Tech Request: Multi-carb Linkages

well thats the idea. to buy somthing and bolt it on when you can built it or even redesign it seems like a sin

 

Sinister Custom, does the support bar in your setup have bearings or bushings in it?

 

my only concern about the chain and sprocket system is preventing anything from jamming it and sticking the throttle at wide open. i'm not purposely looking to bad mouth it. great thinking outside the box. i'm only thinking to way back as a kid and the old stick in the bicycle spoke trick.

 

you have to look at it closely. The center carb is not connected to the other carbs. The throttle cable is the only part connected to the center carb. with a longer bolt extension. The center carb operates by it's self until it opens to the point that the extension hits the finger that points down from the 1 to 3 link. With the 1-3 link connected closer to the butterfly shaft, the end carbs will open quicker than the center carb. and all reach WOT at the same time. You can see the large radius on the front of the finger to give it a smooth action. The extension has a piece of tubing over it to act as a roller when it makes contact with the finger on the 1-3 link.

It took me a minute to figure it out but people usually do things for a reason. Once it made sense to me I had to take a picture just for the reason for this post. I love the out of the box thinking.

 

ya i was hoping that the simplicity and such small scale would avoid any binding. like i mentioned the middle sprocket may need to be alittle larger to work as a tensioner and also may be a quickiner making the secondarys to open faster. by the time im done i will have the sprockets copper plated and probly a more fancy plating on the chain. all coinciding with the rest of my engine bay

 

Neither......only the two extended throttle shafts (which are brass) actually pivot in the shaft, which is aluminum. The support bar slides over the collars of the driver side carbs......which I cross drilled and tapped for set screws, which makes the bar very stable. This way, only two throttle shafts are spinning in the bar = less wear and tuning issues. A little drop of machine oil every once in awhile keeps everything working smooth.
Also, the extended throttle shafts I got have two set screws to hold 'em to the carb shaft....which if they're not tightened down evenly, will wobble at the end. The bar greatly stabilizes them.

Here's a few better pics....

 

our 235 tripple carb set up with carter w1 carbs and offy linkage.

 

We make our own linkage regardless of the number or type of multiple carbs.

It isn't difficult.

The biggest issue that many will experience is the failure to understand what the system is doing. Take a look at a FACTORY tripower on any GM car that used one. Pay particular attention to the rod connecting the front and rear carbs. One of the arms will have a round hole for the rod, THE OTHER ARM WILL HAVE A HORIZONTALLY SLOTTED HOLE! Which is front, and which is rear depends on the model and year, but most had the round hole in the rear (it doesn't matter).

The purpose of the horizontal slot is to allow for the coefficient of linear expansion. The front to rear rod should be adjusted (bent) such that it is in the center of the slot with a cool engine and both front and rear carbs closed.

Failure to compensate for expansion WILL cause one or the other of the end carbs to be cracked open, thus fouling the idle.

Jon.