W108 280SE conversion to carb - PeachParts Mercedes-Benz Forum

noah · #1 08-06-2007, 11:09 PM

Would it be possible to put a sidedraft weber on the end of the existing MFI intake manifold and just do away with the fuel injection?

t walgamuth · #2 08-06-2007, 11:47 PM

Yes, I would say. I probably would try pretty hard to fix the fi first though.

Tom W

cth350 · #3 08-08-2007, 03:50 PM

I know of a 250se with carbs in Argentina.
You really don't want to do that. Buying a used motor is a cheaper, more straight-forward alternative.

-CTH

noah · #4 08-08-2007, 09:45 PM

I guess I just had the thought and posted the question without really thinking it through. Are there any good sites or books that explain this fuel injection system in detail or at least give good tune up advice?

Chas H · #5 08-09-2007, 01:06 AM

There are many good books on fuel injection. Bosch, of all companies, publishes a good one. Most of the good stuff in copyrighted so you won't find much on a website.
Back to your original question, you might consider fitting a carburettor manifold and adding the carb(s) of your choice.

Mark DiSilvestro · #6 08-09-2007, 11:43 AM

Quote:

Originally Posted by Chas H

There are many good books on fuel injection. Bosch, of all companies, publishes a good one. Most of the good stuff in copyrighted so you won't find much on a website.
Back to your original question, you might consider fitting a carburettor manifold and adding the carb(s) of your choice.

Though keeping the mechanical injection pump spinning without fuel may cause problems, and there's no practical way to eliminate the pump as it drives off the timing chain.

It might be more do-able if your W108 was one of the EFI V8 models. There was a 450SLC on eBay a few years ago with a 4V carb grafted onto the intake manifold.

Happy Motoring, Mark

Chas H · #7 08-09-2007, 02:48 PM

Quote:

Originally Posted by Mark DiSilvestro

Though keeping the mechanical injection pump spinning without fuel may cause problems, and there's no practical way to eliminate the pump as it drives off the timing chain..
Happy Motoring, Mark

The pump can be removed and a block-off plate applied to the hole. The drive for the pump does not rely on it for support.

snewpy · #8 08-10-2007, 11:53 AM

Quote:

Originally Posted by Chas H

The pump can be removed and a block-off plate applied to the hole. The drive for the pump does not rely on it for support.

Really? I thought this wasn't possible. I want to do this on the FI M130 motor I got from a '69 280 SE to put in my '71 250C. I want to change the manifolds over to the dual zeniths I currently have in the car.
Have you done this? Do you have any other advice or pictures that might help me out? Should I just leave the injectors in the head or put plugs in the holes?

Mark DiSilvestro · #9 08-10-2007, 12:37 PM

Installing plugs in place of the injectors would certainly make it look neater, but before you yank that 250C motor, keep in mind the 280SE distributor is in front of the block, and space is alot tighter between engine and radiator on the 250C, so measure carefully first.

Happy Motoring, Mark

snewpy · #10 08-10-2007, 01:43 PM

I've checked the distibutor to rad clearance and although it's close, I should be OK. As I see it, I also need to change the motor mounts, add an electric fuel pump and remove the external oil lines (among many other things). Anything else major that I may be over-looking? (sorry to the original poster for hijacking this thread)

Chas H · #11 08-10-2007, 02:23 PM

Quote:

Originally Posted by snewpy

Really? I thought this wasn't possible. I want to do this on the FI M130 motor I got from a '69 280 SE to put in my '71 250C. I want to change the manifolds over to the dual zeniths I currently have in the car.
Have you done this? Do you have any other advice or pictures that might help me out? Should I just leave the injectors in the head or put plugs in the holes?

I've changed the sprockets and drive gears for the pump. Also driven off the pump drive are the distributor and the oil pump. I have not converted an injected car to carbs, but I have contemplated doing so. I made a lamp from the drive gears and will try to get a photo later
The injectors in the 130 engine are in the manifold. If you swap in a carb manifold the injectors leave with the injection manifold.

Chas H · #12 08-10-2007, 04:35 PM

Thanks for the correction. It's been a long time since I pulled the head on any Benz.

bwostosh · #13 08-10-2007, 04:44 PM

I've see it done on a M127 motor,
I can sell you an entire W108 with MFI cheaper than those webers.

Alex Rozzi · #14 08-14-2007, 01:00 AM

Well, friends, I'm glad to be talking about Benzes again, thanks Charly for the Link, it's a great site.

About thread:
it's possible, my 250 has them, but as Charles says, it's not an easy Job, but If you are bored, I can collect pics and info for you.

take care amigos!!!

cth350 · #15 08-15-2007, 11:14 PM

Alex, welcome!

Gent's, that car in Agentina I mentioned earlier is Alex's. Though I believe he got the car that way.

-CTH