Engine Swap--81TD into 78D - PeachParts Mercedes-Benz Forum

RockinWagin · #1 02-02-2004, 12:49 PM

I searched but probably didn't use the right terms. So, I am getting a 78 300D with blown engine, auto tranny. I have a lead on a 81 300TD engine to swap into the 78. Possible? Problems? Thanks, Don.

Great Boob · #2 02-02-2004, 01:07 PM

Back when I thought I was going to have to replace the engine in my '79TD an independant MB shop, which is very good, told me it would be $1,000 labor to install a replacement mill. The mechanic then said it would be about another $100 or so to put in a turbo model, said there was a difference in starters or something. So I don't think its a big problem. If Iwere replacing the engine, I'd definately want to go with a turbo.

RockinWagin · #3 02-02-2004, 01:11 PM

Quote:

Originally posted by Great Boob
The mechanic then said it would be about another $100 or so to put in a turbo model, said there was a difference in starters or something. So I don't think its a big problem. If Iwere replacing the engine, I'd definately want to go with a turbo.

Yeah, I was thinking differences in exhaust for the turbo and possibly wiring harness. I will do the work myself. Been swapping engines since the 70s but never with a MB.

driad_98 · #4 02-17-2006, 05:53 PM

How'd it go? I just brought home a new motor (euro 300D) for my 240D. Never done a motor before, but I've done an auto tranny on an '80 300D. I think pulling the engine and tranny together should be even easier. I read there are a few little mods to be done... hope yours went well!

t walgamuth · #5 02-17-2006, 06:17 PM

you reallly should swap out the rear end and speedo while your at it. i have a good wagon exhaust sysetm for the turbo motor that i probably wont ever need so i would sell it for about $100 plus shipping i suppose. it looks like new. i think it is an ansa aftermarket.

tom w

driad_98 · #6 02-17-2006, 06:20 PM

They didn't have the rear end, or for that matter, the driveshaft.

I'll get mine modified. I think I read shortened by 58cm. I could see using the taller rear end, but it's a non-turbo motor, and it came with a manual tranny and clutch, too. All with only 118K. I've got such a good feeling about it.

I just need to find an engine hoist to borrow in the bay area.

t walgamuth · #7 02-17-2006, 07:08 PM

i assumed that you were swapping in a turbo. if it is non then the rear end should be fine. so much the better if it is a stick behind it.

sounds like a great combo.

tom w

TonyFromWestOz · #8 02-18-2006, 11:27 AM

I have done a couple of 2 way swaps in W123 Mercedes Benz' cars.
The first was from an '80, into an '82 and vice versa. There were no compatibility issues as in Oz, we didn't get the Turbo (pity)
The second was to put a '78 OM617 into an '81 280E body.
I bought the 280E initially as a parts car, but was reluctant to strip it for parts because it was so nice. My wife knew someonw whose 300D had been reconditioned 2 years before, but was off the road for other reasons. I eneed up buying it to re-engine the 280E as a diesel.
As I was swapping the OM617 engine and trans into the 280E, the only issues I had were in relation to the differences between the M110 and OM617. eg, the Temperature sensor is on the other side of the engine, the 280E does not have provision to fit the vacuum shutdown valve (I used a vacuum valve from the M110, operating on the ignition circuit (which fed the ignition control module), I also needed to swap the A/Cond condensor and hose from the evaporator to the compressor, as they were on opposite sides of the engine and the threads on the condensor were different between the 2 cars.
I also removed the 280E fuel pump and filter from under the tank and replaced it with a flex hose from the tank strainer to the fuel line.

Seven days in the workshop and the swap was complete. I did not reinstall the M110 into the '78 W123 body as it had poor comp on #4 cyl. I just sat it there with no bolts in the engine mounts, but the trany mount bolted up to support it during transit. It is now at my home as a parts car.
I presented the the (now) 300D car for inspection and it was re-registered from a 280E to a 300D.

The result:
An excellent car, with a good body and excellent engine and tranny

driad_98 · #9 02-18-2006, 11:58 AM

That's awesome, Tony. I actually thought, for a moment, about throwing a 250 gasser motor in there. Saw one on ebay. Haha. Temporary insanity, your honor.

So I'm feeling really good about the swap. I don't have a shop, but the motor and tranny are under cover. I have to get to reading, as I'm sure my answers are here, but I wonder what all I oughta replace on them before I install them. The motor and tranny only have 118K. My old clutch has 272 and works fine. (I'm not sure I need to replace the 'new' one.) Plus seals. I assume it's the thing to do, but I think I remember someone mentioning that main seals on these motors are not even close to easy, even with the motor out. I'll adjust the valves. How about flushing? Is there some engine flush that's done? I think I'll start prepping the old motor for removal today. (Really necessary to drain all the engine oil?) Thanks a lot for the replies, y'all!

TonyFromWestOz · #10 02-19-2006, 06:24 AM

Quote:

Originally Posted by driad_98

That's awesome, Tony. I actually thought, for a moment, about throwing a 250 gasser motor in there. Saw one on ebay. Haha. Temporary insanity, your honor.

So I'm feeling really good about the swap. I don't have a shop, but the motor and tranny are under cover. I have to get to reading, as I'm sure my answers are here, but I wonder what all I oughta replace on them before I install them. The motor and tranny only have 118K. My old clutch has 272 and works fine. (I'm not sure I need to replace the 'new' one.) Plus seals. I assume it's the thing to do, but I think I remember someone mentioning that main seals on these motors are not even close to easy, even with the motor out. I'll adjust the valves. How about flushing? Is there some engine flush that's done? I think I'll start prepping the old motor for removal today. (Really necessary to drain all the engine oil?) Thanks a lot for the replies, y'all!

The only fluids I needed to drain were - Coolant, PS fluid and A/C refrigerant (only because of the need to change out the condensor & compressor)
Once I had the engine in and running, I confirmed that there were no oil leaks and then changed the engine oil and flter and the tranny fluid.
I did no other prep on the replacement engine.
I plan to do the valves at some time in the next month.