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10-26-2014, 11:52 AM | #1 |
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Model a vs b carburator
Ive got a stock A motor with a B distributor. having a choice between a model A zenith carb and a model B carb for the same money will there be any noticeable improvement by going to the B? Thoughts?
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10-26-2014, 03:26 PM | #2 |
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Re: Model a vs b carburator
It appears your question involves three (3) things; i.e., money, improved performance, & choice between an A or B carb:
I would guess you would be happy with the B, not because of money, & not performance which will not be much better with a stock A engine; however, because of your interest in performance, if you have the B carb, & later try out an enlarged A intake, with a higher compression head, & a higher lift cam, you will be glad you chose the B carb. Just a guess. |
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10-26-2014, 03:53 PM | #3 |
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Re: Model a vs b carburator
I agree. You may get a small increase in top end with the B carb if it has the large venturi but you won't feel the difference. You will need higher compression, either a model B intake or a reamed out model A intake and probably a better cam to feel any real improvement as Mr. H.L. says above .
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10-26-2014, 04:15 PM | #4 |
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Re: Model a vs b carburator
I don't know if this is any indication of the good or bad features of a B carb but it is just my observation so far with the B carb on my huckster. The B carb has been on my rig ever since I owned the chassis. When I converted to the huckster body, the engine rebuilder left the B carb on the motor and rebuilt it also. My huckster weighs about 2700 pounds, a little heavy for Model A's. The huckster has everything stock except for the B carb.
So what I have found is that with the huckster (with the B carb) I get about 15 or 16 MPH. While with my coupe which is also all stock and has an A carb, I get about 20 to 21 MPG. What I had planned to do is put an A carb on the huckster and then check the millage again to see if it makes a difference of not. Have not done this yet so don't know if the lower MPH on the huckster is due to the B carb or the weight of the huckster Sorry I don't have better info for you at this time but just thought I would share for what it is worth. Maybe others on the Barn have had similar experiences and can comment.
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10-26-2014, 04:40 PM | #5 |
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Re: Model a vs b carburator
Purdy, One if the simplest mods you can do is to bore your intake to B specs. I use a 1.250" drill in a Bridgeport. It can be done with an angle plate on a drill press too. The Bridgeport is better, but..... Go the full length and then polish it with a 1 1/4" flap wheel. It may take as long as a half a hour. Whoa...,wait You'll need a locating Pilot that fits in the chuck, about 1 3/16 dia. and 2 1/2 or so long. Sorry about that! As long as the manifold is off, put some polish on the intake ports too. With either the A or B carb, you'll feel some difference, but more with the B. My own A has a rebuilt (about 3 years old) Zenith A carb. When I switched to the B, I got some idea what it would be like if it were running good. One of these days, I'm gonna bore the air intake out .020-.030 or more of a B carb. (They're pretty thin) and see if I can make some real difference. But I'm looking at a tough setup and a lot of time on the lathe. For now I just want it to run.
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10-26-2014, 11:05 PM | #6 |
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Re: Model a vs b carburator
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10-27-2014, 01:45 AM | #7 |
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Re: Model a vs b carburator
In the old days, every body knew that: (pi r square) was used to find the areas of a circle.
Today with modern math, pies are round & not square; so nobody can find the area of a circle or even imagine a 17 trillion dollar loan with nobody paying for it. We really have a modern political agenda today to establish & maintain total dummies. What ever happened to arithmetic? The Model A carburetor & intake had a 1" diameter throat & the Model B had a 1-1/8" diameter throat. With (pie are round) in lieu of (pi r square), nobody with new math can calculate that this 1/8" larger diameter for a B carburetor is actually a 25% increase in area of fuel/air entering the combustion chamber. Wow! Arithmetic, what is that? |
10-27-2014, 06:37 AM | #8 |
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Re: Model a vs b carburator
No one mentioned that the B Zeniths float bowl is shaped differently and the float hinged on a different axis so that you don't get that annoying stumble sometimes when you stop quickly. That also is an advantage. Its just an improved design.
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10-27-2014, 07:50 AM | #9 | |
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Re: Model a vs b carburator
I imagine it climbs hills quite well! I was warned off the polishing also. No reason given. Just clean up any casting glitches and leave the surface a little rough. So I used the word "polish" kinda loosely! I've been wondering if a little reshaping of the top of the valve guide "tower". Would this improve the flow?
Since you're not taking much out of the manifold 1/32 - 1/16 the reamers probably work fine. Terry Quote:
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10-27-2014, 07:57 AM | #10 |
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Re: Model a vs b carburator
I run the B carb on the stock A intake,I get a better idle,thats about it.
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10-27-2014, 12:39 PM | #11 | |
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Re: Model a vs b carburator
Quote:
Purdy. |
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