Possible exhaust leak in engine bay

[ewolfe57]

I've finally got my headswapped Eta running after a few weeks slowly ironing out the kinks, but I'm still getting some issues. The one that currently concerns me is fine smoke in the engine bay. It definitely seems to be the same that's coming out of the exhaust so my thought is an exhaust leak out of either the head to manifold or manifold to downpipe gasket areas.

I'm fairly confident of the head-to-manifold connection, but not so much on the manifold to downpipe. The gasket kit I got came with two different gaskets for that seal; one is just a thick metal plate, the other a more typical thick gasket. I just used the normal looking/feeling gasket, is it possible I did this wrong? What's the best way to check? As far as I can tell it doesn't smell like coolant is burning.

Related, how difficult would it be to replace the gaskets without removing the manifold from the head if I dropped the exhaust? How many places is it held up?

[Seawolf]

If you want to drop the complete exhaust you'll need to open up the rear muffler hangers and separate the cat back from the front pipe. The front pipe is supported by a bracket just before the cat and the manifold connections.

When you reinstall the downpipe loosely support the cat on the hanger and a jack stand, apply a thin coat of AcoustiSeal 35959 to the downpipe gaskets and bolt up loosely. Position the downpipe so that it is not stressed and tighten the rigid downpipe first, then the flexible downpipe.

Fit the catback and hang loosely with the rear muffler hangers using new sealing rings & AcoustiSeal for the connections. Again position so the exhaust isn't stressed in position or touches/bangs on anything then work round the joints and hangers pulling everything down tight - do this gradually to avoid setting up stresses in the exhaust system.

Done.

[e30onBBSs]

smoke test

[efficient]

Maybe your flex pipe by the o2 sensor is cracked and leaking