OK...part number for the 617.910/912 manual flywheel is:

617 030 00 05

Difference in length is 74.0mm vs. 90.0mm for the 300D, it's heavier but doesn't say by how much.
The SI is pretty explicit about balancing and not mixing them up and installing the wrong one, but in
this case I don't think it matters too much, since there is no "right" flywheel for the turbo anyhow.
The differences likely have everything to do with engine tuning, balance should still be OK.

MB list on this part has gone waaaay up to $515.00.

Quote:

The modified (for the manual conversion) driveshaft was made up from a remanuactured driveshaft (which to the point that the conversion was started, did not have any vibration) and the shortened front stub from a donor 240D. The work was done by a reputable shop and it was balanced after the fabrication was completed.

Hmmmm, totally grasping at straws here, but IIRC, the n/a and turbo driveshafts are not the same diameter.
If the "stub" end is from a 240, and the rear from a turbo, that could cause a vibration, I'd think moreso under
load. I could *definately* be mistaken on that though, it's been a while since I've looked at one, I just seem to
remember the turbo driveshafts being fatter. Maybe it's only the rear section (or all in my head). The
part numbers between say a 300D auto and 300D-T auto for both sections are not the same (I'm figuring those should be the same length, maybe they aren't), but I'm not sure how else they differ if not in diameter/weight, and aside from the different flex discs they ran between turbos and n/a cars.

langpfeife,
Thanks for doing the research on the 617 flywheel. It is good to know these things...

re: driveshafts.
Strangely enough, the old 240 driveshaft stub is bigger in diameter than the turbo's stub. Unfortunately, other folks that have done the conversion haven't really posted in here what shaft end they used for the conversion.

I'm curious, what symptoms would a worn centering sleeve exhibit?
How about failed bearings in the transmission?

Attached Thumbnails

 

__________________
Never a dull moment at Berry Hill Farm.

"what symptoms would a worn centering sleeve exhibit"
It causes people's rear view mirrors to VIBRATE....LOLOLOLOL

But seriously folks,

I suggested to Randy early on...that I suspected the flex discs.... but he is Almost as stubborn as I am... which he points out to me on a regular basis.....

The logic ? The amount of vibration actually reaching the rear view mirrors is so much that something must be moving pretty much to cause it to be able to be transfered that far....

The MB engineers experimented... and sometimes changed the recommendations for which type flex discs were supposed to be in their cars....

MB had what is called " tangentally " soft and " radially" soft flex discs.... which sometimes they would require one of each on a car...

I think since this is the only rubber thingy in the system... that either whatever vibration is trying to manifest itself is being caused by them OR that they are not in the configuration (or condition) to DAMPEN what is happening in the way the MB engineers put them in the system .

So, by saying they are EITHER causing the vibration, or failing to dampen what is there I am pretty much covering all my bases....
LOLOLOL

TCane had told me that the thickness of the two flywheels was different... so for those doing this it may affect the homemade tool MB describes for checking clutch disc wear.... just FYI..

ROFLMAO!

Or, it is in a frequency range that the motor mounts don't filter out but simply pass over to the body of the car.

Quote:

The MB engineers experimented... and sometimes changed the recommendations for which type flex discs were supposed to be in their cars.... I think since this is the only rubber thingy in the system... that either whatever vibration is trying to manifest itself is being caused by them OR that they are not in the configuration (or condition) to DAMPEN what is happening in the way the MB engineers put them in the system .

That's a valid point. And, there certainly are a LOT of flex disks and a lot of MBZ prose written on them as well. But, in this situation, which are the correct ones? FWIW, the disks in the car are about 1 year old.

And, in defense of my stubbornness, I'll remind all that the vibration is a much higher frequency (I'd guess 30-50Hz) than the rotating speed of the driveshaft.

Quote:

TCane had told me that the thickness of the two flywheels was different... so for those doing this it may affect the homemade tool MB describes for checking clutch disc wear.... just FYI..

The additional weight is most likely in the raised rim of the flywheel disk. If so, the part where the clutch assy. attaches would be unchanged as would be the go/no-go clutch tool.

__________________
Never a dull moment at Berry Hill Farm.

I may be onto something.

This morning, on the way to work, I realized that on the first part of my commute the vibration wasn't nearly as harsh as it was toward the end of the drive (8 miles w/lots of idling).

Could this be that the transmission fluid looses some viscosity after it warms up? Will the Redline solve this?

Ideas, opinions?

