Weber carb conversion (starting a new thread) - PeachParts Mercedes-Benz Forum

dmtinker · #1 10-14-2007, 12:47 AM

I wound up hijacking someone else's thread so I figured I'd start a new one.

I bought the Weber dual carb conversion kit for my 1967 250S and am in the process of installing it. The directions are detailed but don't have any pictures. This is a problem because the reference things that a lot of people may not be familiar with and could use a reference. Does anyone know what a "cheese head screw" is? I didn't. Also, the throttle linkage works in a very different manner than the Zenith carbs I was replacing. Also, being my first 250, I was not sure which line was the feed and which was the return for the fuel. I figured it out, assuming the feed comes from the fuel pump.

Anyway, I'm down to what I hope is my last problem. The directions call for the two short linkages to be set to 1 3/8 and for the long linkages (between carbs and to the activation lever) to 5 inches. The problem is that neither of these measurements are long enough. I think the long linkages are at lease 2 inches short. So, either they sent he wrong linkage or the kit is universal and I have to buy/fabricate my own linkage.

Has anyone else run into this?

If anyone has the weber setup, could you measure the length of each linkage I would appreciate it. It would REALLY help me out.

nhdoc · #2 10-14-2007, 08:13 AM

Since each application is different you might want to call JAM and ask the specifics about the linkage lengths. It may be that the spacing of your intake manifold is different than what their design calls for or they sent you the wrong kit. What is the approximate spacing (center to center) of your intake manifold flanges where the carbs bolt to?

As for terms you are unfamiliar with, such as cheese head screw you can always try posting here or googling the term. In this case, if you google cheese head screw you will find a detailed explaination on the very first link. Wiki is a good source too, their site defines it as: "cheese head: disc with cylindrical outer edge, height approximately half the head diameter."

And, yes, the fuel feed line comes from the pump and the return line goes straight back to the tank. I would highly recommend using a tubing cutter rather than a hacksaw to cut the lines if you have not done it already. I hate the idea of sawing on the end of a steel line full of fuel and gas vapor. One small spark and it could be bye-bye. A tubing cutter will also provide you with a much better cut than a saw can. You can buy a cheapo one in the plumbing dept of any home center.

dmtinker · #3 10-14-2007, 01:50 PM

I didn't get my kit from JAM but looked at some instructions that came with a kit from them. The JAM kit has pictures that would have helped me a lot. In stead of a 5 inch space, I think the distance between my carbs is 7.5. I looked another picture that someone here had on a similar car. Based on that and knowing what the linkages SHOULD look like, I think I am right. I'll see if I can find ball and cap linkage rods locally and eyeball it. I should be ok if the kit does come precalibrated as described or at least close.

nhdoc · #4 10-14-2007, 02:14 PM

Quote:

Originally Posted by dmtinker

I didn't get my kit from JAM but looked at some instructions that came with a kit from them. The JAM kit has pictures that would have helped me a lot. In stead of a 5 inch space, I think the distance between my carbs is 7.5. I looked another picture that someone here had on a similar car. Based on that and knowing what the linkages SHOULD look like, I think I am right. I'll see if I can find ball and cap linkage rods locally and eyeball it. I should be ok if the kit does come precalibrated as described or at least close.

That might explain it...there are some kits which are really not very well thought out...you might have one of them. The JAM kit is the most expensive but everyone I know who has used it has said it has been pretty much plug and play. You ought to be able to find some parts to make yours work or you could contact the people who made it to see if they have a longer one. Is your rod the kind with threaded ends? You can just buy a piece of threaded rod stock at home depot and cut it to length assuming it is an SAE thread and not metic. If metric you could buy a die for the thread and cut some on some rod stock too or look for metric rod stock at a machine supply company.

dmtinker · #5 10-14-2007, 02:46 PM

I bought it new from Alamomotorsports.com because it was $840 and it was a Weber kit; the same model JAM sells so I figured they'd be the same. Mine has plastic cups with threaded ends. The ends are reverse threaded (right hand on one side left hand on the other. Also, they only extend out to about 6 inches which is why I think that they may have put in the wrong parts. I can't imagine that each application would vary THAT much.
Weber is common enough that I'm hoping to find there parts in a speed shop. I do know they sell the rods aftermarket in various lengths. If you do happen to get under your hood, I would be curious as to what your lengths measure. But it is no big deal if you don't.

nhdoc · #6 10-14-2007, 02:53 PM

Quote:

Originally Posted by dmtinker

I bought it new from Alamomotorsports.com because it was $840 and it was a Weber kit; the same model JAM sells so I figured they'd be the same. Mine has plastic cups with threaded ends. The ends are reverse threaded (right hand on one side left hand on the other. Also, they only extend out to about 6 inches which is why I think that they may have put in the wrong parts. I can't imagine that each application would vary THAT much.
Weber is common enough that I'm hoping to find there parts in a speed shop. I do know they sell the rods aftermarket in various lengths. If you do happen to get under your hood, I would be curious as to what your lengths measure. But it is no big deal if you don't.

