interchangeable engines?

[rocktower]

Greetings all. I'm new to the forum here and new to the Mercedes diesel so I'd apreciate your patience and input in what I'm trying to figure out. I've got a 1980 240D engine, manual trany, and drive shaft. I'm wondering if it will bolt onto a 300d or any of the other 123 chasis with little or no modification. thanks

[layback40]

Hi rocktower,
welcome to the forum.
Interesting wanting to put a 240 into a 300D. normally people want to go the other way. It should work. It would fit into any w123 but a diesel body is the easiest as everything will be there. The clutch for the manual will be a challenge as most are auto. You will need to organize a clutch peddle & master cyl for it.

Good Luck
i am sure others will tune in with more info for you.

[t walgamuth]

Best to start with two complete cars. There are a lot of differences some major some small. including radiator, engine shock mounts, glow plug relay. speedo, drive shaft, pedal cluster and rear end. It is all straightforward. I have done a couple of conversions from 240 power to 300 power, both in the 115 chasis and the 123 chassis. I estimate my Indie would charge me about 15 to 1700 usd to do all the labor.

Nothing is very complicated but it is a lot of work for a hobbiest to complete and much of it is made easier with a lift.

[charmalu]

Welcome to the forum.

Yes your engine, transmission and drive line will bolt right in.
You will need the transmission skinny steel cross mount.
The manual shifter will bolt right in where the auto shifter is mounted. just 4 bolts.
The 80 came with the iron box 4 speed, the shift rods will bolt right in, unless you source rods from the later all one piece aluminum box. I think those rods are bent a little different. the alum box was used in the 82 & 83 240D.

The peddles are no big deal to R&R. 4 13mm nuts hold the assembly on from under the dash. remove the pin and rod off the brake peddle first.

The master cylinder bolts to the peddle assy. I would use a new MC along with the slave cylinder.

The 80 240 uses the pencil glow plugs, so if you install the eng into a 82 - 85 123, I don`t know why you couldn`t use that GP relay minus one wire from the relay.

I would think you could use the radiator and oil cooler also. the eng has a thermostat as well as the oil filter housing. so it shouldn`t run too cool.

The 240D uses the 3:69 differential. a 300D na uses the 3:46. 82 - 84 300D turbo uses the 3:07 and 85 used the 2:88.

There is a reason the 240 uses the 3:69.
Don`t expect the 240D to be a race horse, it is only 67HP.

The spedo is geared to the Diff., so if you change ratios, get the spedo from the donor car also.

I haven`t done an eng swap from 300 to 240, but have R&R my 300 eng. and done a 4 spd swap into the 85.
I sourced all my parts from PNP at different times before I did my swap. so in my case, didn`t need a donor car sitting in the driveway.

Some one else should chime in and add to this.


Charlie