Anyone use a "B" Carburetor?? thoughts??
- Thread starter msmaron
- Start date
msmaron
Well-known member
Mike...yes... seems that Renners corner supplies everything and will do the bore also..Do you run one on any of the cars?
Mitch//pa
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here is a pic
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Purdy Swoft
Well-known member
Thanks Paul ,I agree the Model A manifold needs to be enlarged for best results. When I ran a single B carb on the coupe with stock cam and head, I could notice some improvement in higher speed acceleration and slightly higher top speed. When I added a Mallory dual point distributor and a 5.9 head there was a big improvement. The Piranio dyno tests show that the C head increases the horsepower on a stock model A engine close to seven horsepower. The model B engine was rated at 50 horsepower. If you ran the C head, B cam, B carb, B intake and distributor, you would have near a 10 horsepower increase. If the head gave near seven hp. that only leaves only a little over three horse power increase for all of the rest of the B parts. Improved manifold design as with some of the older aftermarket manifolds will help a lot. I run dual updraft intake manifolds on a couple of mine with B carbs and really like them. I get around 20 mpg with dual B carbs on my roadster and only get around 17-18 mpg with my stock 31 tudor with single side bowl Zenith 1 carb. The roadster does have benefit of a 5.9 head and winfield grind 3/4 cam.
When Zenith quit making the model A style Zenith carbs, Ford sold a replacement carb for the model A that was actually a model B carburetor with a smaller venturi.. Be sure that you have the large venturi or there will be little or no gain.
Purdy Swoft
Well-known member
The model B carb will fit the model A manifold and line up with the choke and GAV with no modification. The model B intake manifold has a slight offset at the carburetor flange and the kit pictured by Mitch above will let things line up. The model B intake has larger runners and the flat top aids fuel distribution to the cylinders and gives a smoothing effect. The Simmons Swan design type manifolds havre been said to give the smoothness of an inline six.
H. L. Chauvin
Well-known member
On my 1930 Model A Coupe, ran my B intake manifold on a my B engine over 50 years ago with B carb, B distributor & Police Head.
No stock Model A could keep up with either my top speed or taking off in drag racing.
No stock Model A could keep up with either my top speed or taking off in drag racing.
Walt Dupont--Me.
Well-known member
Reading this long thread there is mention a few times about using a B dist on an A engine. SO, I understand the B dist has only 11 degrees mechanical advance. NOW, if your using an A timing cover and set the timing with the pin at TDC you only getting 11 degrees advance at speed. The B cover using the pin is timed at 18 Degrees BTC, so at speed you will have 29* at speed. BUT, I like to set at a street light and retard the spark lever on my A and have it idle at TDC. I have used both dist but I like the A dist better, I can play with the spark where it run the best. BTW- I have a 31 coupe with a B engine .060 overbore, 35# flywheel, Police head milled to about 6.1 compression ratio, made my own intake with a 216 Chevy Rodchester carb, B trans with 46 Ford gears, 3:54 rear gears, timing pointer on front cover with TDC mark on pulley, AN A DIST, timing set at TDC, with spark lever pulled all the way down timing mark is 35* BTDC checked with adjustable timing light. At 55-60 mph 35* is to much so I just push the spark lever up a little. I realize a lot of people nowdays don't know what is happening when using the spark lever so probably there better off with a mechanical dist. Walt
H. L. Chauvin
Well-known member
Here is an excellent explanation of timing differences between "A" vs. "B" distributors:
http://www.fordgarage.com/pages/bdistributoradvance.htm
In checking two (2) timing covers, one at a time, each bolted to a piece of the same cardboard, & in marking different timing pin locations, one can verify that on the timing gear the "B" timing pin is 9-1/2 degrees more advanced than the "A" timing pin location.
Because the crankshaft turns (2) revolutions for every timing gear revolution, the crankshaft should be advanced 19 degrees when timing an "A" engine with an "A" timing cover while using a "B" distributor.
If one is using an "A" timing cover with a "B" distributor, at No. 1 piston TDC, (timing pin slipping in, the initial timing should be set at 19 degrees BTDC in lieu of TDC; then with the additional maximum of 17 degrees centrifugal mechanical advance at high speeds, the "A" engine with a "B" distributor runs at 19 + 17 degrees = 36 degrees -- recommended for higher compression heads.
If using an "A" timing cover with a "B" distributor, there is a neat $35.00 timing device listed on E-Bay for timing Model "A" distributors whereby one can file a mark at TDC for "A" distributors on one's crank pulley, & file another mark on the crank pulley to occur at 19 degrees BTDC where indicated on the timing device if one wants to switch to using a "B" distributor.
"Easy-Peasy", as my (6) year old grandson remarks.
http://www.fordgarage.com/pages/bdistributoradvance.htm
In checking two (2) timing covers, one at a time, each bolted to a piece of the same cardboard, & in marking different timing pin locations, one can verify that on the timing gear the "B" timing pin is 9-1/2 degrees more advanced than the "A" timing pin location.
Because the crankshaft turns (2) revolutions for every timing gear revolution, the crankshaft should be advanced 19 degrees when timing an "A" engine with an "A" timing cover while using a "B" distributor.