__________________
Never a dull moment at Berry Hill Farm.

"Difference in length is 74.0mm vs. 90.0mm for the 300D"--langpfeife

Mr. Langpfeife is nice enough to post the exact difference in length ( fore/aft )....
I say several times that one is thicker....
and yet you still are maintaining :

"The additional weight is most likely in the raised rim of the flywheel disk. If so, the part where the clutch assy. attaches would be unchanged as would be the go/no-go clutch tool."

This may be a closer race for most stubborn than you think....
---------------------------
"But, in this situation, which are the correct ones?"
It may be that your combo has not been determined yet ... ie, this will be a trial and error situation for a pioneer like you...
---------------------------

I don't know how accurate your butt is with regards to frequency vibration.... but have you considered making a chart which lists the rpm's of all the rotating items in your car ?
Then looking at which are moving at your 30-50hertz ( or mulitples of that in case of harmonic resonance ) ?

You say potato, and I say well, um, potato.
I think we're actually talking about the same thing. The clutch face area is bound to be the same on all models but the rim is thicker/longer/wider/deeper (pick any one).

This may be a closer race for most stubborn than you think....
It was never even a contest...ROFLMAO!!!
---------------------------
"But, in this situation, which are the correct ones?"
It may be that your combo has not been determined yet ... ie, this will be a trial and error situation for a pioneer like you...
And, the really smart, successful pioneers asked a lot of questions like: " How is the weather up on Donner Pass at this time of year?" and, "What are the symptoms of a failed output shaft bearing?"
---------------------------

I don't know how accurate your butt is with regards to frequency vibration.... but have you considered making a chart which lists the rpm's of all the rotating items in your car ?
Then looking at which are moving at your 30-50hertz ( or mulitples of that in case of harmonic resonance ) ?
A good idea; I'll look into this further.

__________________
Never a dull moment at Berry Hill Farm.

c'mon Greg, nothing on the viscosity question? You're getting soft in your old age.

__________________
Never a dull moment at Berry Hill Farm.

This measurement HAS to be the rim, front to back. If the center of the flywheel was that thick (90mm=3.54in) it would literally weigh hundreds of pounds.

__________________
Never a dull moment at Berry Hill Farm.

I am sticking with something outside the transmission because the tolerances on those shafts are so small that I don't think it could be moving that much and still function....
But the driveshaft is effectively suspended in RUBBER... and weighs much more than your 3 rd and 4th gears.... and thus has a much better chance of being able to produce this vibration...
So put the Redline in , feel better because it is great stuff to have in there, but don't be looking for that to cure this vibration problem....

Will do!

__________________
Never a dull moment at Berry Hill Farm.

He did not say what the total length was...
He said the DIFFERENCE was 16 mm
I don't know how thick they are.... or where this is being measured....
However, I am pretty sure your shop manual has that info somewhere.... If you would spend less time Golfing and Kayaking...

Gotta do something will all my spare time or I'll get into trouble.

__________________
Never a dull moment at Berry Hill Farm.

I see that there has been no conclusion to the vibration issue. Just wandering if there are any updates. I too took the plunge and put in a 4 speed into a 300TDT. Same problem as described by at least 3 people in this forum, mine has a slighly different rpm range but everything else is similar:

- balanced driveshaft (new u-joint too)
- 240d flywheel
- good rubber everywhere
- drives purfect 1st, 2nd
- drones/vibrates only under power between 2100-2500 RPM in 3rd or 4th


Any suggestions?

first, i dont think it is coming from the flywheel. the 300 and 240 flywheels are different in weight but both are for practical matters neutral balanced. the lighter weight will allow it all to vibrate a little more but it should not shake your mirrors.

the five has a bounce that is different from the 240 and will show up as a kindof distant shake at certain rpm. it should not shake the mirrors but will be felt as a rubbery vibration that is not bothersome but notes that you do indeed have a five and not the four.

when you put a 300 into a 240 you need to remove the L shaped bracket that fits into the back of the deep oil sump on the 240 motor. if this is neglected there will be a pronounced vibration like a bad motor mount but much much worse. it is literally the motor sitting metal to metal on the frame. yikes! it is very harsh and will shake everything.

so if you didnt remove that, you need to do so before anything else.

if the center bearing is bad there prob will be some play at the center bearing so push up and down there on the ds and see if it is loose.

the type of fluid in the stick tranny is i think probably a flyspeck in the overall picture and wont cause any vibration that is measureable by the most experienced and sensitive butt.

and finally if you didnt put the second shock mount on the engine mounts, do it. they put two on there for a reason and it relates to vibration.

and finally did you put on new motor mounts? the centering thing seems like a long shot to me. but new mounts are always a good idea and not too expensive, either.

when we finally got everything sorted on my 83 240 with na euro 300 it was so smooth you would swear it had a six.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.