Convert from carb to FI? - PeachParts Mercedes-Benz Forum

snewpy · #1 01-22-2007, 04:10 PM

For anyone who hasn't been following my story, I have a '71 250c with the wrong motor installed. I plan to replace the 2.3L with a 2.8L engine I just found (and purchased).

The problem:

the 2.8L is fuel injected!

I am now faced with two possible options.
1. Convert the car to fuel injection. I assume this will require changing the fuel pump and adding a return line. Anything else?
2. Convert the engine to carburation. I am hoping the 2.3L head will fit the 2.8L block.

Any advice would be greatly appreciated and thanks to those who have already helped me.
Darren

300SDog · #2 01-22-2007, 05:32 PM

The sharpies here will want to know the year and series of your engine. MB deployed the inline 6cyl 280 in every body style they built for more than 12 yrs. And later version 280's aint nothin like the earlier ones.

(Edited post: to avoid confusion w/twincam models

snewpy · #3 01-22-2007, 05:47 PM

Sorry, I didn't give enough info.
The car is a '69 280SE and the motor is a SOHC M130 (130.980)
The motor in my car now is 180.954 and is supposed to be a 130.923

Complicated, I know.

Mark DiSilvestro · #4 01-22-2007, 06:09 PM

In the early '70s, an W114 250 FI model car WAS availible as the 250CE, with an electronic FI that would bolt right into your coupe. Problem is - that setup wasn't sold in the US.

The 280SE engine used in the W108 and W111 S-class sedans, coupes and convertibles from '68 - '72, is the one commonly found in the US. Those had a different engine block than the carb models, with a mechanical fuel-injection unit driven off the timing chain, and the distributor mounted at the FRONT of the engine block. The 280SE engine fits the longer engine compartment of the S-class cars, but it's distributor may not clear the radiator in the shorter engine comartment of your W114 coupe.
There may also be clearance issues with the 280SE engine's large intake manifold, and of course, the hassle of fabricating SE exhaust header pipes to fit your W114 system, plus adding a low-pressure/high-volume electric fuel pump,
but the biggest problem as I see it is the distributor location, which is dictated by the design of the engine block, not the head.

Happy Motoring, Mark

Mark DiSilvestro · #5 01-22-2007, 06:22 PM

Quote:

Originally Posted by snewpy

Sorry, I didn't give enough info.
The car is a '69 280SE and the motor is a SOHC M130 (130.980)
The motor in my car now is 180.954 and is supposed to be a 130.923

Complicated, I know.

But you said your CAR is a '71 250C. Do you mean the replacement MOTOR is from a '69 280SE?

Happy Motoring, Mark

snewpy · #6 01-22-2007, 09:08 PM

Yeah, the motor I just bought (but haven't picked up) is from a '69 280SE and looks very similar to what's currently in my car (I think the same distibutor position) except it has fuel injection an a different shaped valve cover (wavey along the side instead of straight). The exhaust also looks the same. Again, the motor currently in my car ('71 250c) is a '68 2.3L and was recently installed to replace the original blown 2.8L with dual carbs. It is no good because the crank is not balanced correctly for my flywheel.

alabbasi · #7 01-23-2007, 12:21 AM

This is a tough thread to follow! The W115 had fuel injected coupes (250CE and 280CE) and a Fuel injected sedan (280E) there was never a 250E.

Is the engine that is currently in the car a 2.3 four or 2.3 six? The W114's came with both. I remember talking to David Poole about a 280C to 280CE conversion using a K-Jetronic motor. He told me that he performed this sort of conversion and it required some cutting of the body (so be prepared).

If you can find a Euro 280E engine, this car will run like a bat out of hell. My 250CE was plenty fast enough.

snewpy · #8 01-23-2007, 12:30 AM

The motor in my car is a 2.3L I6. See my other threads for more info
engine balance question
difference between 130.920 and 130.923

It's confusing for me too! Mercedes made so many engine engines and car models back then. Nothing seems compatible and I'm getting frustrated.
Not to dispute the bad news that the motor I just bought bought won't fit, but does anyone else have any experience with this situation?

alabbasi · #9 01-23-2007, 12:32 AM

you can make anything fit ... all it takes is money. I suggest you look for a 250C engine if you require no mods. Else throw a Chevy 350 engine in and give the car some seriously fast legs.

OldMercs · #10 01-23-2007, 12:33 AM

I thought there was a 250CE with the M130 engine and EFI rather than mechanical injection? The only pecularity I recall about the US 250s is that they came with 2.8s rather than 2.5s as the euro-spec cars did. BTW, where are you? I was just looking at a 250C in a wrecking yard with a carbed M130 intact.

alabbasi · #11 01-23-2007, 12:34 AM

The 250CE came with an M114 and Bosch D-jetronic EFI.

Mark DiSilvestro · #12 01-23-2007, 08:26 AM

Quote:

Originally Posted by alabbasi

The 250CE came with an M114 and Bosch D-jetronic EFI.

The 250CE wasn't sold in the US, so it would be difficult to find one of those engines here, and it's probably not so easy to find one in Europe anymore.

As I understand the situation -

Snewpy has a '71 250C, which had a blown M130 2.8 carb engine. The PO replaced the blown M130 engine with an M180 230 2.3 engine. The M180 is unbalanced because the PO installed the M180 2.3 with the 2.8 flywheel!

Snewpy got an M130 280SE engine to replace the unbalanced M180, which might not easily fit because of the SE engine's front-mounted distributor.

Happy Motoring, Mark

snewpy · #13 01-23-2007, 08:39 AM

Quote:

Originally Posted by OldMercs

BTW, where are you? I was just looking at a 250C in a wrecking yard with a carbed M130 intact.

I'm in Canada on Vancouver Island.

OldMercs · #14 01-23-2007, 12:51 PM

Canada huh...so then Santa Paula, California would be a bit out of the way. Obviously a carbed 2.8 from a W114 would be the ideal engine for your situation, second best would be a either a carbed 2.5 or 2.8 out of a W108. I think it's hilarious that Mercedes made an entirely different block for the (mechanically) injected cars, too bad for your needs though. It's probably not impossible to convert your injected 2.8 to L-jet off a BMW or Datsun, but then there's the injector pump just hanging out. Mark seems to know his stuff, and I trust his say so more than the error-ridden Mercedes Buyers Guide that I've been getting a lot of info from. So Mark, are you saying if one ever ran across a D-jet M130 it would have to be euro-spec in origin?

cth350 · #15 01-23-2007, 12:51 PM

You can put an M130E motor into a W114 car. You will need to transfer a few relays and other bits of wiring from the donor car. Also, you will need to replace the small fuel line under the car with a larger one. Lastly, you need to mount a fuel pump.

Then there's the exhaust and the transmission. The engine pipes are different between the FI and carb'd straight 6 cars. Also, the transmission valve body and govenor are different. You'll want the transmission that came with the motor. If you car has a four-speed, don't worry about the transmission, that will work as-is.

-CTH