Knocking when engine turned off...

[Dave M]

I've done quite a bit of work on the car over the winter and finally pulled it out of its den for a peek at the sun. After running it to bleed the cooling system, I shut it off and heard a rather loud (louder than ticking valves)knocking from the back end of the M50 as it wound down and came to a stop. I repeated this a few times to determine the origin, but couldn't pin it down. My fear stems from a botched head cover gasket job performed by an indy. As the photo below shows, they failed to seat the gasket properly.
I'm no engine expert, so I have to ask,..... could the noise possibly be from a cam bearing not getting oil due to gaping hole where the seal is poking out? I know this may be a stretch and the noise is likely something else, but it would be peace of mind and/or an argument to the indy that their botch has damaged something else. Also, could it be the throw out bearing? I've heard it on occasion, but it was much quieter than this and while the car was idling with the clutch engaged.

The main things completed on the car this winter were;

re-built the shift linkage, guibo
replaced the exhaust (cat-back)
shocks/struts/springs all around


I know I'm asking a lot, but any input would be much appreciated.

Dave M

[ryan roopnarine]

all of the manual cars were supposed to make noises as the dual mass flywheels came to a stop..i don't know if that applies to the less torque-y m50 or not.

[Dave M]

Haven't heard this particular noise before, I'm dreading a crankshaft bearing, but strange that I hear it only after 3 months of sitting and fresh fluids all around.
BTW, I got the second package, thanks again.

Dave M

[winfred]

ether a worn out twin mass flywheel or much less likely a bearing in the tranny, id almost put money on the flywheel being bad, twim mass sucks, it will do it at idle on a m30 and sound kinda like a diesel idleing

[Dave M]

Thanks Winfred. Yeah, it sorta knocks like a deisel for a second just before it stops turning. If this is the case, am I able to drive it a bit without destroying things or should this be a priority and fixed ASAP.

[Dave M]

and there seems to be some debate as to whether the knocking is a result of the throw out bearing associated with such flywheels, or the flywheel itself. I have experienced the quieter knocking during idle with the clutch engaged, but not the knock while turning the engine off (much louder). Not that I'd attempt to replace just the bearing, I guess i'd just like to know whats going on in there.
Oh yeah, would like to know how long (if at all) I will be able to push the situation before replacing. So far, no ill-effects in the driveability and clutch departments.
Thanks again,
DAve M

[winfred]

it's more annoying then anything else, what's hapining is they stopped putting the take up springs in the clutch disc and put em in the flywheel, by time the 2nd clutch job comes around the flywheel is good and sloppy, i guess it could cause a problem if ignored long enough. i like to put early single mass flywheels on twin cars, ive never done a 525, on a twin cam 318 a m20 325i flywheel/clutch assy and a m20 starter because the teeth are different works good, it even frees up a little power, i can't remember the pitch of the m50s teeth

[TC535i]

Did I mention I LOVE my E28 clutch?!?!

[Crusty nz]

....get into.then it only does it when you forget or someone else drives your car.mines been like it for a couple of years now,no worries..

[Dave M]

Phew, couldn't see myself under that puppy for another weekend, ripping apart all I'd done. Much prefer to spend my time elsewhere. Thanks for the peace of mind all,

Dave M