Can I convert a 1971 280 SE to Diesel?
 

Hi, I'm new to the forum, and have a maybe crazy question to ask.

I'm thinking I'd love to start running my W108 on biodiesel...for a number of reasons I don't need to go into here. But of course it's a gasoline engine (244 K miles and still solid, gotta love that). Any hope of finding a turbo diesel engine from a later model Benz that'll fit into mine? And if so, any hope of getting somebody to do the work? Finally, what's a rebuilt engine going to cost?

Thanks

CAN you or SHOULD you?

Gilly

NO! Never!

Concur. For the money you'd spend to do it even halfway correctly, you could get a fine 300D or 300SD turbo.

Gas to diesel swap for the W108 was fairly common in Europe, dropped both fuel consumption and taxes considerably.

It's quite straighforward -- the engine will fit directly on the mounts, and I believe even the driveshaft is close.

Not free, though....

Peter

I know, I know
 

Well, I knew it was crazy, I just love the body of the W108 so much. The idea of selling it to get a newer, less lovely diesel seemed to bring too much pain.

So, at the risk of making everybody gag, if I want to explore the idea further... Which engine(s) would be the one that "fits directly on the mounts," and is a driveshaft that's "pretty close" a euphemism for "mechanic run screaming from the shop in disgust?"

I'm certainly not willing to spend what the car is worth to create Frankenstein, but if they did it a lot in Europe....

Thanks everybody, by the way, this is a great resource for me to learn from.

Yianni

I would try the non-turbo 5 cylinder model for starters. A turbo is tempting, but I wonder if that would just cause additional challenges. But you should get some better advice, since there could be some "fit" problems like air cleaner or oil filter housing problems to avoid.

Whatever you choose, get an engine and transmission together. It would also make sense to start with a 114/115 or 123 parts car, since there are a number of peripherals you will need - like the vacuum controls for the transmission, throttle linkage, vacuum ignition switch, glow-plug wiring, etc.

Vertical oil filter cannister on later model diesels has to clear the steering shaft. That's the reason 616/617 engines after 1978 wont fit a 110, 111 or 115. Dunno about the 108, but there was actually somebody in Texas who set up a shop for diesel 108 conversions long time ago. He closed his doors because he couldnt capture a large enough market to stay in business.

I'd like to see how it's done. The fact that development of the 5 cyl engine missed the 108 by just a couple of years is a tragedy. Snag a rustbucket 300D and Go for it!!!

<edt: But you gotta be reluctant to give up that perfectly good 244k mile gasoline engine.

617 turbo drops right in. So will a 603, a better choice if you can find one. The 603 would greatly benefit from a 4.5L rear end (3.23), and one from a 6.3L would be even better. Driveshaft will be very close on those models.

ALL MB engines from the middle 50s on will fit on the engine mounts, but some will be more trouble than others (you will need to chang the "arms" (aka engine carriers) to the ones from the original engine).

Peter

I saw a 250S at a cross country meet of mine. I the lady and her husband bought it for their 16 year old daughter. It had an engine that looked to be either a 200 or 220. Maybe, it was the 2.4. I remember it having the long tubing running along the valve cover like the previous engines. It also had a stick. It had a hose running into a pop bottle for brake fluid, so I would fix that if I owned it first. I remember leaving on our bus, and seeing them trying to start it. They were probably oblivious to the function of glow plugs or how to engage them. I would have helped, but I was no our school bus driving away.
-David