Need swap info on 617 engine - PeachParts Mercedes-Benz Forum

soothappens · #1 03-17-2010, 09:08 PM

I bought an 82 model 300SD with a bad engine looked at a bunch of engines the same year or newer all where in bad shape. At least the ones close by.

Driving home I came across a 80 model 300SD with low miles . Got it to turn over by hand but battery is dead . I'm going back with a battery to try and start it but first I wanted to check if the engine and transmission will work in the newer 81 SD.

Can anyone tell me what the differences between the two years are?

It seemed the same. The only thing I noticed was the transmission linkage.
I have tried the search but most threads were on a 617 into a 240.

Any help is appreciated.

vstech · #2 03-17-2010, 09:09 PM

I believe the oil filter canister is different.
otherwise it should work well.

JEBalles · #3 03-18-2010, 09:08 AM

I have an '80 or '81 300SD engine (I'm not sure which one, body was a W126), is the oil filter housing the same for those and the W123's? It looks similar, but I can't be sure.

vstech · #4 03-18-2010, 09:12 AM

no. the 123 has a mechanical fitting for the oil pressure gauge on the oil filter housing. the fitting may be swappable, but I do not know.
I think 80 was the last year of the 116 SD and 81 was the first year of the 126SD

soothappens · #5 03-18-2010, 10:01 AM

Quote:

Originally Posted by vstech

no. the 123 has a mechanical fitting for the oil pressure gauge on the oil filter housing. the fitting may be swappable, but I do not know.
I think 80 was the last year of the 116 SD and 81 was the first year of the 126SD

Yeah thats why I asked . The body its in is a 116 the one I have is a 126. The engine seemed similar but the transmission was missing the vacuum box on the valve cover and the cruise and throttle linkage was different. Possibly speedometer change as well ?

After further research I found the 80 model has less HP but the same torque I dont understand that one either ?

So basically this will drop in and run but possibly have clearance issues near the second fire wall of the 126 due to oil canister ?

Going to try and start it now.

Thanks for the reply !

Graplr · #6 03-18-2010, 11:26 AM

I replaced the engine and tranny in my 84 300SD. I bought a 1980 300SD (116) and pulled the engine and tranny from it. The engine turned out to be a replacement engine from a turbo 300D and the tranny was the original 722.120 from the 116.

The engine is currently in my 126 with no problems. I know it is not the same exact engine from a 116 but it worked in the 116. I swapped power steering pumps, oil fitler canitster (electric in the 126 unlike mechanical in the 116), compressor (I knew mine worked), and alternator.

I could find no practical way to swap the tranny easily. I ended buying one from a boneyard and 20k miles later it is still working.

I think the tranny will bolt up but I think I would have had to alter the driveshaft in the 126, I don't recall for sure. The bigger issue was the mechanical speedometer on the .120 tranny vs the electrical on the .303 that is stock on my 84. Also, I bought an 83 tranny and now my tach no longer works as the pick up for pre83 was front of engine and 84 up were in the tranny. I tried swapping the pickups at the engine but I haven't gotten it to work.

So in short...the engine should work no problem. I would swap the accessories. The tranny MAY work with some major alterations. But it seems you may have a good tranny your 126 anyways. Pretty sure that tranny will bolt up to the 116 617 engine.

Graplr · #7 03-18-2010, 11:30 AM

Quote:

Originally Posted by soothappens

Yeah thats why I asked . The body its in is a 116 the one I have is a 126. The engine seemed similar but the transmission was missing the vacuum box on the valve cover and the cruise and throttle linkage was different. Possibly speedometer change as well ?

The speedometer gets its pickup from the tranny. If you use your existing 722.303 tranny in your 126 it won't matter. If you get the 722.120 tranny from the 116 to bolt up in there you wont have a speedometer. There is a kit out there (PM Brian Carleton) that converts the mechanical signal to electric but I think you will have bigger issues than that in trying to use that tranny. I would just use yours.

Quote:

Originally Posted by soothappens

After further research I found the 80 model has less HP but the same torque I dont understand that one either ?

Pretty sure the lower horsepower was ONLY in the 79 116 models. The 80 116s had roughly the same HP as the 126 engines.

Quote:

Originally Posted by soothappens

So basically this will drop in and run but possibly have clearance issues near the second fire wall of the 126 due to oil canister ?

Going to try and start it now.

Thanks for the reply !

There should be no clearance issues putting the 116 engine into the 126. There may be possible clearance issues going the other way (126 into a 116). I believe the bottom of the 126 engine hits the crossmember in the 116.

Good luck!

Graplr · #8 03-18-2010, 11:33 AM

Quote:

Originally Posted by JEBalles

I have an '80 or '81 300SD engine (I'm not sure which one, body was a W126), is the oil filter housing the same for those and the W123's? It looks similar, but I can't be sure.

A 1980 300SD was the 116. A 1981 300SD was the 126.

The oil filter canister in the 123s are exactly the same as the 126s, BUT the 126 has an electrical oil pressure sender on it where the 123s have a mechanical sender on it.

Graplr · #9 03-18-2010, 11:34 AM

Quote:

Originally Posted by soothappens

It seemed the same. The only thing I noticed was the transmission linkage.
I have tried the search but most threads were on a 617 into a 240.

All you have to do is swap the valve covers when you swap engines. Problem with linkages and vacuum connections solved.

soothappens · #10 03-18-2010, 07:37 PM

Quote:

Originally Posted by Graplr

I replaced the engine and tranny in my 84 300SD. I bought a 1980 300SD (116) and pulled the engine and tranny from it. The engine turned out to be a replacement engine from a turbo 300D and the tranny was the original 722.120 from the 116.

The engine is currently in my 126 with no problems. I know it is not the same exact engine from a 116 but it worked in the 116. I swapped power steering pumps, oil fitler canitster (electric in the 126 unlike mechanical in the 116), compressor (I knew mine worked), and alternator.

I could find no practical way to swap the tranny easily. I ended buying one from a boneyard and 20k miles later it is still working.

I think the tranny will bolt up but I think I would have had to alter the driveshaft in the 126, I don't recall for sure. The bigger issue was the mechanical speedometer on the .120 tranny vs the electrical on the .303 that is stock on my 84. Also, I bought an 83 tranny and now my tach no longer works as the pick up for pre83 was front of engine and 84 up were in the tranny. I tried swapping the pickups at the engine but I haven't gotten it to work.

So in short...the engine should work no problem. I would swap the accessories. The tranny MAY work with some major alterations. But it seems you may have a good tranny your 126 anyways. Pretty sure that tranny will bolt up to the 116 617 engine.

Thanks for this and the remainder of your posts. Very informative.

I thought I remembered reading about the speedometer some where just wasnt to sure.

Well went to check it out at lunch . Cranked spun over well but smoke was chugging out of the valve cover worse than my worn out 240 never did start.

Back to looking !!!

Thanks again for all the info !!

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