WCFB 2X4 Choke Problems

[Pierre J.]

I suspect I have the wrong coil spring behind the choke cover, does anybody have any suggestions on how I can fix this problem or knows where I can buy the correct choke coil spring for such WCFB carb configuration?

Thanks,
Pierre 34410

[Bob B.]

Re: WCFB 2X4 Choke Problems

Pierre,

Try giving Bob Kunz a call at 1-314-845-2566. He can either tell you what to do or provide the right part.

Bob

[Stuart F.]

Re: WCFB 2X4 Choke Problems

Pierre;

By any chance are using hedders in place of the original exhaust manifolds? Or are you using an aluminum heat tube in place of the steel?

Reason I ask is I had a similar problem which is basically a matter of not providing the choke housing with a good heated air supply. As you may know, there is an "X" shaped tube in your passenger side exhaust manifold through which the vacuum of your engine draws air through the steel tube into the choke housing to provide the heat to relax the choke spring. I say "X" because the tube is pinched into an "X" shape to restrict (slow down) the air being drawn in so it is exposed to the heat in the manifold longer. Without adequate heated air, the choke spring cannot relax enough to release tension on the choke linkage to allow the choke to be pulled full open by the choke pull off. Then it becomes a "catch 22"; you adjust so it will open fully, then it won't choke fully - you adjust to get full choke, then it won't release fully.

I had hedman hedders on my 57 Chevy 270 and I tried to make a heat tube using aluminum tubing; I wrapped tubing around one hedder tube and used a brass coupling to the section of tubing to the choke housing. I still had the above described situation (catch 22). So, first I insulated the upper tubing section - that helped. Then I took a clue from the original manifold X-tube, and got out my vice grips and pinched the tube from the manifold, setting the depth of pinch so as to just squash it down enough to restrict it. One pinch helped, then a second 90* from the first, even better, then a third pinch 90* from the second - Wa La! It worked like a charm - as good as stock. My next project was to adapt an overdrive kick down switch. Even more fun.

Stu Fox

[Pierre J.]

Re: WCFB 2X4 Choke Problems

Pierre;

By any chance are using hedders in place of the original exhaust manifolds? Or are you using an aluminum heat tube in place of the steel?

Reason I ask is I had a similar problem which is basically a matter of not providing the choke housing with a good heated air supply. As you may know, there is an "X" shaped tube in your passenger side exhaust manifold through which the vacuum of your engine draws air through the steel tube into the choke housing to provide the heat to relax the choke spring. I say "X" because the tube is pinched into an "X" shape to restrict (slow down) the air being drawn in so it is exposed to the heat in the manifold longer. Without adequate heated air, the choke spring cannot relax enough to release tension on the choke linkage to allow the choke to be pulled full open by the choke pull off. Then it becomes a "catch 22"; you adjust so it will open fully, then it won't choke fully - you adjust to get full choke, then it won't release fully.

I had hedman hedders on my 57 Chevy 270 and I tried to make a heat tube using aluminum tubing; I wrapped tubing around one hedder tube and used a brass coupling to the section of tubing to the choke housing. I still had the above described situation (catch 22). So, first I insulated the upper tubing section - that helped. Then I took a clue from the original manifold X-tube, and got out my vice grips and pinched the tube from the manifold, setting the depth of pinch so as to just squash it down enough to restrict it. One pinch helped, then a second 90* from the first, even better, then a third pinch 90* from the second - Wa La! It worked like a charm - as good as stock. My next project was to adapt an overdrive kick down switch. Even more fun.

Stu Fox

Thanks for your response Stu. I do have the stock exhaust manifold and the steel choke tube. I know the exhaust manifold tube is there but didn't realise about the restrictions in it. I've seen them for sale in various catalog, so Im guess that will be my next project. I take it that they come out from the top and are pushed (hammered) out from the bottom?
Pierre

[Stuart F.]

Re: WCFB 2X4 Choke Problems

Pierre;

It's been a while since I replaced one of those tubes, so I can't recall if they need to be driven out from the top or bottom. If you were to take the manifold off for this purpose, it would be self evident. Usually what goes bad with them is the tube burns through and the carb starts pulling exhaust laden air (like an early version EGR valve), but the carb don't like that stuff and it gets all crudded up big time. I suppose it is possible for them to become plugged - the fact that in later years GM thought to pull clean air from the carb or air cleaner via a tube and hose arrangement through the tube in the exhaust manifold attests to the possibility that they indeed had such a problem. I would hate to ask you to put your finger on the lower hole (tube end) to see if there is suction, but perhaps a piece of paper might work. I don't know how else one could check that air is being sucked into the tube. Maybe someone else or another C-1 owner can comment about their similar experience.

Stu fox

[John H.]

Re: WCFB 2X4 Choke Problems

I take it that they come out from the top and are pushed (hammered) out from the bottom?
Pierre

Pierre -

The internal choke heat tube was installed from the bottom (and staked in place there), and has to come out the bottom. If your choke blade closes properly and then goes full open when the engine starts, I'd take a look at the choke unloader adjustment - the 1961 Passenger Car Shop Manual has an extensive section on WCFB rebuild and adjustments.