Broken harmonic balancer

[koan]

my only concern is that I am not sure if the balancer and crank aren't balanced as a unit as other members mentioned, that would really complicate things.

From the jobs mentioned earlier the harmonic damper (confusing to call it balancer) can just be replaced. The balancer disc must be matched to the crank or it could be bolted on without needing balancing, have a look at the jobs.

koan

[Casey]

Good job catching it before something worse happened!

That would have been figuring it out when the belt started squealing.  There is no way I could possibly miss it the way it was horribly rattling around and generating sparks from the pulleys hitting each other.

What motor is in the 300D?

OM617.912 (non-turbo).

[Casey]

Incidentally, the MB book says to mark the pieces, I think the guy in the video has got it wrong.

Given that it was completely broken loose when I removed it, marking things (which I didn't do) wouldn't have done any good.

Shouldn't be that hard to take the valve cover off, rotate the engine to TDC, and know the correct alignment of the balancer based on the engine position, I should think (but am guessing).

[koan]

Shouldn't be that hard to take the valve cover off, rotate the engine to TDC, and know the correct alignment of the balancer based on the engine position, I should think (but am guessing).

Line up zero on the wheel with TDC #1 firing stroke would it, yes.

koan

[1980sdga]

Does the car have AC?

[Casey]

Does the car have AC?

Yes, why?

[Casey]

I'm wondering if I can't just replace the little dowel pins and keep my existing balancer...

[1980sdga]

Does the car have AC?

Yes, why?

There may be a correlation between balancer failure and AC.  The big center bolt does seem to come loose on the MB diesels. There are rumors of a recall for the problem.

Is this a concern for gas models?  I've had experience with balancers/dampers that use a woodruff key but never one with dowels.

[koan]

I'm wondering if I can't just replace the little dowel pins and keep my existing balancer...

I give up...

koan

[Casey]

I'm wondering if I can't just replace the little dowel pins and keep my existing balancer...

I give up...

koan

Why?  Do you know something I don't?  Why not just say what it is?  I said "I'm wondering", not "I think it's a mighty fine idea".  I don't know...I'm asking for input.

But it seems logical to me that if the big center bolt worked it's way out, and then the balancer came loose as a result, and that looseness caused the dowel pins to break...the rest of it might not be damaged at all.  I don't know.

[koan]

I give up...
koan

Sorry, I shouldn't have said that.

Just a touch frustrating that you finally arrive at a possible solution, a solution suggested many posts ago that received no acknowledgement at the time.

koan

[Casey]

Just a touch frustrating that you finally arrive at a possible solution, a solution suggested many posts ago that received no acknowledgement at the time.

Oh, sorry.  I must have totally missed that.

[1980sdga]

I just looked at my 1980SD and it is drilled around the edge. It depends on whether or not it was balanced as an assembly or "neutral balance".   I think it is irregularly shaped for a reason.

That's about 220 ft/lbs so so bolts must be goodentighten Koan!

[Casey]

That's about 220 ft/lbs so so bolts must be goodentighten Koan!

Yes, that's about the spec I read as well.  They are mighty tight - a real bear to get loose I'll tell you (got two spare bolts to prove it).

[1980sdga]

They are broken off.  I found them both inside the pulley, well chunks of them anyways.  The other chunks are still attached to the big piece.

Have a look at job 03-340 for your engine in the library, gives cross section and exploded view of relevant parts.

koan

I think it has been recommended that the cup washers (16) be replaced with new ones. Probably wouldn't hurt.