Hey guys, I am needing a little information on the dual carb set up I have on my 1956 Cadillac, especially with the dual choke system. As you can see in the picture below, there is a tube that runs from one choke housing to the other. That tube is missing from the carbs that I have. What I am wondering is how do the chokes operate? I am used to heated ones, and cannot see on the above pic how those cold possibly get enough heat without the end of the tube connecting to something. Is there a piece missing that connects to the exhaust manifold somewhere? I am assuming that this part is super hard to find, and I should go about figuring out a way to fab up one of my own. Any help would be appreciated!
I responded to your resurrection thread... I think there should be a tee in the line, also leading down to the heat chamber in the passenger-side exhaust manifold.
that picture doesn't make sense. There has to be a piece going to the tube in the intake manifold exhaust crossover or the exhaust manifold.
Check this out: Might have to watch it a couple of times. There is a shot early (around 11 sec. mark) showing a choke tube with a "T". Looks like it might lead to exhaust manifold. There's a later shot (1:20) showing a line after restoration is completed. Hope this helps!!
It's a Cadillac.....it's not about needs. You really think a car "needs" dual quads, auto closing trunk, auto dimming headlights etc.
Chstitans42 - can you replace those choke springs with an electric unit that fits into the housing? Or is this a restoration situation?
Sounds to complicated to do the electric conversion. To much linkage is attached. Unless you can find someone who makes a specific kit for Cadillacs to retain the linkage. It's way easier and cheaper to fix what's already there. It's just tubing.
If the heated shokes are working there is no reason in the world to go electric, those old heated chokes work fine. If you look at the vid there is a tube coming out of the exhaust crossover between the carbs that should be your heat source for the chokes. the tube that ties the chokes together needs to be Td and hooked into the outlet from the exhaust crossover. The way that those chokes work is that they have the stove (spring) inside the choke housing instead of in the intake like a Chebby or a Ford. The carbs are like the carbs on a Buick of the same era same type of choke as well. It needs to chokes because it has the idle circuit functional on both carbs. it is cheaper and easier to set up that way. Yes you have to trim two carbs instead of one but you don't have to have a secondary specific carb, just another one off the shelf.
I agree....except that the front and rear carbs aren't exactly the same. There is something different about the rear carb but can't remember what it is at this moment.
You'll think of it, and if you never do then I will look really smart. Make sure that I know when you do so I don't look as dumb the next time. OK?
That's not my intention.....but I think it was a fairly minor difference that would only matter in a top notch restoration. You could actually use two front carbs and it would work.
I know that it is not your intention, I just want the information to store in my list of things that someone may want to know someday. The truth is that every time I look foolish someone else learns something important and I am a clown by nature. Your not an ass and I figure that anyone can say anything that want as long as it isn't spoken in malice. Some folks don't agree with my philosophy but they'll just have to get over it.
You two must be on another plane (bound somewhere), All I could come up with; was no idle screws on a second quad. (mayhaps accel pump linkage changes)
I maybe have never seen a stock setup I don't remember any that I have seen without idle circuits and needles. Of course I never played with one until the late '60s and it could have been a junk yard setup by then. You know rodders whatever was at hand would work with a little imagination.
The mutual admiration society, you gots to know the secrete hand shake. I remember fiddling with a couple way back when (my cad mill in the '46 was a 3 deuce mill) and trimming the carbs. Someone told me there is an art to trimming two carbs, I dunno I just do it. Anyway all of them that I fiddled with both carbs had trim screws. Thus my conjecture that they had two chokes because both carbs were operational all the time. I guess that one carb could have been fixed idle and still have an idle circuit like a '70s emission car. Some of those you had to drill stuff out so that you could adjust it.
Pretty sure an original stock cad System only had one choke on the primary carb The secondary carb did not require a choke The primary was the rear carb
Each GM 2 x 4 setup I saw was done this way. Your rear primaries feed the center region of the manifold
I don't recall seeing a GM with the front as the primary carb a either. A lot of them had a taller carb pad for the rear carb as well which helped performance on the single primary carb some.
At least in '55 the dual quad motors had chokes on both carbs, and the idle air was metered by the large needle valve on the side of the throttle body. Also, since they didn't have progressive linkage there were no primary or secondary carburetors... don't think anything changed in '56.
I don't know specifics on the choke set-up, I just got the intake with my motor. what I don know about the 2 x 4 setups (at least the 57 model with is notoriously bad for on-off stuff) is that 1) they are not progrssive. it's 4bbls on two carbs out fo the hole and and all 8 when you nail it. something about fuel flow and making sure all the cyliners have fuel. 2) the original carbs were two differnt sizes. one was like 390 cfm and the other was like 410 or something wierd like that. I did a lot of research into this 15 years ago when I was looking at running the setup on my old delivery. what I learned is that if you want a factory correct set-up be prepared to pay out the wazoo for the right parts. restorers will spend a fortune for the "right" carbs. edelbrock's work just as well for a whole lot less money for a hot rod IMO. and don't get me started on that stupid batwing air cleaner assembly for the 2 x 4's
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