PeachParts Mercedes-Benz Forum - weber conversion results-long post

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If I recall correctly, the early North American M110 (73 to 76) had only vacuum retard. Look around for a European or 77 and later US distributor.

Some cars actually had a vac advance and vac retard, my 84 bmw did. I think the mbs were set up differently though, as noted above.

The bmw would never run properly with correct power til I modified the distributor to give pre emission controls performance.

Tom W

Spring has finally arrived here in Canada, time to put the car back on the road.

I installed a fuel pressure regulator in january (fuel pressure is now as required by weber redline) and after speaking with a weber redline representative I had the timing set to 10 degrees BTDC and now it finally runs well!!!

I'm not crazy about the gas pedal feel (not progressive, almost like an on-off switch) but I think I'll be able to fix that.

Thank you all for your input!

Sometimes there is a very fine adjustment of the throttle plate that covers or uncovers ports which direct air to different places. So the fine adjustment might need another look. There should be complete instructions on it. Off throttle response is also related to the accelerator pump.

Tom W

the crane and pertronix setup is good for distributors that are not worn out.
if the car still feels sluggish with them, watch out for a 123 ignition.
maybe there are dealers in canada too: http://www.123ignition.nl/id/25.html

Quote:

Originally Posted by Housecrew (Post 1821123)

Is this just like a Mallory distributor? The info on the web-page is rather vague about what the triggering system is. I'll read the whole page when I get time.
If it's like a Mallory this may be the ticket for a more modern style ignition w/o the need to go crank-fire style.

Anyone used one of the 123 systems before?

This is a very old thread and also my first time one this forum (Hi everyone!) - but I thought I might still get in touch with someone who knows this.

I am about to go through the same Weber (K248 kit) conversion on my W116 280S after I finally caved in (my Solex is badly bent from previous owner bolting it on with too much torque and a complete rebuild didn't help either).

My question is:
There is a thick insulator with glued-on gaskets on the intake manifold onto which the carburetor mounts (

this one here). Is that still required with the weber kit? Or does the kit's adapter plate bolt directly onto the intake manifold?

Thanks!
Agav

Quote:

Originally Posted by bluebenz (Post 1677949)

Sorry for the long post!!! This great forum has helped me a lot in the past, and hopefully some of you can give me pointers so I can enjoy my car again! I spent a lot of money on a weber conversion and so far the results are not as good as expected, although it is an improvement!

I fell in love with the MB 114 when I was a kid, and I bought one off ebay last fall. A 1973 280C with 90000 miles. Great looking car and I enjoy it a lot although the past months have been frustrating at times!

When I got the car last year, I had a tune-up done: new NGK spark plugs, new plug wires, distributor cap, rotor and points (no condenser, couldn't find one), new air and fuel filters, oil and filter change, transmission oil and filter changed. I also replaced the battery, new battery cables. The previous owner had recently changed most belts and hoses, fuel pump and rebuilt the solex carb.

The car ran extremely well for 8 months, then some problems started: Very hard to start when cold, rough idle, stalling, sometimes hard to start when warm. First step was to remove a leaky fuel return valve (could not find a new one so just removed it) and that seemed to help a lot, at least temporarily. I then installed a crane XR-700 pointless ignition system with a new crane coil, and thought the problems were solved for good.

Unfortunately in september the cold start problem got worse and the stalling at intersections made me nervous. The solex carb was leaking, float was stuck, and after reading a lot on this forum I decided to get a new redline weber 38 dges conversion kit. Got the new carb installed by my trusted mechanic. Removed the egr and some other emission stuff at the same time. Timing was set after carb installation.

Now the car starts well when cold or warm, the idle is smooth, and it doesn't stall anymore. Car is powerful and smooth. The only problem is an annoying flat spot or hesitation on take off (the car does not move for 1-2 seconds when you press on the gas and then it goes) and a shorter hesitation when accelerating hard from a cruising speed. The only way to avoid this initial hesitation is to accelerate very slowly from 0 to 10 mph and then you're OK.

The weber web site says the fuel pressure should be 1.5 to 3.5, mine is 4.5 but I dont think it is causing my problem. I suppose I could install a pressure regulator but dont want to spend more money if it isn't necessary.

Hopefully we will be able to fine tune the carb (accelerator pump adjustment maybe?-could not find out how to adjust it on the weber web site) and enjoy this car again! I was wondering if anyone who had done this conversion had similar problems?

Thanks for your input!!!

hi , sounds very fimiliar, what ignition timing are you running, initial timing With out vacuum, I had a lot of problems in the start too, I went With the holley from jam and its a good set up With fuel squirters .I found out in the end that I had to increase my initial timing to about 15 degs, made a huge amount of difference.I also disconnected the vacuum advance(dont use it any more)i HAVE ALSO READ SOME PLACE THAT THE WEBERS DONT HAVE SQUIRTERS , which in turn causes a flat spot on initial start. Try advancing Your timing to about 12-17 deg and give that a og first..in there is a sweet spot. good luck