300SD engine into 300D and vice-versa?
 

Hi...I may have found another engine for my dear departed 300D original blown engine...but the motor I found is for a 300Sd, not 300D. I'm curious about whether I can put this in my car...one gentleman on here noted that I would have to swap the oil filter housing because the 300D uses a direct line to the pressure gauge, where the 300SD is electronic. he also mentioned I'd have to use different motor mount arms...is the casting on the block different between the D and SD? I would be surprised if it were. Any other changes one has to be aware of? Thanks in advance...

You should just need to swap over your existing 81-85 W123 motor mount arms to the engine from the 81-85 W126 300SD.
Also you should be able swap in your direct oil pressure gauge feed line to the oil filter housing on the W126 300SD by removing the sender from the W126 oil filter housing.

The valve cover mounted throttle linkages might be different as well.
If the W126 engine is from 1985, you will also need to swap in your existing turbo and intake and exhaust manifolds.

Another thing to take note of is what year the SD engine is. 78-80 have a few minor differences but everything from your W123 will swap right on. W116 SD's have unique oil-pans, and they have the older transmissions (722.1?)

Yes, 722.120 on the '78-'79 IIRC. Friend of mine just bought a '79 with no reverse. Mechanic told the previous owner that it needed a transmission. We tightened the reverse band adjuster that had backed itself out completely and reverse works perfectly.

Sweet!
Score, gotta love the easy fixes.

No kidding! It's got me a little jealous, was a 2 owner car with all OG paperwork. Window sticker was in the glove box still has the German import information on it, tons of service records...the ALDA even still has the original plastic retainer cap over the adjuster screw.

sounds cool!

Back in 2001, my 85 300D engine died because someone dropped a nut into the intake. Did a lot of damage to turbo and engine.

I had a knowledgeable shop find and install a replacement engine. I believe it was out of a 1983 SD. New turbo was different from original (I forget offhand the make). Only problem I noticed, was that the engine did not have a return port to sump for the oil collected in the air cleaner. Drain is plugged and I just suck oil out at every oil change. Shop also eliminated the EGR stuff the 85 had.

Still drive that car every day! 450k km now, so about 120k on rebuilt engine. Runs well!

It's not as easy as that. You'll need an adapter to get the correct fitting, which is actually a pain to find...At least in my area. So your better off swapping out the whole housing.

It's pretty much the same. Except for the linkage going to the firewall.