young whipper-snapper without the wide range experience, I didn't know if that style was used. Probably 98% of my vehicles and experience has been GM V8's

I seem to remember the pivoting ball being used along with a spring-loaded flange to allow the pipe(s) to pivot a little as the engine rocks on a somewhat soft motor mount. It's seen pretty often on transverse-mounted engines that rock back and forth from torque reaction during acceleration. Older designs tried to keep the connection between the engine and the pipes more rigid.
Jerry