Will it bolt up?

[RustyRecycledT]

Last fall my timing change took a dump on my '84 300D. Needless to say, it broke things. ALOT of things. ( wallet included). Now, fast forward to today. Driving home from work I stumbled on a 1980 300D with a bad trans for a reasonable price. The engine fired right up, first crank. So I'm thinking of buying the '80 for the engine. My concern is this, will it bolt up to my trans? The '80 has an OM617.950 under the hood. The '84 has an OM617.951. I know they are both 3 liter turbo diesels, the only thing I am really concerned with is the trans mounting up. ( and possibly the motor mounts.)

Anybody know if the bolt pattern is going to be the same? I personally don't think it's going to give me any troubles, but thought I would ask before I dropped the cash. Hoping someone knows better than I do and responds before I drop the cash tomorrow.

 

[TWeatherford]

I certainly think so. Don't go on my word though, check with the guys at www.mercedesshop.com on the shopforum. One thing though, IIRC the 300D did not get a turbo until 1981, so that car may in fact be a non-turbo.

 

[RustyRecycledT]

I was thinking the same thing about the '81 being the first year of turbo for the D. To the extent that when the owner told me it was an '80 with a turbo I actually doubted him. Opened the door and checked the tag. Manufacture date 11/79. Popped the hood and sure enough, theres the turbo. Looked at the pics on my phone a bit ago, I mistyped. It's a 300SD according to the badging.

Thanks for the link. I'm going to check it out.

Anybody else have any thoughts?

 

[RustyRecycledT]

Well, let's hope for the best. I bought the **** yesterday. I'll be trailering it home on Saturday. Gives me a chance to put a load on Smaug for a change.

 

[The Warden]

I was thinking the same thing about the '81 being the first year of turbo for the D. To the extent that when the owner told me it was an '80 with a turbo I actually doubted him. Opened the door and checked the tag. Manufacture date 11/79. Popped the hood and sure enough, theres the turbo. Looked at the pics on my phone a bit ago, I mistyped. It's a 300SD according to the badging.

Thanks for the link. I'm going to check it out.

Anybody else have any thoughts?

Makes sense....an '80 300SD would have a 617.950 (which is turbocharged and doesn't have an EGR valve ), but an '80 300D would have a nonturbo 617.912. Should be a bolt-to-bolt swap, although there may be a few minor differences in the throttle linkage and vacuum fittings.

 

[RustyRecycledT]

Actually, I just got around to making the swap this past weekend. Seems that there are more differences than you would think. Glad I had the donor car to rob parts off of, otherwise I would have been in trouble.
Engine mounts,radiator,throttle linkage,vac lines,AC lines. Those were the things I was expecting. Once the engine is sitting in the car is NOT the time to find out that the adaptor plate between the engine and the bellhousing is different on the two cars. Had to pull the engine back out and swap that around between the two. The trans on the '84 D won't bolt up to the '80 SD engine until you change that adaptor. Bellhousing bolts just will not line up at all.

I'll be hooking up the fuel,vac,coolant lines tonight. Hopefully I'll get it wrapped up and drive it out.

I'll say this about the SD though, there is a hell of alot more room under that hood to work than the D. Those top 2 bolts on the trans are a bear to get to!

 

[The Warden]

Interesting!!! I knew that the SD used a different tranny, but I never even imagined that the bellhousing bolts would be different. Thank you for posting the info!!

What all was different about the engine mounts and such?

Thanks again

 

[hheynow]

I would love to buy a rusted dented and faded 81 300D NA with a good 617.912 as a back up engine for when this one fails. It starts right up and runs fine great but does burn a lot of oil. Seems that it's cheaper to replace these engines than to rebuild.

 

[RustyRecycledT]

Interesting!!! I knew that the SD used a different tranny, but I never even imagined that the bellhousing bolts would be different. Thank you for posting the info!!

What all was different about the engine mounts and such?

Thanks again

It seemed to me that the difference in the mounts was the angle and length. One was swept back a little bit more than the other.

Another thing I ran into this evening was the A/C routing. The hard lines that run between the power steering reservoir and fuel filter won't fit on the older of the two engines. The offset of the pulley on the PS pump combined with the thickness of the bracket that bolts it all together just won't allow it. You have to use the one from the later model engine.

Wierd, but you also have to use the banjo bolt for the ALDA from the older model engine. The later model one is 1.5 inches long, where the older one is 3/4 inch. The longer one won't fit. Trust me.

All in all, I've spent alot of time backtracking, robbing parts off the busted engine to make the working one fit correctly. Good thing I have alot of space, lights,heat, and BEER!