With the recent diesel'ing projects going around got me thinking....

I really like the looks of the w126 coupe and I was bummed the day that I found out that they never came with a diesel.

I've got a good 617 turbo and trans from an '85 SD sitting in the garage

I found a SEC that looks in decent shape for a low price for sale kinda nearby

I've seen a couple for sale here and there but I don't recall ever seeing any project write ups about doing a swap in one of these.

I feel like I have the technical ability and the workshop space to do it.

How feasible is swapping a v8 for a diesel in a w126 coupe?

Anybody want to weigh in with reasons why or why not to try it?

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

I believe there used a guy on here who had one, in Europe? Forget his userID.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

I did mine with a 603. Easy.
380 SDC

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Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO

I't probably would be better with any 60x engine but I already have a engine sitting there taking up space.

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

if you don't have a donor car to swap things over from, it can be tricky...

come by my place and pick up a donor vehicle...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

This sounds like the modern-day siren call that would lead sailors to their doom!

Phil Forrest

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1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

No reason at all not to do it, would be a cool car!

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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission.

Yer thinkin' cho. He'll probably see this about five hours from now .

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"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

I would really love to convert an SEC, and would use a 606 engine.

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'98 E300 DT
'87 190D 2.5 turbo RIP
'92 S500 Sold
'03 3.2TL-S A-Spec

PhillyTwoTank: If you're looking for an answer to the question in your title, I think you clicked on the wrong subforum .

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"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

Forward of the firewall the only difference between a 126 4-slammer and a coupe is a slightly lower hoodline on the coupe, and the obvious headlight and grille differences. Hence, the engine is a bolt-in using all the 300SD bits; and then dealing with any possible hood interference resulting from engine height.

was another one in Canada, the owner (on this forum) bought it already done, here in Texas and took it back to Canada. Had it up for sale, seems like it was a few months ago. Seemed like a real nice one, and seemed like it was priced real fairly too. He claimed he had never driven it in the winter as I recall and always garaged kept. Wonder if he had any luck in selling it...

I digress, I think it's a great idea and I also think it should be very do-able, as in not too terrible difficult, should be able to use all OEM pieces from any w126 diesel. There is only one thing I could "share" with you on doing the swap: You may have to do some firewall "massaging" with a BFH. I know an individual you swapped an OM617 into a mid 80's 420SEL (about an '87, I believe) he informed me that all was pretty much a direct swap but he did have to "customize" the firewall for some minor clearance issues. Beyond that, I can't offer any more greater detail at this date, it's been awhile...

The w126 Coupe diesel swap has been done before.

Diesel SEC swap begins today.


Converting An SEC?

How to convert a GAS W126 to diesel, the definitive thread hopefully.

617 engine transplant into SEC, SL, SLC


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

.

Just do it mate


best option is to have complete donor car (if you go 617a way)
generation also has to match....
it is easy and it is fun

if you gonna 603/606 way you will have to play a bit with
instrument table/transmission/diff....
.

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w126 500SEC gen II euro, powered by OM617 turbo stolen from 84 300SD 2.88 diff,EGR blinded
next wish/project: w114 coupe OM603 powered

if you have a 617a and tranny you dont really have to have write up
as it bolts directly.
depending of generation of your SEC it will have 2.24 or 2.47 diff. first one is
too high for 617a 2.47 is ok but I will advise 2.88 for optimal usage.
also you will have to acquire instrument table from 300sd for correct readings.

the important thing is .... everything bolts/plugs nicely
(well only diff is not matched between generations)


the reasons for swap...well if you have superb V8 and plan to drive weekends only dont touch it,....but if the engine is not in so so condition,maintenance and consumption will be the killer of the car.

cheers
ChO

.

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w126 500SEC gen II euro, powered by OM617 turbo stolen from 84 300SD 2.88 diff,EGR blinded
next wish/project: w114 coupe OM603 powered