Weber linkage
 

I am begining the journey towards 48 IDA Weber installation on my 289. My manifold has the carbs facing each other with the fuel inlets on the outside.
I have heard conflicting information regarding which type of linkage is better. Some use the center bellcrank (relocated pivot) with the pairs on the banks connected together and some have used the center rod with connecting links to each individual carb; and some use a bellcrank with side pull. Since mine uses a cable to activate the current Holley I am inclined to incorporate this into the Webers installation as well. I have searched the site for pictures of linkage and found a few, but details are difficult to see. I would like to see some clear overhead pictures of various installs. Would some of you with Webers mind sharing your success?

Thanks

I used the center pull rather than the side push. I fabracted a plate between the carbs and used ERA linkage. I had to lengthen the rear arm and design a new center linkage. The bell crank worked well set up higher on a post, less angle. I have not taken any pictures yet but when I get some I willl post or email them to you. I am still playing with the jets, idle and main to acheive perfection:confused: . Just fun. Car runs great with them though. Just a thought, Maybe 44's might have been better on a 289/302 than the 48's? They are alot of carb for a small everyday engine at low speed, not racing or high speed driving. imho and a thought.
Corky

Hi Rick
Weber linkage is always a big deal. It depends of your specific requirements. I have modified an Inglese system to adapt it at my own configuration. I prefer to use a rod linkage than a cable. If you use a cable, you have a linear trottle opening (50% of pedal travel made 50% of trottle openning). If you use a rod linkage you can obtain a more progressive trottle openning at the beginning (50% of pedal travel can made only 25% of trottle openning). Obviously with a 100% of pedal travel you have a full trottle openning. This setting can be done according to the 90° cross lever angle position. This point is interesting to go smoothly out from a corner due to the higher trottle pedale sensitivity ;)

When I was at Carlisle in May, The dark blue FIA car had a new motor with Webers and had a center linkage set up. Maybe some one at ERA can shed som light on the set up and what parts are needed.

Here is my setup Rick,

http://www.clubcobra.com/photopost/d...m/DSC00051.JPG

http://www.clubcobra.com/photopost/d...m/DSC00050.JPG

The reversing plates do make linkage setup much easier.

Scott S

If you are looking for a good source for linkage, try www.dalewilch.com. Heim joint rod ends www.racingrodends.com Cobra Jeff has some nice pictures of his center linkage set up.

http://kinsler.com/hand31.html
and look under linkage

Scott S, where did you purchase your linkage parts?

This is very very close to the original FIA linkage. Sorry for the blurry image.

http://www.clubcobra.com/photopost/d...m/DSCN1818.JPG

I purchased most of them here,

http://www.piercemanifolds.com/linkage.htm

Scott S

Without major change I am relegated to a cable actuation, I have decided to give this a try, it seemed the easiest. Now to balance the pedal travel to the throttle opening.


[IMG]http://www.clubcobra.com/photopost/d...m/P7080169.JPG[/IMG]

[IMG]http://www.clubcobra.com/photopost/d...m/P7260228.JPG[/IMG]

Will this set up work using opposing carbs? I plan on using a center rod, using this linkage set up for the 2 center carbs and the 2 rear carbs. I tried to use 2 rods, linked to the center lever (see Kirkum picture above) but could not come up with a combination that opened the carbs equally. It would open the carbs evenly to about half throttle and there have about a 6 degree difference at 3/4 throttle.

It seems finding the right linkage set up is more of a PITA than jetting the carbs.

Home made Weber linkage

Check with Jim Inglese for advise and help. He is the best and got his experience with real Cobras. Can be found at http://www.jiminglese.com/index.html or (203) 623-0659.

http://i13.photobucket.com/albums/a2...02modified.jpg
http://i13.photobucket.com/albums/a2...05modified.jpg

Not Webers, but the idea is the same.

I'v been playing with mine over the years, trying to get it just right. I finally scrapped the original design, and made my own. But, here's what I learned. It is critical that all blades oepn exactly the same amount at exactly the same time. This is critical to smooth operation and power production. Even the slightest differance will affect performance. Before tuning the carbs, you have to get the balance exactly right from idle to WOT.

The central bell crank is on a pedestal, bolted to the boss in the manifold. I made the pedestal out of some 2" alum hex rod. Very stable, no flex at all.

The arms I made from 3/8" hex rod. I decided to make my own because I didn't have a local source for them. I didn't want to try one length, throw it away, and wait a week for the next size to arrive. I got it all done in 2 days. The only tools I had to buy was a left handed tap. So I'm sure I saved some money.

I use a throttle cable. It's easy to route, and no real fabrication involved. It doesn't look original, but I don't care about that. I had to make the cable bracket you can see in the second picture. Not a big deal. I made it out of some sheet metal I had lying around. Took some experimentation to get it where I wanted it.

I must have spent a week working on the linkage. But now it's perfect, works smooth, and the balance is perfect throughout the range. And, I made it myself.

Here is the set up on my small block FFR

This is the great thing about this site, great information guys......:3DSMILE:

Why did you use 2 bell cranks? One double arm, and one triple arm? Couldn't you accomplish the same thing with 1 triple?

You can, but the crossing links on one side may interfere with one another depending on how you set up the whole lot.

The setup above is from Inglese, very good piece of gear.

Weber Linkage
 

Rick,
The simplest linkage on the 289-302 Weber system with opposed-facing carburetors is one with a single crossbar connecting each bank. When viewed from the front of the engine, the crossbar sits on a diagonal.

In this arrangement, one bank of carburetors is operated by a lever facing up, and the other bank is operated by a lever facing down. This offers the correct geometry with opposite-rotating throttle shafts. Activation is via a bellcrank mounted on the outboard side of the the left rear carburetor, over the valve cover.

All the other linkage arrangements seen here will work, and I am not finding fault with anyone's layout. But smooth off-idle throttle response in traffic is extremely important, as is keeping all four carburetors synchronized. By using as few linkage pieces as possible, it's an easy task.

As you develop your linkage, keep in mind that you will need a simple way to synchronize each carburetor independent of the rest (you don't want ANYTHING to move except the throttle plates of the carburetor you are setting), and you will also want the ability to raise or lower the idle speed with one master idle speed screw that effects the entire system. With Webers, simplicity is your friend.

I hope this helps you.