Swapping 240d motor for 240d motor questions - PeachParts Mercedes-Benz Forum

Schmanman · #1 03-18-2015, 03:38 PM

I have a one owner 1983 240d in immaculate condition, but with a bad motor. I located a nice motor to use as a replacement, but its off of a car with a manual transmission and my car is an automatic. I intend to re-use my automatic and that is what raises questions.
I have heard that the flywheel needs to be balanced for the motor. I have also done enough research to know I must take the (automatic) flywheel off of the bad motor and put it on the good motor in place of the manual flywheel.

I have had some people say the flywheel is okay as long as it is neutrally balanced, but others have told me I had to have the auto flywheel re-balanced for the new motor before I put it in. It seems most move up to a 5-cyllinder instead of simply replacing the motor, so I'm having trouble finding good information. do I need to balance my auto flywheel for the new motor before I put it in?

Thank you,
Alex

junqueyardjim · #2 03-18-2015, 04:58 PM

If it were mine Alex, I would go ahead and put it on and forget the balance problem which I don't think is a problem in your case. You are going to use the automatic transmission and that flywheel is light and the torque convertor also tends to eliminate vibration. I made a similar but different switch, taking out the 240D and installed a 300D turbo and kept the four speed manual. Didn't balance anything and it is perfect. There is a small chance that on the swap I made that things could have backfired and not worked out as well. But with the 240D and an automatic, I would say, "just do it". Remember though that when switching the flywheel on that 240D, some of the flywheel bolts are of the stretched neck type and are suitable for single one time use only. My thinking there is that if the flywheel bolts for the automatic flywheel are very short, they can be re-used.

cfh · #3 03-18-2015, 05:05 PM

A 240D with a standard is a very nice car to drive - I'd swap the whole thing.

Schmanman · #4 03-18-2015, 05:48 PM

I would convert to a manual, but the manual trans that came with my replacement motor slips in second gear, and my budget is too small to purchase another. Plus I would have to locate parts for the clutch & shifter.

I have another question pertaining to the swap. I have rebuilt several 1970 dodge chargers and have experience swapping 440 ci motors. Those cars were manufactured with unbelievably bad build quality compared to the 240d, which makes me wonder if this swap would be easier. I know the Mercedes has a lot more room underhood and access to the trans bolts is much better than it is on old mopars. I was planning on having a shop drop the motor into my 240d for me once I clean, polish and paint it but given my access to equipment and prior knowledge swapping motors, is this a project I should take care of myself? I wouldn't mind the opportunity to clean up my engine bay, I'm just unsure of the complexity of the swap and the difficulty of mating the motor and trans.

Schmanman · #5 03-18-2015, 06:00 PM

Frank Reiner · #6 03-18-2015, 06:15 PM

JYJ's approach notwithstanding, at minimum, mark the location of the manual trans flywheel on its crankshaft, and then have the balance of that flywheel checked. If it is neutral, then the autobox flywheel can also be made neutral (if it is not already). If the flywheel of the manual trans engine is not neutral, then the autobox flywheel should be imbalanced to match, and installed to the crank in the same relationship as the manual flywheel.

The engine change effort will be no different than what you experienced with the Mopars.

gatorblue92 · #7 03-18-2015, 08:34 PM

If you can rebuild old Mopars then you are more than qualified for this swap. I recently swapped my auto for a 4 speed in my 77 240D and it was the biggest job I have undertaken. Here is the thread on my swap. It might help...

240D refresh time

Quote:

Originally Posted by Schmanman

I would convert to a manual, but the manual trans that came with my replacement motor slips in second gear, and my budget is too small to purchase another. Plus I would have to locate parts for the clutch & shifter.

I have another question pertaining to the swap. I have rebuilt several 1970 dodge chargers and have experience swapping 440 ci motors. Those cars were manufactured with unbelievably bad build quality compared to the 240d, which makes me wonder if this swap would be easier. I know the Mercedes has a lot more room underhood and access to the trans bolts is much better than it is on old mopars. I was planning on having a shop drop the motor into my 240d for me once I clean, polish and paint it but given my access to equipment and prior knowledge swapping motors, is this a project I should take care of myself? I wouldn't mind the opportunity to clean up my engine bay, I'm just unsure of the complexity of the swap and the difficulty of mating the motor and trans.

charmalu · #8 03-18-2015, 11:51 PM

I don`t know ....with all that Rust and Bondo, really not worth fixin. Give you $400 bucks for it... scrap value.
Be by with my trailer and drag it out of your driveway.

Just Kidding, you have one beautiful 240D. Wow!!!

I would do as Frank Reiner said, just to be safe.

If I were doing the job, I would pull the engine and trans together.
Then you can do the swap on the ground. Just be sure to remove the 6 13mm bolts that bolt the FW to the Torque Convertor, before pulling the eng/trans. That one tripped me up one time.

The Hood will go straight up, (the German salute

) then if you just want to pull the engine only, makes it easy.

If you have the donor 240D, I would strip it and keep all the parts for a manual swap if you decide down the road later on.

Charlie

Schmanman · #9 03-19-2015, 02:13 AM

Thank you so much for the help everyone. I'm excited to clean the motor bay up. Do you think I could get the motor swapped out in a day or two? I feel like it's very plug & play past the flywheel.

junqueyardjim · #10 03-19-2015, 03:55 PM

"I would convert to a manual, but the manual trans that came with my replacement motor slips in second gear, and my budget is too small to purchase another."

Alex, that quote is not correct if that transmission is a manual 4 speed. It could have a problem getting or shifting into second gear, but a manual transmission can not slip in gear. It can make some strange noise, even growl, but slip it can not do. It does make me wonder if you are capable of the job.

As far as swapping the unit in and out, if or as long as you don't change the transmission type, (from auto to manual or the other way around), and if you stay with the 240D in and out, and you have some experience and you have a good engine hoist and decent tools, it can be a week end job. But it is a lot of work, say that again, it is a lot of work!

sixto · #11 03-19-2015, 04:13 PM

Can a MT IP be adapted to work with a VCV or will the IP have to be swapped as well?

Sixto
MB-less

junqueyardjim · #12 03-19-2015, 04:55 PM

Sixto, you got smoke in your eyes I think.

Schmanman · #13 03-19-2015, 05:05 PM

Quote:

Originally Posted by junqueyardjim

"I would convert to a manual, but the manual trans that came with my replacement motor slips in second gear, and my budget is too small to purchase another."

Alex, that quote is not correct if that transmission is a manual 4 speed. It could have a problem getting or shifting into second gear, but a manual transmission can not slip in gear. It can make some strange noise, even growl, but slip it can not do. It does make me wonder if you are capable of the job.

As far as swapping the unit in and out, if or as long as you don't change the transmission type, (from auto to manual or the other way around), and if you stay with the 240D in and out, and you have some experience and you have a good engine hoist and decent tools, it can be a week end job. But it is a lot of work, say that again, it is a lot of work!

I apologize, I didn't explain clearly. The transmission is very difficult to get into second gear. I prefer to go with the automatic at the moment anyway. Thank you for the advice! I have access to a full service shop with a lift and plenty of man power so I'm not too worried about the swap.