engine swap 300sd t0 240d - PeachParts Mercedes-Benz Forum

bamabob · #1 08-21-2015, 05:21 PM

I have a 1980 300sd that has 75k on it but the body as is not worth saving. I also have a 1982 240 d that is in very good shape but I hate the performance of the 4 cylinder motor since i live in a hilly area. Has anyone swapped these before and is there any surprises that I need to be aware of.

leathermang · #2 08-21-2015, 05:44 PM

I think there are some good threads in the archives on this project...
Does the 240 have a manual trans ?
Do not kid yourself on how hard this would be... VERY hard work....
but you can see from my signature... I can understand the need for more power if in hilly areas... or needing to get onto fast freeways with short on ramps....
If you are thinking of doing it yourself.... if that is the question in your mind...
Tell us about your past experience and what tools you or a good friend nearby owns..

bamabob · #3 08-21-2015, 05:50 PM

the 240 has a manual trans but I was wanting to put the auto from the 300 in it. I assume there will be drive shaft issues to deal with. I do a lot of mechanical work, I also own a ford diesel and a porsche. I have most all tools most mechanics need and have a roomy climate controlled shop to work in.

bamabob · #4 08-21-2015, 05:52 PM

I would also consider a 116 body but I have not found one that is worth committing the time

leathermang · #5 08-21-2015, 06:03 PM

A climate controlled workshop ?
Go for it... does not matter how slow it happens like that...
the manual trans and engine might be sold for good money.... lots of people would like to have that....

Skippy · #6 08-21-2015, 06:24 PM

I have the turbo motor with the manual transmission in mine. IMO, it's the best W123 Mercedes never made. I don't understand why anyone who likes driving and doesn't suffer from some sort of disability would want an automatic transmission.

t walgamuth · #7 08-21-2015, 09:40 PM

Does the sd motor have the oil filter up top or underneath? If its underneath you may have some interference with the subframes, etc.

bamabob · #8 08-22-2015, 07:49 AM

its up top in fact the motor is almost identical to the one in the 240 except that it has one less cylinder and no turbo

Zacharias · #9 08-23-2015, 02:53 PM

Things you may have to watch out for:

- may need to use a w123 oil filter canister.
- if you have a 722.120 transmission in the SD, then you have a control rod running down to the tranny. Not sure if you will need to fiddle that to make it work with w123 body, which won't have that.
- you might have an oil pan issue (lower pan) with the crossmember, in which case you'd need to swap for a 617.952 oil pan from a w123.
- I am guessing both speedos are mechanical? If not....

There are a lot of 'mays' in there because I cannot recall reading about that particular swap, usually we are discussing issues with swaps w123 <--> w126. None of the swaps are 100 pct straight bolt-ins.

leathermang · #10 08-23-2015, 03:04 PM

Quote:

Originally Posted by Zacharias

.... None of the swaps are 100 pct straight bolt-ins.

A 123 to a 123 of very close VIN numbers has the potential for being very close to 100 percent... because they came with both auto and manual trans...so things like the brackets for attaching the clutch, etc... are on both cars....

Zacharias · #11 08-24-2015, 10:57 AM

Quote:

Originally Posted by leathermang

A 123 to a 123 of very close VIN numbers has the potential for being very close to 100 percent... because they came with both auto and manual trans...so things like the brackets for attaching the clutch, etc... are on both cars....

Sure. But this is w116 --> w123. I meant swaps across chassis.

leathermang · #12 08-24-2015, 12:28 PM

Quote:

Originally Posted by Zacharias

Sure. But this is w116 --> w123. I meant swaps across chassis.

I understood and agreed... I was just mentioning the W123 because of its relative ease...not all vehicles are made from a base model then stuff added or not based on its use... many makes the auto and the manual basic body stuff would have to be installed and or fabricated from scratch...
edit.. I guess what I was aiming for was that we see lots of 123-123 swaps... and a person might think swaps were sorta run of the mill bolt out and swap deals... but that only applies to 123-123 ... and even then only across certain VIN ' categories'....

toomany MBZ · #13 08-25-2015, 03:55 PM

Does the 116 have an electric oil pressure gauge?

f so, go with a 123 filter canister as Zach mentions.

ROLLGUY · #14 08-26-2015, 12:05 AM

I doubt you will have any oil pan issues, as the SD oil pan is more streamlined, and has a little more room than the D. The 116 should have a mechanical oil pressure gauge like the 240, so no problem there. There will be differences in the motor mount arms, so you may need to use the arms from the 240 on the 617 from the 116. Another issue will be the engine damper shocks and their mounting. You may want to forgo them, as it may not be worth the effort to fab the mounts to the 240 chassis. Either way, a 123 filter stand may be needed (the 240 one will work, you will just need to change the oil pressure line plate to the one with a turbo oil feed fitting).

Zacharias · #15 08-27-2015, 12:26 AM

I only mentioned the pan as it's an issue if you transplant an OM617 from a w126 into a w116 300sd. You have to use the lower pan from the original motor as the one on the later gen OM617 rubs on the crossmember. It isn't a huge difference, but it's there.

Don't ask how I found that out.