The Stovebolt Site Forums The Shop Area Engine Shop AFB carb set up. Will this work?

Question on setting up a heat source for the choke. Carter AFB carb. I drew up a quick picture to see if it would work or not. Never set one up before so I would like to see what yall think. Here is the pic.

http://talk.classicparts.com/picture.php?albumid=180&pictureid=1541

I think this is how it should work.

One question I have is if the tube is one piece and wraps around the exhaust manifold, how could any heat get to the spring on the choke? It seems the suction from the air cleaner side would draw all of the heat.

How big an engine are you planning on running? An AFB will supply enough air to run about three 235's.
Jerry

Hy GrandpasTruck, I agree with Miner54, there is vacuum supplied to the choke thermostatic spring housing, so if you wrap your hot air tube around the exhaust manifold leave it open ended so the vacuum at the choke can draw the hot air into the choke housing. If you leave it as you have drawn it, as Miner54 said the low pressure in the air cleaner will compete with the vacuum in the choke housing, causing a poor function at best, hope that helps.

If there's enough low pressure in the air cleaner to restrict the flow, he needs to change the filter element. The AFB won't work, and neither will the diagram as it's drawn.
Jerry

About forty-eight years ago ('63) I was just a youngster of 21, but I was the lone night parts man at a Chevrolet dealer ship. We GSD's an AFB rather than rebuild it the put a new one on the customers car. We were supposed to destroy the GSD'd parts but that one slipped thru the fence and ended up at my place. Back then I was just a dumb kid and didn't know all about fluid dynamics and CFM specs and all that jazz so I went ahead and mounted the carb up to my other wise stock ’60, 235. The Graham’s always had machine tools in the basement and my dad and I took a 235 manifold and milled the intake box off and opened up a pocket so we could brazed a box and flange on it to take the AFB.
Well it ran, and it ran fine, it didn’t have any better acceleration that it did with the Rochester B but one thing it did have was top end. I could bury the speedometer, which I couldn’t do with the Rochester. Downers Grove was out in the boonies and there wasn’t as much traffic back then. And, we were kids so we could get away with crazy things like speeding, drag racing, running a California rake, drinkin’ a few beers out on a dirt road, smokin’ Lucky’s and such.
Not sure how that AFB would have performed had I re-jetted it, done some head work, installed a hot cam and increased the displacement. Uncle Sam got me for the rest of the 60’s and by the time I got discharged we were into midgets and I didn’t see another Stovebolt till five years ago.

Denny Graham
Sandwich, IL

cool story Denny. anyone know if those carter afb's worth anything? i got a couple of cores at a auction the other day.

It is going on a 235. And the copper hose is rapping around the exhaust. I ran the hose to the air cleaner just for clean air but I could run it else were as well. Some people say it was ran from the exhaust at one point??? I know the carb has a vacuum but not sure were the air comes from.

Here is a new pic. Would this work better?

http://talk.classicparts.com/picture.php?albumid=180&pictureid=1543

I would suggest steel tubing, and silver solder it to the manifold for better heat transfer. Nothing wrong with drawing the air from the clean side of the air filter, possibly with a rubber grommet through the housing with the tube inserted into it. The AFB is way too much carb, unless you're running a 300 cubic inch engine or so.
Jerry

Carter made AFB's in sizes from 400 CFM to 950 CFM.

I have put the 400's on a number of small engines successfully. While I have never put one on a 235, I have installed them on a Pontiac 195, and also a non-USA 134.

A 400 should work well on a 235. Although not sure I would want to put one on a 235 with an auto trans.

Jon.

Cool, Thanks guys. It is a 400CFM Carburator. And it has a manual trans. Ill try the steel tubing and run it from the air cleaner just to see how it works. Ill post some pics once I get it all done up sooner then later I hope.

Thanks all

While the copper tubing would probably work, you might want to consider:

http://www.thecarburetorshop.com/Heatstovefabrication.htm

Jon.

Ok, Figured out how this works. Found a set up they use to use. Ran from the air cleaner threw the intake back into the choke.
Here are the pics I found. Was for a V8 but same idea.

http://webcache.googleusercontent.com/search?q=cache:hG2qEck2O1cJ:www.chevelles.com/techref/Adjusting_Automatic_Chokes.htm+hot+air+choke+operation&cd=10&hl=en&ct=clnk&gl=us&source=www.google.com

Only about 1/4 to half way down the page are the piccs.

A good carb shop should be able to put an electric choke on an afb

The Edelbrock Performer electric choke kit fits the old AFB,s.