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'73 450SL, '83 300CD, '01 E320 4matic
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Discussion Starter · #1 ·
yes, I've searched. Someone recently posted about doing the opposite thing, or more specifically replacing a M110 with a diesel.

I am about sick of diesel engines. Mine runs great, unless it's idling. Hell, the thing starts in sub freezing temperatures without hesitation. But the Marvel Mystery Oil solution for the low compression on cylinder 5 was temporary, and we're back down to 200PSI. It pulls like a bat out of hell, but the thing shakes so bad at idle that it'll start to give you a headache.

I've done everything to try to save this engine short of taking it apart and putting new rings in it, but I am starting to think I might like a gas engine better. I can't be bothered to pull it apart. If it's coming out, I'd kind of like to put something else in there. I've swapped enough diesel engines over this past summer.

If I found a good 617 turbo tomorrow that I knew I could depend on, locally, I'd go that route, but the cars themselves are scarce in the northeast, good ones being extremely scarce. Plus I'm cheap, and people around here think that any junk Mercedes is worth at least $1500.00!!!! I looked at a funny one yesterday, had to laugh. Owner says "but it's a MERCEDES!!!" I could go on and on about what a POS this thing was, but they were firm on the price. It was worth whatever scrap is worth... This thing was nowhere near roadworthy, and not worth trying to get it that way.

Anyway, I know of a couple 260E's and 190E 2.6 cars around that are beat up but relatively low mileage and mechanically sound.

In my searches I've found various V8 conversions, manual trans conversions, 603 and 606 conversions (another possibility if I could find one), but nothing involving putting the bulletproof 103 into a W123.

Has anyone seen or done this? I have to think someone has done it.
 

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W-1-2-3 Go!
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Starter will be on the wrong side, if you plan to keep the transmission.

OM617 starter on right
M103 starter on left

Same with M102.

Why not just get a 300E if you really like the M103 engine? Your W126 300SE is the closest to the M103 variant of the W123 because of the suspension design and typical layout, and age.

The big issue you'll have to get across is the engine size of the M103. The engine has 6 cylinders and is quite long. I think the M110 is more stout, so it fits. Plus, you'll need more electronic engine management for the M103 (ECU, OVP, ICAV, FPR or MAS depending on year, etc).
 

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'73 450SL, '83 300CD, '01 E320 4matic
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Discussion Starter · #3 · (Edited)
I'd snag a transmission too.

I'm not scared of fitment, I'm currently installing a 2.0 Pinto engine in a 58 Triumph 10. LOL. (That car is funny by itself, but making it pinto powered is even funnier!)

The original 4 cylinder 987CC engine was so small that the pinto engine has to actually have the rear end of the engine somewhat in the passenger compartment to fit. It's my coworker's car, although I'm doing 99% of the work. I suggested a motorcycle engine, or the 12HP briggs in my basement

So big projects don't scare me. I just love the 123 coupe, and it'd be sweet with some extra grunt. The 124 does not have the same soul.

I was just wondering if there was anyone who has already done it, pics, videos, etc.
 

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I would take the W124 over the W123 myself. I feel like it was an improvement over the W123. What a (great) difference when I hop into the 300E. Solid, sporty, comfortable.

Why don't you go the route of the Ford engine? Maybe you could find a Turbocharged I-4. They're compact, easy and cheap to rebuild, and FAST. I believe you would find them in a mid to late 1980's Thunderbird.
 

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Discussion Starter · #6 ·
I actually have a 350/700-4R combo lying around, but I don't really want a gas hog either. This is kind of my economy car.

I thought about putting that into a beater 126 as a rat-rod though.
 

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1983 240D, 1974 240D
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do it! I vote you break this ground and complete the conversion!

all this talk about 124s! wheres the fun in that if the engine came in it in the first place? :D

Also, what car did you look at locally, was it by chance that silver 300CD? The one from the 9th circle of hell, but listed at over 2 grand?
 

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Discussion Starter · #8 ·
nope, have not seen the silver one. They're stuck on the price though? Any useful parts at all? I could use a few for my 300CD if I could get it at the right price.

I looked at a 300SD yesterday that my other half noticed driving by. Amazing how good any MB looks driving by.

It had amazing rust, even for a NY car. The interior was torn from one end to the other, and the wood was broken off from the dash- dash was cracked, instrument cluster falling out, it was a disaster. 323,000 miles, all yours for $1500 firm. If it ran well and passed a compression test, I would have offered them $250 for it. The battery was dead. End of discussion. But it was a Mercedes...
 

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people ask what I drive from time to time and I tell em its a Mercedes and omit the year to see what kind of reactions I get... especially since I am stuck in a part time $9 an hour job at the moment.
 

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nope, have not seen the silver one. They're stuck on the price though? Any useful parts at all? I could use a few for my 300CD if I could get it at the right price.

I looked at a 300SD yesterday that my other half noticed driving by. Amazing how good any MB looks driving by.

It had amazing rust, even for a NY car. The interior was torn from one end to the other, and the wood was broken off from the dash- dash was cracked, instrument cluster falling out, it was a disaster. 323,000 miles, all yours for $1500 firm. If it ran well and passed a compression test, I would have offered them $250 for it. The battery was dead. End of discussion. But it was a Mercedes...
The CD was a parts car, but it did sort of run and drive, even shifted more or less properly. I don't see it listed anymore, maybe he sold it to someone, but the guy was asking 2200 bucks, and the thing was rusted out completely with 350,000 miles on it and tons of obvious running problems. So many issues that I didn't even bother getting into it, I just thanked him and left.

When I drove it, he seemed surprised that I dared to take it out on the street, like "oh, you made it back? good deal!"
 

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89 Mercedes 300E, 91 Mercedes 300CE, 71 BMW turbo 2002, 73 BMW 2002tii, 85 BMW 635csi
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Try a M104 found in the later model W124's.

 

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Discussion Starter · #12 ·
ooooo that looks delicious.

Not much room to breathe though. If the M104 fits, the 103 almost has to. I don't think it's any longer than the 103, certainly it's wider.

I am pondering the Ford 2300 turbo idea... I hate to admit it, but the more I think about it the more I'm intrigued by it.

Those came from the factory with more than adequate power, and even built up they are pretty durable. I'm a GM guy when it comes to US cars, but the Ford has the proper front sump configuration, and they built the best 4 cylinder engine, at least stateside, for many years.

Who knows what I'll ultimately decide to do... I can't decide if it's ethical to un-diesel a 300CD as rare as they are. But then again, anything can be undone... I could just yank the thing out, grind the ridge, hone it, and replace the rings. I think that would solve 99% of its running problems.

Still open to suggestions, for sure.


That is an awesome sounding engine....
 

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There's no shame in the Ford turbo engine. It's just hard to find one... :)
 

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Discussion Starter · #15 ·
There's no shame in the Ford turbo engine. It's just hard to find one... :)
I got friends in low places... haha I know of a few.
 

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Check with your friends if they have a 2JZ instead or even better, 2JZ-GTE.
 

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Discussion Starter · #17 ·
I wouldn't go with a Toyota engine in a Benz. I'd feel obligated to install a fart can. I tell my buddy his M coupe sounds ricey all the time, I'd never live it down.
 

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people ask what I drive from time to time and I tell em its a Mercedes and omit the year to see what kind of reactions I get... especially since I am stuck in a part time $9 an hour job at the moment.
same boat, but i go a little further and tell them how it's a turbo'd model, but it's still a little slower than i would prefer. :cool:
 
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