More vibration and clattering on acceleration - PeachParts Mercedes-Benz Forum

ambush276 · #1 05-20-2016, 01:27 PM

Hey all,

I just installed my new clutch (resurface flywheel, plate, pilot, disc, throwout, Trans mount) and right now the car shakes much much more when cold and is louder and less smooth on acceleration. I actually now have to turn the idle adjust nob down (less rpm) for the car to be smooth at idle (before I always had to be at maximum). Is this normal? Do I need to break in the clutch? It is much louder and the car has muxh more vibration than before. (And idle has to be less rpm ...bizzare?). It does catch nicely on the clutch and gear shifts are very smooth and no weird sounds during the shift itself (beyond the added vibration).

1982 240d, manual trans

Thanks.

leathermang · #2 05-20-2016, 07:11 PM

Shakes more when cold at idle and the clutch pedal pushed IN ?

ambush276 · #3 05-20-2016, 08:00 PM

no. clutch pedal pushed in it shakes the same. Idle is not as bad as accelerating. During acceleration it is by far the worst (higher RPM is the correlation to the vibrations. Coasting in neutral is fine.

Frank Reiner · #4 05-20-2016, 08:34 PM

Is the increase in vibration associated with engine speed, or vehicle speed?

ambush276 · #5 05-20-2016, 08:53 PM

engine speed. At higher speed it is still vibrating more than before the clutch job, but at higher speed it is less horrible. The real bad times are fast idle (when the nob is all the way up) in neutral when the engine is warm and during acceleration. I have to turn the fast idle down a lot and then the vibrations drop dramatically (when warm).

leathermang · #6 05-20-2016, 10:04 PM

Was the flywheel put back on the crank in the same position as it came off ?

Was the flywheel balanced after being surfaced ?

Frank Reiner · #7 05-20-2016, 11:46 PM

Quote:

Originally Posted by Frank Reiner

Is the increase in vibration associated with engine speed, or vehicle speed?

Quote:

Originally Posted by leathermang

Was the flywheel put back on the crank in the same position as it came off ?

Was the flywheel balanced after being surfaced ?

Quote:

Originally Posted by ambush276

engine speed. At higher speed it is still vibrating more than before the clutch job, but at higher speed it is less horrible. The real bad times are fast idle (when the nob is all the way up) in neutral when the engine is warm and during acceleration. I have to turn the fast idle down a lot and then the vibrations drop dramatically (when warm).

Since the crankshaft, the front hub, and the flywheel are originally balanced as a unit, the balance will be impaired if the flywheel is re-installed in other than the original position on the crank.
The imbalance will be felt as a function of engine speed.

vstech · #8 05-21-2016, 06:48 AM

It's also possible you damaged your motor mounts during the swap. Make sure they all stand tall.

ambush276 · #9 05-21-2016, 12:29 PM

mounts look a little worn. I am going to look at the car later this week on a lift, will report back after that.

ambush276 · #10 05-31-2016, 02:21 PM

i replaced the motor mounts with lemfoerder mounts. There is still some vibration and a little bit of a clunk when starting and stopping the motor. Could engine shocks be the issue here? It still feels a lot of vibration on high idle (a little better than before). Also, although these are new mounts... how can i tell if they are collapsed or not. Idk why.. but they seem to be riding a bit low to me.. eventhough they are brand new (and lemfoerder).

barry12345 · #11 06-01-2016, 01:28 PM

If this was a manual 240d before you did the clutch job and I think it was. I believe the flywheels where neutrally balanced on some and not on others. Hard to get a clear picture on this.

My understanding is that there Is only a very faint reference mark on them for correct orientation. Obviously you pulled the flywheel for resurfacing. If you paid no attention to positioning when removing and remounting the flywheel there may be a balance issue here. Some members have claimed that mark is really so faint on 240ds it is hard to even find.

Always mark orientation with a punch or paint when pulling and installing flywheels if you do not locate a mark. Personally I have never done a flywheel removal and re installation on a 240d. Since you have issues with the clutch disengaged it is either the flywheel orientation or a real imbalance in the pressure plate creating the change. Not a great chance of a new pressure plate assembly being imbalanced.

BWhitmore · #12 06-01-2016, 03:23 PM

Hopefully you installed the clutch disc and pressure plate as a balanced set. Installing a mismatched clutch disc and pressure plate can also create a vibration in addition to a flywheel that was not indexed to the crank.

Frank Reiner · #13 06-01-2016, 03:29 PM

Quote:

Originally Posted by barry12345

I believe the flywheels where neutrally balanced on some and not on others. Hard to get a clear picture on this.

The above conclusion is easy to reach; all MB inline engine assemblies (crankshaft, front hub, flywheel) are balanced as assemblies. Some, randomly, may not have required any drilling of the flywheel and/or the front hub to achieve the desired state of balance. The existence of a "neutral" flywheel is a matter of chance, rather than a matter of design.

See Post #7.

leathermang · #14 06-01-2016, 04:01 PM

I am worried about the ' clunk' at starting and stopping the engine...
If that is a loose flywheel that is dangerous...

ambush276 · #15 06-01-2016, 05:46 PM

im pretty sure that was all aligned correctly and that the flywheel is not tight. The most bizzare part is that the smoothest idle is at 2/3 fast idle. If i move it up to fastest idle... there is a lot of vibrations... too low and the engine is bouncing around. 2/3 up is the smoothest and quietest of the bunch. Could be something tranny related.. but I am pretty sure everything was balanced and reinstalled correctly.