My car is stored off-site but I will look tomorrow when there and measure it for you...

dmtinker · #7 10-14-2007, 04:04 PM

You're a peach...thanks

nhdoc · #8 10-15-2007, 12:29 PM

I just measured and the distance between the carbs on my '64 220Sb is 7 3/8". That's consistent with your measurement which means the kit you got has the wrong part in it...I'd go back to the people who made it and get them to replace it.

dmtinker · #9 10-15-2007, 02:45 PM

Thanks, I thought I was going crazy. Already being leery of this job, since I'm not that familiar with carburetion, I was at my wit's end. I'll call them. I'm glad my measurements were correct.

dmtinker · #10 10-15-2007, 03:35 PM

I called Redline and they were very nice, extremely unhelpful. They were basically telling me that the parts they sent were for my application and they would be willing to fax a picture to make sure I knew how its should look. I told them that
1. they should have already had a picture in the box
2. I have already downloaded the picture (diagram) they were going to send
3. I also have a picture of it installed already.
4. I've had other people measure their application on the same car and it matches what I had.
5. They're still wrong.

I was then told the kits are packet in England and they would need to have me send back the kit and they would send me another. I told them to lick me. (not really but I was not happy). I finally got them to send me out the linkages I need but I'm not confident.

Does anyone know where I can buy this type of linkage online?

nhdoc · #11 10-15-2007, 04:06 PM

Quote:

Originally Posted by dmtinker

I called Redline and they were very nice, extremely unhelpful. They were basically telling me that the parts they sent were for my application and they would be willing to fax a picture to make sure I knew how its should look. I told them that
1. they should have already had a picture in the box
2. I have already downloaded the picture (diagram) they were going to send
3. I also have a picture of it installed already.
4. I've had other people measure their application on the same car and it matches what I had.
5. They're still wrong.

I was then told the kits are packet in England and they would need to have me send back the kit and they would send me another. I told them to lick me. (not really but I was not happy). I finally got them to send me out the linkages I need but I'm not confident.

Does anyone know where I can buy this type of linkage online?

Try calling JAM, they sell pieces of the kits too...I bought some gaskets from them and their prices were reasonable.

dmtinker · #12 10-15-2007, 04:13 PM

Actually, I got a call from the Redline sales rep. for Alamomotorsports.com and he's working to fix the problem. I will say that both companies are working hard to fix my problem.

nhdoc · #13 10-15-2007, 04:55 PM

Quote:

Originally Posted by dmtinker

Actually, I got a call from the Redline sales rep. for Alamomotorsports.com and he's working to fix the problem. I will say that both companies are working hard to fix my problem.

Good to hear...let us know how it finally gets resolved.

dmtinker · #14 10-18-2007, 10:49 PM

I just wanted to let everyone know I've got the carbs on and started it briefly today. I have to loosen up the carbs and re-seat them so that the air filter sits ok.

I found that the problem was an ambiguity in the instructions. I was supposed to retain some of the old linkage but it said that in an area of the directions that didn't apply to me. Also, I was supposed to keep one link and retain another which seems odd to me. They also put in two link rods in the kit but I'm only supposed to use one. Needless to say it was a bit confusing.

Weber had sent me some know rods but I think I'm going to replace them with the old linkage. The ones they sent with the kit are plastic and the get worn quickly when they are taken off and on frequently.

Anyway, it seems ok so far. I have to do some adjustments but I think it's going to be ok.

dmtinker · #15 10-19-2007, 12:33 PM

I changed the linkage this morning and put on the two original rods from the zenith. The car ran well. I'm ready to button it up and send it off for inspection.

One question though, I'm thinking of putting on the Weber air filters but am wondering what to do with the vent that is on top of the valve cover that goes to the old air cleaner? Can I block it off?