early/late w123 differences

[kchristopher]

I have found a rustbucket 79 240d with 4speed manual about 300 miles away that could donate its running gear to my 82 240d/auto (complete, but with siezed engine).

I've read numerous threads on swaps on the board and realize there may be some differences in design between early and late, but I can't find a thread that lays out the differences and what is considered early rather than late.

In this particular swap, does anybody know what challenges I would face? I'm guessing it wouldn't be too hard, having two complete cars, but I also realize some things are as plug-n-play as others.

Any insight appreciated.

[adamb]

Having two complete cars, you will have everything you need, so swap away!
I know there is a lot of info on this board about this, too, and assume you are searching it.
Good luck!

[kchristopher]

Thanks Adam. Yes, I've done some searches, but haven't found anything specific. For instance, I know there was a glow plug change at some time, not sure what year (this I could probably find with another search). But what other differences am I completely unaware of?

BTW, nice to meet you. I'm in Jackson.

[Rick Miley]

The 77-79 models are early, 80+ models are late. Yes, the 79 has serial glow plugs. It may also have a different air conditioner compressor, in a different place on the engine. It won't have an EGR, the accelerator/injection pump linkage will be different, and it has a vacuum actuated cruise control. Early automatics also had different control devices than late ones. Are you going to put the manual transmission into the good car?

BTW, there are a number of interior differences as well. Grain pattern on the dashboard, seat and headrest shape, gauges are non-metric in the early ones, slightly different climate control pattern. Can you tell I've been junkyard shopping for parts?

[kchristopher]

Originally posted by Rick Miley
Are you going to put the manual transmission into the good car?

Yes, that was the intention. In fact, that is the only reason I was considering this car, given its distance from me. I've found a local 1980 300d that I was going to use for the swap, but the lure of a manual tranny is stronger than the extra cylinder.

I'm curious, were there many changes on the block/head? Would it be possible to swap over the later style accessories? I realize there is a conversion kit available for the GPs.

I guess changing the timing chain would be a good idea while the motor is out of the car.

[BF_JC230]

this is just my opinion but i would given time and space tear out what you want - label everything and take photos - cheap insurance....and set it out,make repairs, adjustments...take out your current gear out of your good shell and then swap...if your up to the "challenge" of teh swap then any little gremlins that pop up you more than likely can solve no problem - i have helped a few friends convert over volvos, corrados, MBs, and a host of american cars...as long as you have more than you need (in your case whole car -excellent) you should be fine.

our easiest was a 84ish volvo sedan in great shape - went from NA to turbo from a rotted out wagon, no problem.

-Jake

[adamb]

kchristopher ,
I noticed that you are in Jackson, MS. I am at the Navy base in Meridian, MS.
Do you know of any good wrecking yards or pick-and-pull places out your way that have Mercedes like our 123s? I've got an 85 300d-t
Thanks, Adam

[kchristopher]

Unfortunatly not, Adam. This car is my first venture into Mercedes ownership. The guy I got the car from wasn't aware of any good yards either, but isn't exactly a yard-crawler.

[silverfishk8]

i would see if it is possible to drive the rust bucket to the site of the swap. when i did a similar swap, it was very helpful to have them both there, incase you lose a bolt or line, or need to transfer some other small things.

you should us the accelerator linkage from the 79, but you may have to use a part of it to connect to the CC unit (which you should take from the '82). the reason for this is the mechanical vs. vaccum modulation (if i remember correctly...)

the exhuast system may be different for a 300D turbo also, another reason to have both cars present.

the radiator from the 82 will have tranny cooler lines, but you can use it anyway, unless the '79 is in better shape. when you do the swap, it is easier to leave the oil cooler attached the the engine and pull it with the motor.

the driveshaft will need to be swapped. you may want to get new flex plates while you are at it. the rear diff will have different ratios, but you can leave it anyway.

the installation of the clutch line and pedals is not too bad. everything is predrilled, you just have to remove the entire brake/clutch pedal assembly from the '79 and swap it into place in the '82. removing the clutch lfrom the slave cylinder may be difficult (if rusty), so take care not to break it (or go ahead and order a new one).

the speedo cable from the auto should work in the manual tranny, mine did..

i cant think of anything else, but im sure others can.

good luck.

[BF_JC230]

ageed

re reading my post i see that i was not too clear...it is a HUGE advantage to have both cars...no doubt...what i was trying to state was to have them both side by side for the conversion.

the volvo we did it that way, the corrado - no. and it was a bit harder, that was a G-60 turned VR6 in three days, but there was alot of work and making of parts to convert from just a passat power train, and snippits of VR6 corrado parts.

if you can have both handy, youll have less headaches and late nights.

Jake