Questions about balancer installation

[astreib]

Hi all,

Earlier this year I bought a '79 300SD with a "bad" crank balancer. It had come loose somehow, and actually broken the big center bolt. I have my theories on how this happened, but regardless...

I finally got the parts to repair this, and am ready to tackle the job and see if things are OK after that.

I consulted the engine service manual job 03-340 and several questions arose. First there is a footnote that states "when the balancing disc is renewed, static balancing is absolutely required."

The balancing discs are not currently available new, according to my supplier, who also indicated that there was no foreseeable availability on them. So he arranged for a used one, which I assume would have been balanced already correct? There are drilled-out areas on the perimiter that would imply this.

Do I need to worry about trying to do this "static balancing?"

The used balancing disk is from a 617.952 motor, while mine is a 617.950. Would this matter?

Secondly the manual states that when removing the balancing disk, mark its position by making punch marks on the disk and the crankshaft. Since the disk was already removed by the PO, and I'm not putting the same disk back anyway, does the original orientation really matter?

Third, my parts included a new woodruff key for the crankshaft gear, but reading the remove/install descriptions of for the balancer it does not say anything about removing the crankshaft gear. Can I just leave that alone?

Any thoughts on any of this?

Thanks!

Allan
--
1979 300SD
1983 300D