Model B carb on a Model A

denniskliesen

denniskliesen

Well-known member
I can make it fit. Is there an advantage or disadvantage to a Model B carburetor. Anybody done it here?
Thanks for anybody's advice.
Dennis
 
One of the tricks to make it fit, which you may have already discovered, is the bolts that the vendors sell that are cut to allow the carburetor to be rotated sightly to make it line up. It is a larger diameter and should give a couple of extra horsepower but you need to hog out the Model A intake manifold of run a Model B manifold to get the benefit.

Charlie Stephens
 
With the float bowl mounted sideways it is not a susceptible to stalling at sudden stops. Yes with a bored intake it can give you 10% boost in HP.
 
Good Morning...I have been running a B Carburetor with a B intake for about 12 years on an early 1931 Tudor. I love it and it does give a bit more power. If you can get one, run it. You can drill out the A intake if you have to or easier yet, take the A intake to a machine shop and let them drill it out for you. Ernie
 
I have run an B Carb on an A manifold with no modification to the Carb or bolts. I think that you need to do the Mods if you're going to use an B manifold. I would use an A manifold , but port and polish it first. That means getting some long grind stones with an arbor to put in your 1/4 (?) drill. I would first drill the carb runner out to between 1 1/4 (1.250) and 1.300and polish it. Next I grind the mouth of the other two runners to match the gasket (Size and location) and then clean up the runners as best I can. This will give you about 3-4 HP 10% 0f 40 HP=4 HP . Check Pirianos site on Mod A HP. If you leave the A manifold the stock, unpolished 1 ". you will get very little increase. And if you port and polish the A manifold and use the A carb you will notice a slight improvement. Be careful with a B carb as the mounting ear on the rear break easily. A parts don't fit a B carb but B parts are available from the vendors. As has been said, The B float is mounted crosswise and the B carb is not so prone to stalls with sudden stops. Good Luck!
Terry
 
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Is a B carburetor balanced so you can use a air filter on it? Or does that need to be modified.

Terry, so you open the carb itself up above the throttle plate? Doesn't sound too hard to open the intake and carb. I have a boring tool I can chuck up on my lathe to open the manifold. dingle berry hones etc.
 
"Terry, so you open the carb itself up above the throttle plate? Doesn't sound too hard to open the intake and carb. I have a boring tool I can chuck up on my lathe to open the manifold. dingle berry hones etc."

No Dennis, I think Terry means to open up the primary carb runner of the intake manifold...not the carb.

I have a visual explanation of the process on my website.

On my website, go to the DIY Help page and open up the Intake Manifold Enlargement article.

my website: www.durableperformance.net

Good Day!
 
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No, no! No modification to the carb itself, only the manifold. Do you have a Bridgeport? If so, bore the primary runner out to 1.250-60 +, then polish to 1.280 +. Just keep it under 1.300, the walls are getting thin! Then align the ports with the gasket (1 piece) and clean them up. These manifolds are still rough castings inside, lots of obstructions to good flow.
If you can keep the engine clean (But only if, don't try it if the grit is going to get in the engine ) Round out the ports in the block and match the gasket. Again, Don't try it if you can't be sure of keeping all the grit out of the engine.
I'm afraid there isn't much work for a lathe, only a Bridgeport!
Terry


denniskliesen said:
Is a B carburetor balanced so you can use a air filter on it? Or does that need to be modified.

Terry, so you open the carb itself up above the throttle plate? Doesn't sound too hard to open the intake and carb. I have a boring tool I can chuck up on my lathe to open the manifold. dingle berry hones etc.
Click to expand...
 
Dennis, I ignored the first part about the air filter. So to correct that I'm going to say I have not seen any air mazes that are for a B carb, only A bores. Chances are that they make them, it's just that none have come my way yet. If your lathe has enough swing, you could make a fixture out of a faceplate and an angle plate to hold them and bore them deep enough to get them on your B carb. Set up would take some time but once that was done the actual cutting would go quickly. Also, you may find a B carb with a broken ear and be able to save it by making a base plate from steel and brazing it on to the base.
Terry



denniskliesen said:
Is a B carburetor balanced so you can use a air filter on it? Or does that need to be modified.

