250 automatic engine replaced with 230 manual - flywheel, what should I check.

[rgafitanu@gmail.com]

Under previous ownership my car had the 250 engine replaced with a 230. The data card shows 129981-12-000087 and the engine is 127981-10-003669. The obvious difference is that the donor came from a manual. Without getting under the car I assume the transmission is original (automatic).
As I am chasing a 60 mph+ vibration (changed flex disc and donut) could there be a flywheel or dampener misfit between the two that I should check?

Thank you.

[ja17]

The 230 engine is a counterbalanced engine and the flywheel/dampner/ crankshaft assembly should be matched. They are balanced as a unit assembled. If you have changed anyone of the three you may have an issue.

[ja17]

Does your vibration also happen with the car at rest at higher rpm?  If the vibration only happens when the car is moving, look for an imbalance in the drive train (flex disc, centering bushing , drive shaft, wheel, exhaust, motor mount).

[Rick]

JA17 is correct. If this is an engine imbalance, and your note of a flywheel change suggests that.  The engine, dampner and flywheel are balanced as a unit and need to stay together in the correct orientation.  The mbz manual discusses "matching" the balance from the original flywheel to a replacement flywheel, but you must have an original with proper orientation to do this.  The only way to correct an engine imbalance is a total engine dissembly and rebalance.   The pistons are also required for balance of the crank, dampner and flyweel.  Certainly a pain, but an engine vibration will be an never ending irriatant. I went through this once.  Big job, but sure nice to end up with a smooth engine.

Rule out driveline by seeing if the vibration is related to engine rpm rather than vehicle speed.   Try different gears to change engine rpm and see how that affects where the vibration occurs, looking at if the vibration happens at a similar engine rpm.

[rgafitanu@gmail.com]

When I got the car 2.5 years ago, the dampener was wobbling. I pulled it out and realized that it is not in the keyed position that it should have been. Let's assume that the dampener is the correct one. Could the previous owner mount the 250 flywheel to the 230 engine, would a manual flywheel fit a fluid coupler? When swapping motors I would see someone trying to keep the automatic flywheel from the old one to replace the donor manual flywheel rather than keeping the dampener.
I checked the vibration again, it's a rolling vibration that comes every 1-2 seconds, not a continuous vibration like generated from imbalanced wheels and it's not there in park @4000 rpm or in 3rd so it must be the drive shaft. Changing the flex and the donut made it less intense. Unfortunately 3 so-called "balancing shops" told me they are not touching Mercedes drive shafts.

[Rick]

Most driveline shops do not have the stand to do a two piece driveshaft.  But some do.  This is one company that does it.   If you call around, you can find others  -   Inland Empire Driveline Service, Inc.
1540 Commerce St., Ste A
Corona, CA 92880


The same sort of thing is true for the driveshaft as is true for the crank shaft.   The two prop shafts are balanced together.   Prior to 1983, Mercedes did not mark the orientation of the two driveshafts. Hard to believe, but true.

Also check drive train alighnment.  Be sure the motor mounts are in good shape, including the rear (transmission) mount.  Check the subframe mounts.  The rear transmission mount has spacers which raise the rear of the transmission.  Be sure those are there.   Look to be sure the rear axle is sitting properly.   Check the rubber mount on top of the rear axle (The one that you can see in the back of the trunk).