My trusty German mechanic is scratching his head cussing in German, and has decided to pull the engine to see why it wishes to keep loosing its flywheel. What to look for is the question,...as in any tell-tale signs of someting that may have been done or has happened internally.
Thought on this so far are:
1) crank not as straight as it ought to be.

2) Prior replacement of 2 pistons causing some kind of wacky behaviour/ocillation convincing the big bolt to remove its self.
* I thought it was #1 & #5 he thinks it
was #1 & #2 that was replaced.

3) some other unknown variable

4) black magic

I can deal with the first 3 I guess, that last one worries me a little.

Is everybody as stumped as I and my mechanic are?? Should we just rebuild the whole darn thing while its out?

-Larry :confused:


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03/83 300D
07/73 280

Larry,

Are you losing flywheel or crankshaft pulley/harmonic balancer?

------------------
Wilton Strickland
Goldsboro, NC
91 350 SDL. 81 300D

1) How many miles on this engine?

2) What was the reason for replacing two
pistons?

3) Were the replacements balanced? And
how?

4) What has been the engine's idle
and at speed characteristics since
the rebuild?

5) How many times since the rebuild has the
"flywheel" been "lost"?

6) Has the "big bolt" been recovered each
time a loss occurs? In what condition
are the threads on this bolt?

7) What condition are the crankshaft's
internal threads where the "big bolt" is
inserted?

Wilton, I am losing the crankshaftpulley/balancer combo.

-Larry

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03/83 300D
07/73 280

Larry,

Lost mine on 80 240D several years ago at about 67 kmi. Very upsetting!! Never knew why it happened. Some of the little bolts holding it came loose; others broke off!!
Good luck.

------------------
Wilton Strickland
Goldsboro, NC
91 350 SDL. 81 300D

Hello again, sorry I didn't reply to jgl1's queries right away, seems comcast was having a little fit late last night.

Anyway...

1. vehicle has ±184k on odometer.

2. I don't know the exact reson for replacing the first piston,...all I know about it, is that the compression was low.
The second piston (#1 I think) was replaced after everything was put back together, and a loud knocking was still present. The problem with this piston (as it was explained to me) was that it was loose within the cylinder...he said he could not tell that it was "loose" when he replaced the first piston. He said that some of the aluminum had to be honed off of the cyl. wall, but since aluminum is softer, the cyl. wall was unharmed by this procedure.
3. no balancing of any sort was done to my knowledge.
4. Idle characteristics...when at a light, it was a delight to look at my other half and see her body parts bouncing gently to the rythm of the engine. ;) I would suppose that if you took a yard stick and held it next to the car at idle, the car would move at least 1/2 - 3/4 of an inch. I figured that new mounts were in order. At anything above idle, the motor runs/ran very smooth.
5. This is the third time.
The first time the bolt was found broken in the fan shroud. about 1/2 an inch remained within the crank, it was extracted and replaced, along with the dampener and pulley (used parts). (they got eaten up a bit by the belts) The second time I got lucky...within moments of starting the car, the alt light came on/powersteering was dead...bolt was laying on ground. ( I was pounding the ground in dismay)
The third time I was on an exit ramp when the lights again came on, the steering went. this time the bolt is somewhere down in N. Ft. Myers on US 41. Reason I think this is so, is because I heard a series of clunks, that I first believed to be road debris that I had not seen. If the bolt indeed came out in N. Ft. Myers, then the whole kit-n-kaboodle hung on for another 70 miles before it gave up the ghost.
7. I did not see the threads too well (not exactly out in the open, they are) but from what I did see after the first time, the threads looked good. The bolts, even the broken one, looked to be unadulterated.

some story, huh?

-Larry (driving a...ah..an...an...lets just say its not a Benz, ok!?)

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03/83 300D 184k
07/73 280 160k

I have seen this before. I hate to say this, but the crankshaft is damaged. In some cases, the fit isn't as snug as it should be, and the harmonic balancer is prone to move. There are two little alignment dowels that go in there and will shear. Once this happens, they don't stay togther well because they are what holds the load. The bolt is jsut a retainer. I would be sure the proper amount of washers is being used and the torque is adhered to strickly if I was to let someone do this.
Good luck.

------------------
Benzmac:
Donnie Drummonds
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

[This message has been edited by Benzmac (edited 04-04-2000).]

small update...pulley and balancer removed...section of big bolt still in crankshaft. (guess I don't have to worry about looking for the bolt and its three washers...small consolation). Looks like its engine extraction time...what are your thoughts on cranks? Should I strictly go with a new one, or will a used crank in good condition be ok? Also, I am guessing that the turbo and non turbo cranks are not interchangeable...is this correct?
thanks for your time

-Larry (stuck with driving NOT a Benz) :(

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03/83 300D 184k
07/73 280 160k