Tech Request: Multi-carb Linkages

There's always more ways than one to do something. I'd love to see all the ways (preferably with pics) that folks have linked up their carbs (in particular, 3x2s), no matter what carbs they're running.

Bring 'em on!

~Jason

 

I was just discussing this very thing today. Seems there should be a few basic formulas that would allow even a novice to put together a safe,working, progressive linkage. The aftermarket stuff is rudimentary at best and works so-so.

I'll be interested to see what is posted here.

GV

 

I put this together out of pieces I had

 

Good topic! Always interested in this topic since I'll be wrapping my head around 6 Holleys that will be progressively linked also.

 

Here's a couple of pics of my setup.....4 97's, progressive.

Also a pic of an Edelbrock crossram with 2x2 adaptors and 94's....I believe this is on a Canadian Hamber's car. Really cool.

 

here is how jonnycola did it: http://www.jalopyjournal.com/forum/showthread.php?t=225519

 

Formula?

For those who didn't read it:
The proportion of arm lengths determines how far the primaries can open before the secondaries open, but all must reach WOT at the same point no matter what. Typically, the progression varies from the primaries 1/3 to 2/3 open before the secondaries crack - and that means that the levers on the secondaries must be 1/3 × to 2/3 of the length of the levers on the primaries to do this.
A ratio of 1/3 primary carburetor(s) to 2/3 both carburetors may not be enough for a small engine and heavy car to cruise without using the secondaries, using 1/2 - 1/2 allows higher engine RPM on primaries only for better mileage.
The return spring should be at 90° to the primary arm at idle, and I suggest a second spring at 90° to the WOT position (but be careful that one does not pull the other over-center).
All levers should be as long as possible for best accuracy in adjustment, and should be roughly vertical at mid-range.
The levers from both primarys must be exactly the same length (between throttle shaft and heim joint), and operate at the same angle, the secondaries the same (although obviously different length and angle).
If they were solidly connected, all that would happen is that all 4 would open together, and stop when the secondaries reach full throttle.
The link between the primary and secondary slides freely until it reaches an adjustable stop. Adjust the individual levers first to the desired ratio: 1/3 - 2/3 means the secondary arm is 2/3 the length of the primary, etc. If you want 1/3 - 2/3, the block is at 1/3 of the link length, etc.
Test, using 1/3 as ratio of choice:
1. move the throttle slightly from idle stop
2. both primaries should move immediately and exactly the same, but the link connecting them to the secondaries slides freely without moving the secondary levers
3. move the throttle to 1/3 open
4. the sliding stop on the connecting link now contacts the secondaries
5. opening beyond this point opens all 4 carbs, with secondary moving much faster
6. all carbs reach full throttle just as the linkage bottoms out
7. release the throttle, and all linkage returns to normal

 

3 deuces with progressive linkage. Not your run of the mill progressive linkage. I love it because it's made from what appears to be shift linkage.

 

Here is a setup that originally went on a flathead tripower, now headed for the Y block setup.

 

Happy Holidays..Here are a few. The first picture is a good ratio from the primary to the secondaries ..2 to 1 movememnt..
Duane..

 

Damn! That picture of the Howard set up just blew my mind. Wow thats pretty!

 

3 deuces with progressive linkage. Not your run of the mill progressive linkage.

???

How does that work, with the center carb fixed to the rear carb?

 

It doesn't look progressive....just the end carbs open at a quicker rate? That wouldn't allow the ceter carb to reach WOT.......Hmmmmm....

 

Ditto...

~Jason

 

Hey Stromberg 97 have you driven the progressive 5 carb setup with 2&3 as primaries yet (I appologise if I already asked you this).

 

I wrote a quicky bullshit tech post on how I made mine...

http://www.jalopyjournal.com/forum/showthread.php?t=225519

 

Good stuff here!

 

No sliding block = no progression.
Some of those pictures shown set-ups that appear to work, but do not do what you think.
If the block is missing (it can be anything that allows free movement before the secondary linkage is loaded: a slot in the link, a stop, etc.) all carbs will open together, but the primary will not reach WOT.

 

Here are some pictures of my "in progress" 3X2 linkaqge. I am using a Pontiac kit for some of the components and have made a few of the brackets including the coil bracket.
I didn't want to use the aftermarket linkage that uses a longer center throttle shaft and places all the linkage on the passenger side of the carbs. Just an opinion, but I like the cleaner look with the single rod between the secondary carbs.
The secondary baseplates are OEM cast iron units that Hotrod Carburetion modified. I didn't want the aluminum bases that are available from several sources.
The Pontiac linkage works real well and gives the setup a more OEM appearance.

 

THIS IS BEAUTIFUL!

Anybody want to download some of the pics already posted, mark 'em up like this pic, and re-post 'em?

Hell, show us the good and bad of each!

~Jason

 

on my friends car we used bar stock, welded some washers on and drilled the ends for cotter pins. also made a slide and a stop out of bar stock.

 

I redid mine.....hopefully it makes sense! I found it easier to setup the linkage with just the bases mounted first......ensuring that all carbs were getting to WOT at the same time.

 

That piece of slotted kick-down linkage is excellent.

 

who wants to build me a linkage for quad Holley 94s on a caddy 331 motor? PM me!

 

i was curious to what all you guys opinions would be on an idea i have. i would like to take roller chain and sprockets to make a tripower linkage setup. this is still all in my head and not had the chance to mock anything up but the idea much alike using arms and rods. i figure having 2 sprocket on the primary, one that is mounted solid to the shaft while the second floats (spring attached). a mounted pin will run through a cut out guide from one to another allowing the primary to activate the secondary carbs. using an adjustable stop to fine tune the turning of the entire setup. i relise the drawing is very rough but its the genral idea, i also think that the middle sprocket may need to be alittle larger then the other two to keep the chain from saggin. any input would be nice

 

It seems like it would all work fine... I just dont see the advantage over typical lever type linkage. I like the idea though.

 

I think the chain drive would work to run the secondaries.....however, I don't see a need for two sprockets on the primary....just a lever to hook your cable or rod from the pedal and the 'slotted' gear to drive the secondarys.....

 

Ahhh . . . re-inventing the wheel.

Kinda cool.

Think about an idler arm to keep the slop down to a minimum.

There's a progressive sitting in there if you think about it a bit.

Even so, it's hard to beat the non-slop characteristics of a quality Heim joint setup.
Simplicity and easy adjustability is a factor with Heim setups too.

 

Great idea!

~Jason

 

I think it's awesome - dare to be different, man! That's what it's all about...

I say mock it up and post it - there won't be another one around... and that's the stuff that gets a guy into the magazines. Fortune and glory, kid...

~Jason