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

astreib, you come to the Forum with a difficult problem. Anyway, welcome to the Forum. There has been a lot of discussion on the "Diesel" forum concerning replacing the front pulley/balancer hub. I have never had to do it, hope I never have to stare that one down. If you use the search function close to the top of this page, just type in replace harmonic balancer, you will probably come up with more good reading then you will want for one night. There have been a number of instances where replacing it incorrectly have led to massive repair or scrapping of the whole engine, so study the problem good.

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

Here is a good page I just came up on "crank balancer"
http://www.peachparts.com/shopforum/search.php?searchid=5832543

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

It will matter when it comes time to check the IP timing.


No need to do anything with the chain sprocket. But I would certainly replace the crankshaft spacer and front seal.

Well of course that makes sense. I can set the motor at TDC and then fit the balancer so the 0 degree mark is in the proper place... duh.

I've read some of the other threads, and the engine manual, about how to install the seal and balancer. I do have a new bolt, new cupped washers, new seal, new spacer, and new pins.

I did not see anything specifically addressing the footnote in the manual about static balancing.

Allan