Sprockets TOO Worn (or Not?).... and should I worry.

[Nomadic]

My recently acquired E30 M42 has 196K and I am getting an occasional but definite chain rattle/slap @ around 3000rpm. (Don't know how I missed that on the test ride. )

My Sprockets [Photo Link] certainly look worn, but are they TOO Worn? The intake cam sprocket looks more worn to my eye. In addition she appears to be leaking a fair amount of oil out the front crank seal.

I've have a new tensioner in hand but I'm hesitant to pop a new tensioner into a worn system especially with the "Rev to Pop Tensioner" procedure.

Any Comments on the relative wisdom of the following plans?

A) Replace Everything - Sprockets(3) chain and guides, seal, gaskets water pump. (~$550.00 parts)
B) Replace Everything except for Sprockets. (~$430 parts)
C) Replace Rails, seal and water-pump, gaskets but leave chain and sprocket as is. (simpler procedure? )
D) Pop a new tensioner in, hold my breath and see what happens.

Any knowledgeable advice on this would be appreciated. [LowerPan comes off for UpperPan bolt check tonight...]

Thanks!

[BBY1104]

D)


go from there

I wouldnt buy 550.00 in parts i didnt need. I have heard of some m42 having 260-310k and the sprockets wernt worn just the tensior was worn out

[Majikal]

def. pop that tensioner in there. My chain was slapping HARDCORE when I bought the car. Popped a new tensioner in and problem solved.

[Jak]

Those are worn but its up to you. If you plan to keep it I would replace them. There is no point in doing it half assed. Putting in a few parts and leaving the rest is going to wear them prematurely. Of course you could just run it into the ground then put in a used engine for roughly the same price as the timing rebuild.

[kowalski]

fyi there is actually 4 sprockets, and you've got a little life left in those still. but definitely put a tensioner in. you really gotta start worrying when the sprockets get pointy.

[Nomadic]

OK, I'll go the with just the tensioner for the moment.... and wait and see what else needs sorting out on her. Right now I'm dealing with a stuck lower oilpan... I'll toss the tensioner in one I'm sure the oil intake is "bolt-free".

Thanks for ya'lls input!

[Nomadic]

Good News and Bad News, how bad I'm not sure.

When I got the lower pan off (heat gun and deadblow hammer ThanX ) I didn't find any bolts or shavings, but I did find a ~1 in bit of black plastic that was (looked like it had been) wrapped around bolt.

I'm guessing the plastic is from a Guide Rail or Tensioner Rail mounting bolt from what I've read here.

Any thoughts on broken bits of Rail? (196k)

Thanks!

[Jak]

Sounds like it could be from the lower guide rail.

Does it look like it could be a part of this?

[Nomadic]

Yup, It sure does.... the plastic bit measures 7/8in long which looks like it came from the right side of your pic. To be clear it was just a 1/4 moon bit of plastic... no metal/ no bolt. I thought that the lower rail was one of the tougher rails.... I imagine it would take some hard slaps to tag that rail.... but I'm new to e30s/ m42s.

[Nomadic]

Hey, Is e36 M42 timing gear a direct swap for e30 M42 timing gear? (rails & sprockets) I think the m44s have differnt cam sprockets.. but I'm not sure about e36 m42's.

Do you think it'd be worth looking for good used timing gear on bimmer forums?

Cheers!

[Jak]

Hey, Is e36 M42 timing gear a direct swap for e30 M42 timing gear? (rails & sprockets) I think the m44s have differnt cam sprockets.. but I'm not sure about e36 m42's.

Do you think it'd be worth looking for good used timing gear on bimmer forums?

Cheers!

Yes the cam timing gears and crank gears are a direct swap. The later M42s look like they have a rail instead of a deflection gear though. I have a deflection gear I would sell for $20 + shipping. Its used but in great shape.

At only $35 each for new cam sprockets I would say just buy new.