Weber/Stacks linkage expertise needed
 

Hey All,

Does anyone know of any shops/people in New England (preferably close to the Boston area) that are really good with tweaking/troubleshooting/fine-tuning linkages on Weber and/or stack injection? My dad has a stack injection on his 63 replica that we cannot get to run right, something is way off with the linkage. For the past few years we've been messing with it trying to get it straightened out...but haven't had any luck. The drivers side TB's are the one's directly connected to the bellcrank...passenger side is driven by a cross-link to the drivers side. I can get drivers side and passenger side synced up (using a syncrometer) at idle without any issue. But, once you start giving it throttle...the drivers side opens up way, way faster than the passenger side butterflies. There isn't any slop or play in the linkage, it's all tight...but just off idle the drivers side TB's start pulling about 3 times the amount of air the passenger side TB's are. So what you end up with is one side (passenger side) running pig rich...and it bogs, coughs, spits, crackles etc... It's almost as if where the linkage connects to the passenger side TB's is further down the throttle arm from the fulcrum than on the drivers side...so the drivers open faster, passenger side opens slower. But that's not the case, I've measured...and they are the same.

Pics are at the below link so you can see what I'm talking about re: the linkage:

P5260414.jpg Photo by pballent | Photobucket

Thank you very much, -Dave

First of all the levers that attach to the right and left banks need to be the exact same length from attaching hole to linkage hole to maintain proper geometry during operation. If this dimension is not the same one bank will open or close before the other bank causing the engine to stumble during acceleration.

Let's plan a date.
We can do this in Southern NH.
Karl is a master with Webers.
Linkage easy, get it from Inglese or John at Compclassics.
We can set you up "Free"
All part of the club.

FREE!

Also, we have done this before. Most shops will experiment on you.
Yes free.....

The problem you have is the crossbar linkage.

It will never work like that, even though Redline markets it.

The carbs or throttle bodies need to have the SAME throttle arms and they need to be independently operated from a centrally located bellcrank.

Draw your linkage on paper as viewed from the front of the car.

You can see how the drivers side will open more rapidly early in the throttle cycle.

It is because of the smaller angle between the drivers arm and the crossbar compared to the passengers side.

I would also add a vacuum reservoir tapped into each runner, to even out the manifold pulses at low engine speed.

Your map sensor then hooks up to this reservoir.

Gary