Terry, so you open the carb itself up above the throttle plate? Doesn't sound too hard to open the intake and carb. I have a boring tool I can chuck up on my lathe to open the manifold. dingle berry hones etc.
Click to expand...
 
Terry, and everybody else, thanks for all the information. I noticed on Vince's site there a couple (?) air filter/sound reducers. One of his samples had a screen in the bottom.
 
Just thought of something. Model B had a fuel pump, I have an electric pump with a filter ahead of it but not sure of the relief pressure and would have to get a regulator I'm sure. What should the running pressure be set at?
 
I've got a B carb bolted to my 1929 A intake...no boring out anything, just bolted on...works great, no problemas. I'm not looking for hp gain, it's just the way it came to me.
 
D. Get the A manifold bored out to B specs and it will run even better. You're processing more air through that larger throat and then choking it down.
Terry



d. said:
I've got a B carb bolted to my 1929 A intake...no boring out anything, just bolted on...works great, no problemas. I'm not looking for hp gain, it's just the way it came to me.
Click to expand...
 
No it works fine on a gravity feed. But I almost forgot, You'll need different plumbing on the fuel lines. Either a couple brass fittings or a custom line, made and sold by B&B a parts, here in Pa. I think he gets maybe $15 for one. I grabbed one from him, it has all the right bends for a B carb. Check the vendors, Like Brattons. I don't think B&B is too well known outside the state.



denniskliesen said:
Just thought of something. Model B had a fuel pump, I have an electric pump with a filter ahead of it but not sure of the relief pressure and would have to get a regulator I'm sure. What should the running pressure be set at?
Click to expand...
 
Terry said:
No it works fine on a gravity feed. But I almost forgot, You'll need different plumbing on the fuel lines. Either a couple brass fittings or a custom line, made and sold by B&B a parts, here in Pa. I think he gets maybe $15 for one. I grabbed one from him, it has all the right bends for a B carb. Check the vendors, Like Brattons. I don't think B&B is too well known outside the state.
Click to expand...

Are they tapered pipe thread? I have a local hardware store that has a good selection.I'll have to check out B&B. Got a link?
 
No they're a straight machine thread, !/2 X 20 or 7/16 X 20 (Can't recall) The one Bill Savitz Makes and sells is perfect, Mine still has the tag on it $9.75! The name is B&B Mod A Ford Parts, 8752 Breinig run circle, Breinigsville, Pa.
Bill used to run B&B from Phillipsburg Nj, but he's getting old and gave up a lot of it. He still sells Carbs and distributors and small stuff and these fuel lines. The only one I know of who makes them. I can't recall seeing them anywhere else. I don't have a Phone number yet, but when I find his card, I'll forward it onto you. 610-928-0988 Don't tell him I gave you the number. He doesn't know me, I just bought a few things from him and remembered him. I had his card, but can't find it now. Good Luck!
Terry



denniskliesen said:
Are they tapered pipe thread? I have a local hardware store that has a good selection.I'll have to check out B&B. Got a link?
Click to expand...
 
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If you're running pressured fuel then leave B carb stock. If gravity, the remove the baffle . As I recall? I've been using a B for years. Also, as mentioned, like the late 31, the ears a thin, so tighten in increments. Especially,if like me you put a insulating spacer between carb and manifold to help with heat vapor.
 
Chuck Sea/Tac said:
If you're running pressured fuel then leave B carb stock. If gravity, the remove the baffle . As I recall? I've been using a B for years. Also, as mentioned, like the late 31, the ears a thin, so tighten in increments. Especially,if like me you put a insulating spacer between carb and manifold to help with heat vapor.
Click to expand...

Chuck, is one of those 1/4" thick spacers adequate?
 
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