Update on 280C Progress, question regarding air pump... (W114 M110) - Page 8 - PeachParts Mercedes-Benz Forum

Rahulio1989300E · #**106** 09-22-2010, 04:01 PM

Time to update a bit...

Above is the old fuel pump new to the new shiny one...

Close-up of the new fuel pump.

Close-up of the old fuel pump.

This is where the pump mates to the engine block, you can see the cam which touches a lever (looks like a rod) on the fuel pump to get it to start moving fuel from the tank to the carb.

The part in the center of the photo is strictly for emissions. One hose goes to the air pump (which is now gone from my car, two others connect to the stock air cleaner) I removed this device from the car, eliminated two vacuum lines that I had no idea what to do with as well.

Emissions device extracted.

Test fitting cleaned and painted pulleys...

The new fuel pump and old fuel pump were not the same in terms of size, this new pump does make contact with the power steering pump. I will need to keep an eye on this to make sure that the fuel pump does not get damaged from vibrations or movement from the contact of these two pumps.

The brass T shaped joint you see is what I used to replace the fuel overflow valve on the Solex. So, if the new Weber has enough fuel, the excess fuel will flow back into the tank.

I used a new Laso water pump to replace my old tired pump. When I test fitted the water pump pulley, the rear edge of it was making contact with the harmonic balancer, and if I tightened down the pulley onto the water pump, it basically locked the water pump in place... I had to add 4 washers to the back of the water pump pulley to act as spacers so that the pulley no longer made contact with the balancer.

Fitted new rubber sliders on the sides of the radiator before re-installation.

Rahulio1989300E · #**107** 09-22-2010, 04:04 PM

So since then I have changed the oil to a 10W-40, poured distilled water into the radiator and started the car... It runs rough but I am slowly figuring out how to tune the Weber, which is actually really simple.

There does seem to be a problem with my fan clutch as the fan has a bit of a wobble and noise to it. I think it may be due for a good used one or maybe I should just convert to an electric fan. The water pump pulley has no play to it and it appears to be spinning true, so I don't think my modification to the pulley went sour...

I hope to make a video of the engine running and will post it here soon.

As of now, the car starts and runs well in idle... but when I put the car in gear, and try to accelerate briskly, it stumbles and has hesitation and I even got it to stall once. If I am extremely slow with how much input I give the gas pedal, then the car is VERY SMOOTH, but in order to drive it on the street and such, I need to be able to have the car accelerate smoothly at at least a moderate rate.

I will keep trying to tune the Weber, but its there any advice? should I try to raise the idle speed?

Another note, I want to say a big
THANK YOU
to the forum members who have given me your advice and knowledge, this car would not even been running today if it was not for your help.

bluebenz · #**108** 09-22-2010, 09:07 PM

Quote:

Originally Posted by Rahulio1989300E

So since then I have changed the oil to a 10W-40, poured distilled water into the radiator and started the car... It runs rough but I am slowly figuring out how to tune the Weber, which is actually really simple.

There does seem to be a problem with my fan clutch as the fan has a bit of a wobble and noise to it. I think it may be due for a good used one or maybe I should just convert to an electric fan. The water pump pulley has no play to it and it appears to be spinning true, so I don't think my modification to the pulley went sour...

I hope to make a video of the engine running and will post it here soon.

As of now, the car starts and runs well in idle... but when I put the car in gear, and try to accelerate briskly, it stumbles and has hesitation and I even got it to stall once. If I am extremely slow with how much input I give the gas pedal, then the car is VERY SMOOTH, but in order to drive it on the street and such, I need to be able to have the car accelerate smoothly at at least a moderate rate.

I will keep trying to tune the Weber, but its there any advice? should I try to raise the idle speed?

Another note, I want to say a big
THANK YOU
to the forum members who have given me your advice and knowledge, this car would not even been running today if it was not for your help.

The hesitation, stumbling and stalling on acceleration is exactly what I experienced with the weber on my 73 280C! Advancing the timing did help a little bit but was never able to get it to run right!

Rahulio1989300E · #**109** 09-22-2010, 09:37 PM

Quote:

Originally Posted by bluebenz

The hesitation, stumbling and stalling on acceleration is exactly what I experienced with the weber on my 73 280C! Advancing the timing did help a little bit but was never able to get it to run right!

Okay, fair enough!

I do feel that I just don't have it dialed in right yet. I have tinkered with the Weber only a few times, not even sure if my vacuum lines are correct, etc. I guess what I am saying is that it is too early for me to blame the set-up!

I guess I will know by the end of tomorrow after hours of tinkering whether or not this Weber kit is pure junk or pure heaven or something in-between.

kraakevik · #**110** 09-23-2010, 09:38 AM

I finally installed a manual choke on the Weber 38DGES so I can enrichen the mixture when needed around town--this eliminated the stumbling/stalling at takeoff. I believe the Weber simply won't flow enough fuel at low speeds.

Tim Kraakevik
kraakevik@voyager.net
Four M110's

Rahulio1989300E · #**111** 09-26-2010, 03:18 PM

Today I finally had some time to mess with the Weber.
I turned the two mixture screws CCW about 1/8 of a turn and then did some acceleration tests from a standstill after the car was warmed up. It no longer stalled out after a moderate tap of the gas pedal. Then I went ahead and took it for a spin around a loop in my neighborhood.

