90 535i - Loud screeching noise (metal on metal) from engine 5 sec, then engine died

[mkinn]

Looking for advice before dismantling valve cover and checking engine timing marks.
I think it was a broken/loose timing chain tensioner, and now the engine is out of timing with bent valves.
What size is the crankshaft bolt? Any help appreciated.

[ross1]

Does it turn over?
T-chain failure on that engine is rare. T-chain failure will also stop the engine suddenly, no screeching.
Crank bolt is 32mm

[zubbie]

However tensioner will fail. How many miles?

[mkinn]

Unknown, 2nd engine. (1st one overheated) I just removed the valve cover, and the chain is off the sprocket, tensioner broken in pieces. The camshaft is at TDC, engine turns over with the starter, is it possible that no valves were bent? I'd like to try a new chain & tensioner before rebuilding the head.

[Binjammin]

Does it turn over?
T-chain failure on that engine is rare. T-chain failure will also stop the engine suddenly, no screeching.
Crank bolt is 32mm

Actually I think it's 24 or 27mm...

Unknown, 2nd engine. (1st one overheated) I just removed the valve cover, and the chain is off the sprocket, tensioner broken in pieces. The camshaft is at TDC, engine turns over with the starter, is it possible that no valves were bent? I'd like to try a new chain & tensioner before rebuilding the head.

Possible? Sure.

Likely? No.

[Layne]

I don't believe it's possible. On a 6 cylinder, I believe 3 valves must be open at any given time. I further believe that a collision is not avoidable in the M30, if the valve is open it's getting bent. So 2 bent valves minimum (maybe the 3rd one was only half open) but possibly many or all of them if the cam rotated at all during the failure.

[Binjammin]

I don't believe it's possible. On a 6 cylinder, I believe 3 valves must be open at any given time. I further believe that a collision is not avoidable in the M30, if the valve is open it's getting bent. So 2 bent valves minimum (maybe the 3rd one was only half open) but possibly many or all of them if the cam rotated at all during the failure.

By possible, I mean extraordinary odds against it, but as remote as that would be, it's still a possibility. Even a trillion to one is still a possibility.

[zubbie]

If no valves are bent you are the luckiest M30 owner ever to have lived

[Binjammin]

If no valves are bent you are the luckiest M30 owner ever to have lived

No m30 owner is lucky.

[m60b30530i]

No m30 owner is lucky.

I laughed hard this morning. I have 3 sitting in my garage. Retro fitting them to make custom boat anchors.

[zubbie]

I laughed hard this morning. I have 3 sitting in my garage. Retro fitting them to make custom boat anchors.

One of mine is going to be a coffee table. We should start a thread. "Best uses for an M30"

[thatonedood]

If no valves are bent you are the luckiest M30 owner ever to have lived

No m30 owner is lucky.

"Best uses for an M30"

#216: To drive green on tan e34s in to landfills

[ross1]

[QUOTE=Binjammin;27693099]Actually I think it's 24 or 27mm...



QUOTE]

Now that you have me thinking about it I think 32mm is wrong but I think it's bigger, 36mm.
No M30 here to confirm. (yes, I said that)

[zubbie]

Now that you have me thinking about it I think 32mm is wrong but I think it's bigger, 36mm.
No M30 here to confirm. (yes, I said that)

It's 36. Had to buy a axle socket set to turn the engine while setting valves

[Binjammin]

#216: To drive green on tan e34s in to landfills

[Layne]

I never saw a green on tan 535i... I don't think that came around until 1994. At least it wasn't common. So you'd have to swap the M30's into 94-95 cars before driving them into landfills.

[thatonedood]

Like a public service.

[Binjammin]

I never saw a green on tan 535i... I don't think that came around until 1994. At least it wasn't common. So you'd have to swap the M30's into 94-95 cars before driving them into landfills.

I owned one. 1992 and manual gearbox as well. It was the epitome of garbage.