When was that design introduced? Was it meant to deal with power steering, AC, and diesel vibrations?

-J

Looking at wikipedia the M110 engine was introduced in 1973

http://en.wikipedia.org/wiki/Mercedes-Benz_M110_engine

and the OM617 in 1974

http://en.wikipedia.org/wiki/Mercedes-Benz_OM617_engine

So I guess 1973? Unless someone else knows better?

Answer
 

The most common issues are:

* The early W116 had some issues with bolt hardness.

* Incorrect removal procedure = Wrecking the balancer = failure to follow the FSM (Factory Service Manual).

* Re-use of pins = improper installation.

* Re-use of a damaged balancer = improper installation.

* Balancer installed 180° out of alignment = improper installation.

* Wrong bolt torque = improper installation.

* Using an oxygen acetylene torch on the bolt/harmonic balancer = improper installation.

* Replacing the three spring washers with flat washers = improper installation.

* Failure to re-install all three spring washers = improper installation.

* Re-using the cap screws that hold the pulley on = improper installation -
failure to follow the FSM (Factory Service Manual).

* Excess tension - of the accessory drive belts = tight enough to play like a string musical instrument.

* Lifting the engine by the balancer/pulley assembly = Failure to follow the FSM (Factory Service Manual).

if buying a used engine and not being sure about the above, how to deal with it?

what is the failure sequence of the above?

Thank you very much for the input.

So if you follow the procedure in the FSM everything should be OK then?

I was wondering about loctite as a precaution - just on the 27mm bolt.

Thoughts?




{I'll probably be shot one of these days for suggesting snake oil again!}

The only way you can see the condition of the parts is to remove them and check - unfortunately you then need to fit new pins... I'm guessing most people wouldn't check this though.

well i have a few used engines and no idea what may have been done to the balancers, but i'm guessing that if it was used to pull an engine, the failure mode might be that the balancer, in use, might then just break apart, rather that getting loose and spinning, but perhaps both are possible, after perhaps being weakened from the stresses of the engine pull , ..dunno

i guess it might be that if an engine was pulled by the balancer, the only sure fix is to use another good or new one?

Oh I forgot to say that I've started a thread in tech help to see if any petrol engine owners have come across problems with the balancer on their engines...

At the moment it seems strange that "only" diesels have this problem.

from the W210 wiki
http://en.wikipedia.org/wiki/Mercedes-Benz_W210#Reliability_issues

Thanks very much for the information - but I think the M112 and M113 engines use a different balancer system. According to this thread

http://www.peachparts.com/shopforum/mercedes-parts-reference-library/192083-000007008244-dowel-harmonic-balancer-large-engine-application-list.html

the pins that are part of the problem are not used in those engines

FYI
 

Crankshaft Balancer Failure! Must read.
http://www.peachparts.com/shopforum/tech-help/63512-crankshaft-balancer-failure-updated-post390894.html

I've had this issue happen to me three times in nearly two years in my 300D with the OM617a, once in September 2009, again in April 2011, and once again in June 2011. In the first instance, the head broke off of the 27mm bolt and left me without power steering, a/c, and the water pump. I immediately shut the car off before it could overheat. During the second incident, all I had was a horrible clacking and droning noise during acceleration, and the inspection once again revealed a broken bolt. The bolt was replaced and a new balancer was placed on the engine. During the last incident, I had horrible clatter, and the inspection showed that the bolt had backed out a little bit. All three times, the bolt was replaced with a brand new bolt and torqued to spec, and the FSM instructions were followed. According to the mechanic, he hadn't seen one car come in three times for that same problem, and he's been working on MBs for over 50 years. Here's hoping third time's the charm.

I am really afraid of the problem, wish to do all I can to avoid it.

I bought a parts car, an 82 300D that was finished for that reason.
It really messed up the front of that crankshaft.
And there is really no good way to check to see if you have a problem beginning. Anyway, I do wonder if the R-134A type freon is to blame for some of these incidents.

I was running my 85 300D on R-134A when it was cool, (didn't run it when hot because it didn't do any good), but it did seem to pull very hard, it took a lot of hp.

That is one of the reasons I was happy to eliminate A/C on my present 240D with the 617.
No A/C, and because of that I run the belt system with a lot less tension on the belts.

It makes for a delightful driver.
Indiana is hot, really hot in July and August, but I don't use the car much at that time, or I use the one car that has AC.

I suspect with running those belts with less tension I will greatly increase water pump and alternator life, and that is not to bad.

FYI
 

The type of refrigerant has NO relation to this issue.

There is NO connection between having or not having A/C.

If the higher head pressures from 134a caused slightly higher load on the silencer perhaps that would cause it to fail more readily? Though if that bit of extra load caused it to fail it was likely mostly broken in the first place.

-J