B Carb on an A?

[Gino]

Hi, met this guy at a swap. He alters a B Carburator ( manifold bolts ) so that it fits an A engine. He recommends it, anyone else? Thanks

[29spcoupe]

I have a B carburetor on an A manifold that has been ported to the size of the B throat. Works great.

[Hitman]

I have a B carb on a B manifold. It works great. I turned the carb mounting bolts to get the carb to rotate and align to fit the A attachments.

[JtownJoe]

Ditto here, just ground down a pair of the carb bolts to allow it to line up.

[MAG]

B Carb on B Intake requires the undercut bolts to align the Carb.
B Carb on A Intake does not require the undercut bolts to align Carb.

[Synchro909]

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B engines and therefore B carburettors were never plentiful over here but I have a B carby on one of my A engines. Because there is a post cast as part of the inlet manifold for the ignition timing mechanism, I had to open up an A manifold (the B manifolds don't have the post).
As for the mounting bolts, I soldered a plate on the manifold flange that accepts the later carby. At the same time, I turned it a little so that the intake is now pointed somewhat towards the engine. This avoids the problem Ford encountered with the carby trying to simultaneously occupy the same part of the time/space continuum as the steering box. Ford's solution was to cut away part of the intake.
All this of course created another issue. The choke rod now did not line up with the carby so I cut the rod and fitted a small universal joint down near the floor and moved the GAV knob a little to the left. It is a "distressed" farm ute so all of this improvisation adds to the character of the vehicle.
Bottom line - Yes it can be done and it does awaken the A engine surprisingly.

[Terry, NJ]

Originally Posted by MAG

B Carb on B Intake requires the undercut bolts to align the Carb.
B Carb on A Intake does not require the undercut bolts to align Carb.

This is what I've found also. The only thing is, you must have a bored out manifold too. Just putting a B carb on a A manifold will not do it for you. Check Pirianios dyno readings for A engines. Incidentally, If you want to buy the tooling, exclusive of the Bridgeport, I've got to for sale, price $25 + shipping.
Terry

[Gino]

Hi, let’s pretend my mother dropped me when I was a baby. Where did you guys have your manifolds bored out? Are the specs available in Les Andrews Book? Terry I’m not sure what you mean by “ tooling. At this point I’m just looking for a dependable carburetor. I found a guy who has two or three that have been altered to fit A Engine. He didn’t say anything about fooling with the manifold. My head hurts thanks.

[Terry, NJ]

Gino! "tooling" means the special tools I had to make to Make the alterations of the A manifold , not to accept the A carb, It will do that easily, but to bore out and polish the runner (About 4" long) to B specs.If you go to my profile and run through my albums. You will see a photo comparison of the A and B carburetors. In Piranios Dyno comparisons, they make it plain about the differences of bored and unbored carburetor Throats. There is a difference in HP. Not a heck of a lot, but when your dealing with 40Hp, a little bit can mean a lot. The A engine, in it's original form is starving for fuel. Think of it this way, you have a garden hose that carries a certain amount of water per second. Then you screw one of those "Y" connectors on the end. Now, the original rate of flow has been cut in half for each leg of the "Y". Boring out the Carb runner and polishing the surfaces of of all three runners will reduce turbulence and increase flow of the fuel to the cylinders.
Good Luck!
Terry

[jack backer]

Gino, 1.25” is the optimal center runner bore size to run a B carb. Ford grey iron castings machine easy, I’ve done A manifold modifications with a drill press and a 1.25” bit, two schools on intake polishing, I’m in the one that doesn’t.

[Dave in MN]

Guys,
I have a sequence of photos that shows the process of enlarging the primary passage of a Model A intake manifold on my website. Look on the DIY Help page for the link.

My website: www.durableperformance.net

Good Day!

[Gino]

Ask and you shall receive! Great info, pics and tutorials. I’m going to soak and rebuild a Zenith A Core that I have laying about. I’m probably not going to put my best effort onto it so I won’t be emotionally invested in it. Should it fail I’m going from A to B. I’ll be back, thanks very much!

[Terry, NJ]

Things to remember about A and B carburetors!
!) "A" and "B" Carburetors , both have removable venturi's and are "fitted" into both halves of the body. Both are made from die cast, pot metal and are fragile. Both sometimes get stuck (For whatever reason) and can make the two halves very hard to get apart. Use a little heat (Not a lot) propane is plenty

2) Never try to twist it apart! There are small tubes which can crush or break. Either solvent or heat or both and the a straight pull after a light tapping around the outside.

3) Be very careful when taking the carb. off the manifold (especially the B s) the ears break off very easily. It's very common to find B carbs with broken mounting ears.

4) One advantage of a B carb. is the little accelerator tube that extends across the two halves, But it is very fragile. Another thing to be careful of when disassembling.
Good Luck, Terry

[Chuck Sea/Tac]

[QUOTE=Terry, NJ;2122575]


3) Be very careful when taking the carb. off the manifold (especially the B s) the ears break off very easily. It's very common to find B carbs with broken mounting ears.

FYI so is the late 31 sidebowl carb.

[Gino]

Thought someone might want to know. Right now I’m soaking a Zenith A Core in various solutions. Also cleaning it out with thin wire. I hope this works and I think it might as I’ve talked to a few guys who have had more success this way than “ Rebuilders”.

[Synchro909]

Originally Posted by Gino

Thought someone might want to know. Right now I’m soaking a Zenith A Core in various solutions. Also cleaning it out with thin wire. I hope this works and I think it might as I’ve talked to a few guys who have had more success this way than “ Rebuilders”.

Please let the forum know how it goes and what solutions you find will work.

[Oldgearz]

The addition of the Power Jet in the B carb makes a world of difference to an A's performance. The engine no long has to rely solely on the GAV for extra gas.

[ursus]

A fellow told me that he had enlarged several A intake manifolds to 1.25" ID by means of an adjustable reamer. It wasn't a fast process but it required no special tooling or fixtures. I plan to try it myself.

[Synchro909]

Originally Posted by ursus

A fellow told me that he had enlarged several A intake manifolds to 1.25" ID by means of an adjustable reamer. It wasn't a fast process but it required no special tooling or fixtures. I plan to try it myself.

I enlarged mine with a small die grinding stone on a 1/4" dia. shaft (from any hardware store) in the pistol drill. It took a while but it worked. I checked diameter with a 1 1/4" X long enough to go all the way in and something to hold onto.
Likewise, no special tooling or fixtures

[Gino]

Because Syncro asked, I’ve had the old rusty core soaking in “ Zip Stripper” for about a day and a half and the results are great. This product is a floor wax remover, do not confuse it with (Zip Strip). Zip Strip is a paint remover. All the crap and rust is coming off including rust that I was unable to get at. I was made aware of the product from a guy I met at a swap meet, he said I should soak it for a week, $11.95 gallon. Smith and Jones Janitorial Supplies & Equipment,West Columbia SC. Please keep in mind, I’m in the I hope this works stage. I’ll be back!