1990 318is/M42 exhaust manifold

[mark_i]

hi guys, joined the e30zone last week, all good.

looks like exhaust manifolds and removal has got a good coverage recently... my question is: how to check if a 1990 M42 manifold is crack-free?
engine makes all the right moves, but is noisy up to 3500 rpm, then quieter when the fun starts and all the way to the red zone.
Also a faint fuel smell from the engine bay when starting from cold.

[mark_i]

i know the Oz time zone and seasons are outta synch, but a reply would be good...

[Chris-W]

If your manifold is cracked, chances are it will be on number one, and you would be able to see carbon deposits between the mounting flange and the pipe itself, as if someone had held a candfle on it.

[Gwynleym10]

just have a look inside the at the cyclinder head end, should be able to see a crack in the weld if there is one.

If the engine is loud at 3500-4000rpm then is probably the timing chain tensioner, or even the timing chain itself.

Check all the fuel pipes when engine is running for fuel.

[stuartgallafant]

the petrol smell is the 2 2inch pipes that are underneath the inlet manifold. they go brittle and crack

[Chris-W]

2 inch pipes???

[stuartgallafant]

yeah, the fuel delivery/fuel return pipes run from the bulk head, where they are metal, then turn to rubber for about 5-6inches long, then they're metal again until it disappears under the manifold, the theres two 2inch rubber pipes that go from the metal pipes to the actual fuel rail

[Chris-W]

Ah, two inches long. Sorry. Thought that sounded a little sewer like

[mark_i]

Ah, two inches long. Sorry. Thought that sounded a little sewer like

Thank Chris and Stu, an interesting combination of pipework to check-out today, Cheers Mark

[stuartgallafant]

no worries

[mark_i]

Visually, the manifold and fuel lines look intact, the latter are still remarkably pliable.
The noise must be what gwynlem suggested... timing chain or tensioner. If it is the chain, a dude at work reckoned the cranknut needs to come off with the starter motor slamming a breaker bar into a wood block mounted on the the chassis? For real or a wind up?

[stuartgallafant]

thats the way i got mine off

[mark_i]

Thanks again Stu, I'll start a new thread when I've got the bottle (and a big enough block of wood) to give that a go, I'm in shock.