I searched this site, as well as google, and it seems the conversion from gas to diesel is popular and well covered, but I could find nothing on converting from diesel to gasoline.

My car is a 1982 w123 300td. The engine I want to use is the M103. It's not a perfect engine, but I think it's a good enough and meets my goals. I thought about a V8, but I can't convince myself it's OK to do all this work for 10mpg decrease... even if its 150hp increase...

What does it take to do this conversion, as far as making the engine work in my car? I mean things like ignition, wiring, fuel delivery, etc. I'm thinking about finding a w123 280E at the wrecking yard to get any and all needed parts, but I'm not sure what I need or don't need. Do I need to change the fuel tank? Fuel lines? Buy a 280E fuel pump? What about the engine electrical stuff? I'm willing to do the work, and competant/capable, but I just need a little guidance.

I'm not worried about mounting it - I'll use a 300SD transmission which should connect to my driveshaft, shifter, mount, etc. I can weld, so I'm going to fabricate custom motor mounts for the engine, and custom exhaust. I'll make custom PS lines and oil cooler lines, I've done that before.

My main concern is any system that differs between diesel and gas, like the fuel or the ignition. It's uncharted territory so if anyone here has BTDT or knows the answers, I'd appreciate the help.

I'm going to a wrecking yard tomorrow just to look at a 280E and study it, hopefully to become more educated in how it differs from my 300TD, to start learning what I need to change.

Thanks!

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

the fuel economy's of the V8's used in the 400E+E420's are very close the straight 6's....but yes it would be more work.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

... you can find a 280 in a yard? it's likely the rarest vehicle in the mercedes lineup...
I've seen a few but not many...

even so... if you find one, best to bring the entire car over for the swap, then you'd need nothing else for the build.
I suppose you are planning to do away with the rear suspension?

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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 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Considering you live in california.....how are you going to go through emissions with a gas powered diesel?

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

EASY.... there are none. That's why a lot of diesel Volvos got swapped to chevy V8s... no emissions check.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

My buddy has a coversion available has a 380 V -8 , had to have a special exhaust manifold built so the v8 would clear power steering box, and regeared , he saved everything after someone ran a red light and centerpunched and totaled his car, that thing ran awsome, torquey , but i dont know what kind of mileage he was getting

I don't want to use the M119 engine (400E, E420, 500SL, etc). My best friend had one for a few months, and even though we're both die-hard MB fans, we cursed that engine. It's soooo expensive to maintain. And I've read scary things about the timing chain.

I am considering buying a 280E as a parts car to make the conversion easy. But buying the parts from the wrecking yard, though more expensive in the long run, would save me a parking space and ticking off my neighbors. I see one every couple of months at the yards.

I want to keep the rear suspension if I can. If I use the M103, I will utilize the tandem pump from a 300TE. If I use an M117 I'll utilize a 560SEL head and hydraulic pump. If I use any other engine, then I'll convert the rear to plain shocks.

nulu, if you can find out about that 380SEL swap and let me know, that would be great. I did think about that smaller V8, and the fuel economy wouldn't be ideal but the power would be fun and the simplicity of a finished kit would make it worth it. Where are you (and he) located?

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

Were in los angeles, hes out of town at this moment, but ill find out how much he wants later this week

Cool, thanks. LA isn't too far, I could make a weekend trip down with a truck.

Also ask him how much for the kit without the engine. Then I could buy an engine locally and not have to drive down.

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

Ill try and get him to sell , especially because he wants to store it in my garage,im already getting ready to start my c36 motor in my wagon, i have all the parts, brand new mercedes 104 block, diesel crank,complete c280-104 engine, extra 104 head and perfectly running 104 engine,and now thinking of a turbo

That's an awesome project, and it sounds like you're well prepared, haha. So the C36 engine was an M104 3.2 with the crank out of a 350SDL, or something like that, right? I love it when you can put car parts together like legos.

I always thought that with an M103, I would go standalone engine management with EFI to make it really a simple and clean install, and put on a turbo when I had the time again. If I don't get this V8 kit, that's what I'll probably end up doing. Are you using standalone engine management with the turbo M104?

In the meantime, just to keep the thread going, I've been thinking about mods to the fuel delivery system. I think everything between the tank and the engine will need to change, except for the long metal lines running under the car, which I might have to modify. I'll need an electric fuel pump and filter at/near the tank, and I am pretty sure I'll need all the fuel return junk most people ignore, like the charcoal canister, from a gasoline car. It doesn't have to be a 280E but that would be easier.

The gears are still turning...

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

Will go standalone injection, havent decided which one yet, as soon as crank is cut to c36 specs ill start the matching of componants