The theory for match balancing is like this:

Take the two flywheels, or flywheel and flexplate, and bolt each one to a flange on the end of a short and straight pipe so that they are 180 degrees apart.

Now, if they are neutral balanced already, when you put this assembly on two straight rails it won't go anywhere. If one or both is not neutral balanced, it will want to roll one way or the other.

What you do in that case is drill holes around the perimeter of the flywheel you are going to use so that the assembly doesn't roll. Beware the "shaving a poodle" effect and drilling holes that are too big. When you get it to stop rolling, the new flywheel is match-balanced to the old.

Ted

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1983 240D automatic, Orient Red, 174K
1983 240D manual, Biscayne Blue, sold at 341K

Seems the 240d flywheel was not neutral balance, and of course the flexplate wasn't. I had taken two days off from work and drove like mad mileage going from "talk to this person, bring it out and we'll look" blah blah...
After finally finding a VERY PRIVATE RACING SHOP which happen to have an sd on fumigation I had found someone who could do it and happened to be a benz fan whoa!!!...This swap seems to be greatly dependant upon your location and the shops ability around you, or lack of lol. Please keep in mind that while doing the swap it is very important to source the correct people that are not blinded by the three pointed star. They will say they can do it but when they see its a mercedes they WON'T TOUCH IT. Now we are onto the driveshaft issue LOL, first shop say's "yea we can cut 4" out no problem" (btw: is 4" correct?), but when I arrived with the driveshaft......."uhhh thats a metric shaft and we can't cut it" wtf!!! here we go...So whats the deal with cutting this shaft, the front part correct? THNX!!!!!!!! I'm now only 4" away from a complete swap...

front shaft only sounds correct. if nobody can tell you the exact length to shorten i suppose i can measure the bore center spacing and that should be the amount it is longer.

does this sound correct? this would be true if the motor mount arms are identical in the 240 and 300.

tom w

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[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.

I'm using the original 240d mounts, instead of anything else...I'm aware of no engine shocks, but this engine is so smooth guys it doesn't vibrate at all!!!!!!
So im not to worried about them yet...

4" is correct.

Here is a good example of a non-neutrally balanced manual flywheel. Notice the drill holes on the right.

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Its a rainy day and Car Talk is on so I went out to my shop and examined two F/Ws, one from a "77" 240D and it has "balance " holes and no witnes mark, the other is from a "78" 240D, same thing except the holes are drilled in the Inner service where the pressure plate bolts.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"