I still found that I had to baby the gas pedal a bit if I wanted a smooth, gradual acceleration. If I pushed the pedal in a bit briskly, the car would bog for a moment, and then suddenly accelerate extremely quickly. This car is really fun the drive, even with worn sway bar bushings.

My next steps are to verify that the Weber is in fact getting the correct fuel pressure the 38DGAS calls for, which I believe is 2.5 to 3 lbs.
What I suspect is that the Weber is getting a bit too much fuel from the pump with it being directly connected. and when I press the gas pedal is it dumping excess fuel into the engine which causes it to bog down before it can eat it all and then stabilize with the steady flow that the Weber provides.
Just a theory... I think I am going to try to find a fuel pressure gauge that I can install in line after the fuel pump and fuel filter, right before the Weber.

Phew, there sure are going to be a lot of things installed along the fuel line that goes from the pump to the Weber... I already have a brass T fitting and a fuel filter... Now there may be 4 things!

Overall... PROGRESS IS BEING MADE, which is important...

Rahulio1989300E · #**112** 09-26-2010, 03:20 PM

Quote:

Originally Posted by kraakevik

I finally installed a manual choke on the Weber 38DGES so I can enrichen the mixture when needed around town--this eliminated the stumbling/stalling at takeoff. I believe the Weber simply won't flow enough fuel at low speeds.

Tim Kraakevik
kraakevik@voyager.net
Four M110's

Hey Tim, glad to hear you solved the problem... so I guess what you are saying is that the Weber created a lean condition upon takeoff and was not delivering enough fuel at takeoff...

If the manual choke fixed the problem, then maybe that is what I need to do... could you share which choke you got and how you routed it to the interior?

Thank You

mercmad6.3 · #**113** 09-26-2010, 04:52 PM

Bogging on take off is an excess fuel symptom. Backfiring through the carb on takeoff is too lean.
These carbs were originally on Ford 3 liter V6 engines and will produce plenty of air and fuel flow for a 2.8 liter mercedes engine.
I suggest you get your distributor 'recurved' to advance faster or obtain a euro pointless distributor and switch box from a W123 280 E or W126 280 SE. Both produce a 20-30,000 volt spark and are totally trouble free with a quick advance from idle.

kraakevik · #**114** 09-27-2010, 02:18 PM

Closing the butterfly solved the stumble/stalling problem.

I bought a $10 manual-choke kit from AutoZone, routed the small end through one of the many firewall apertures and mounted the push/pull knob on the plastic panel directly beneath the steering column.

Building the bracketry for the cable at the choke end took some ingenuity--expect to spend a couple of hours to get the cable travel consistent.

Tim Kraakevik
kraakevik@voyager.net
Four M110's

mercmad6.3 · #**115** 09-27-2010, 04:49 PM

By closing off the air flow,you aren't curing the problem,simply adapting to a bad situation .
Weber carbs are infinitely tuneable and I would think that opening the accelerator jet would allow get more fuel .

Rahulio1989300E · #**116** 12-15-2010, 02:55 PM

Well, its been some time since I have updated this thread. I have been busy with work, but I have had a few opportunities to work on the 280C here and there.

I have installed a Holley fuel pressure regulator with a gauge and some fittings from Home Depot. (Set to 2.5 PSI)

Here are some pictures of the unit:

I need to fabricate a metal bracket to make the install clean, but for now it is suspended off another hose in the engine bay, the idea is that it needs to be level with the float of the carb from the ground.

Good news is the car idles and accelerates extremely smoothly now! Has a much more gradual curve from idle to throttle, and much of that on/off switch feeling has been eliminated. One problem though is that I think the car is running too lean right now. I am getting a light to medium amount of grayish white smoke from the tail pipe, so I do need to keep up my tuning efforts to try to get to where I was where there was no visible white (lean) or black (rich) smoke. Though, there is a small fear in my mind that the head gasket might have somehow gone bad between now and my last tune... if that is the case...

I am going to see if I can find some time to further tune the car and get rid of the smoking... wish me luck!

alabbasi · #**117** 12-15-2010, 03:06 PM

You're pretty local. I have a CO analyzer. If you want to stop by sometime, we can stick it in the tail pipe and you can adjust the mixture accurately (assuming you have no catalytic converter).

Rahulio1989300E · #**118** 12-18-2010, 09:53 PM

Quote:

Originally Posted by alabbasi

You're pretty local. I have a CO analyzer. If you want to stop by sometime, we can stick it in the tail pipe and you can adjust the mixture accurately (assuming you have no catalytic converter).

Thanks for the offer alabbasi, the car is not registered or inspected so I can't drive it out anywhere besides my neighborhood for now. Going to try tuning further tomorrow and see what happens. If I can get the engine air/fuel dialed in, I am going to remove the seats seat and pull the carpets. The rear sections of the floor boards are rusted through, so I am going to use a cutting disk on an angle grinder and remove the cancer. My friend recommended a mobile welder for me to call and have him come weld in new panels for the floor. Then I am going to go nuts with POR-15 and move on to brakes and flex discs, etc...

alabbasi · #**119** 12-19-2010, 01:15 PM

No problem, if you're not aware, you can get a temporary tag from the tag office for 30 days. All they require for this is insurance on the car. You can then drive it for one month legally without inspection stickers or tags. It costs $25 for 30 days. I've used this in the past when trying to get my cars ready for inspections.