If one is using an "A" timing cover with a "B" distributor, at No. 1 piston TDC, (timing pin slipping in, the initial timing should be set at 19 degrees BTDC in lieu of TDC; then with the additional maximum of 17 degrees centrifugal mechanical advance at high speeds, the "A" engine with a "B" distributor runs at 19 + 17 degrees = 36 degrees -- recommended for higher compression heads.
If using an "A" timing cover with a "B" distributor, there is a neat $35.00 timing device listed on E-Bay for timing Model "A" distributors whereby one can file a mark at TDC for "A" distributors on one's crank pulley, & file another mark on the crank pulley to occur at 19 degrees BTDC where indicated on the timing device if one wants to switch to using a "B" distributor.
"Easy-Peasy", as my (6) year old grandson remarks.
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Jerry in Shasta
Senior Member
Try to find a "B" manifold. not only is the throat larger but so are the runners.
Not only do I use a "B" barb. and manifold, but I have also ported the intake ports in the block to match the manifold.
That made a noticeable difference at least for the first few times I drove it.
JIS
Not only do I use a "B" barb. and manifold, but I have also ported the intake ports in the block to match the manifold.
That made a noticeable difference at least for the first few times I drove it.
JIS
Purdy Swoft
Well-known member
I also did port work on this one, I matched and enlarged the intake ports but didn't polish them. I smoothed out and enlarged the bowl area under the iuntake valves. I smoothed up the rough cast in the exhaust ports but didn't really enlarge them. It all works together with the other mods. Here is a pic of our Trojan intake and B carbs. The manifold and carbs are the only noticeable mod. The roadster seems to have the power of a modern car but wouldn't run as fast on top end. We usually like to cruise at 50 mph and have power to spare for hills or passing. It idles good and the choke and gav works the same as original. You don't have to push the accelerator button as far to accelerate.
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Purdy Swoft
Well-known member
Thanks, Tiny for the kind words, I get a kick out of it myself!!!!!!! I wanted a setup like that since i was a kid. You can only imagine how thrilled I was to finally find the manifold and set it up on our roadster.
Purdy Swoft
Well-known member
The Trojan intake stands out a ways farther from the block than the original intake. I had to drill another hole for the choke rod a bit to the right of the original hole for the choke rod to align. I also had to lengthen the choke rod and bend the arm on the accelerator assy. a bit. Nothing major, just common sense stuff. The Trojan was made for model A carbs. I ground a taper at the flanges of the intake to match the throittle bore of the B carbs. This setup performs good but not as good as the Uni-Flow intake on my speedster. The Uni-flo manifold is a swan design with LARGE runners. It was built after 32 for the larger bore carbs. When the high speed jets kick in you can really feel the power surge. This one fits closer to the block and the rear carb is slightly angled to clear the exhaust manifold. Here is a picture of the Uni-Flo setup on my speedster. This is an older pic before the Mallory dual pont dist. but you get the idea.
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Purdy Swoft
Well-known member
Looks real good!!!
TDO
Senior Member
I'm running a B carb. on my 30 coupe, stock head, bored to 4 inch with touring cam. I haven't bored the manifold yet. My driving is done on crooked roads and lots of hills here in WV. Can not keep a constant speed, but have a lot better performance with the B carb. Can't tell much difference in gas mileage. I get around 17 mpg. I'm also running 16 inch tires
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TerryNJ
Well-known member
Just for kicks, I bored out an A manifold, and got more power with the A carb. I put the B carb on and it ran pretty strong, but I had to go back to the A while I adjust the B. Now, If you have access to a Bridgeport or similar machine, Make a plug, locating pin, whatever with a 1/2 shank to find center of the hole. Locate center of the intake port in the manifold. I use a 1.250 drill, which I grind to cut oversize.Drill it all the way through till you feel the tip hit the bottom. Then polish a little with an 1 1/2" flap wheel. This rather simple little trick will gain you a couple of HP. (2 HP = 5% increase)
Terry
Terry
Phred
Senior Member
Mark,
My '30 sedan had a similar updated engine, and I played around with various A and B distributors and carbs/manifolds. While I tried to apply a bit of scientific method in my experiments, I would probably still claim my results to be anecdotal. My main assumption was that my updated engine could use some improvement in breathing to maximize its "updates".
Using the A carb/A manifold as a benchmark:
The B intake manifold made a top end improvement with both the A and B carbs. I would expect a bored A manifold would not be a detriment.
The B carb seemed to pull a bit stronger to top speed (probably due to slightly larger venture and having a power jet circuit).
I never have check fuel mileage, but noticed no real difference.
Have fun, but be careful... you may soon want a downdraft on the engine and a dog on the radiator cap!
Peace and Happy New Year
My '30 sedan had a similar updated engine, and I played around with various A and B distributors and carbs/manifolds. While I tried to apply a bit of scientific method in my experiments, I would probably still claim my results to be anecdotal. My main assumption was that my updated engine could use some improvement in breathing to maximize its "updates".
Using the A carb/A manifold as a benchmark:
The B intake manifold made a top end improvement with both the A and B carbs. I would expect a bored A manifold would not be a detriment.
The B carb seemed to pull a bit stronger to top speed (probably due to slightly larger venture and having a power jet circuit).
I never have check fuel mileage, but noticed no real difference.
Have fun, but be careful... you may soon want a downdraft on the engine and a dog on the radiator cap!
Peace and Happy New Year