Downdraft Carb suggestions

[Charlie Stephens]

Originally Posted by racer32

Is there a quick way to ID the B manifold? Headed to a swap meet today.

Here are a couple of pictures in response to your request. Note large vacuum attachment boss is in front of early manifold.

Charlie Stephens

[john in illinois]

I have a new English 97 on a heated Charley Yapp manifold. It runs noticeably smoother than the Zenith. Used an air/fuel meter to check jetting. smaller jets were too lean,stock jetting was just right.

It is a little touchy to start hot. I think I will try a heat insulator betweeen carb and manifold.

Air filter in pic is too restrictive. A 4" tall K&N works good.

[Art Bjornestad]

I use an electric fuel shut off valve o a pair of 81's......keeps the "forget" part out.

[Purdy Swoft]

Originally Posted by Tiny

Thats a really neat setup. Who cares if you cant make photobucket work, if you can make two B carbs work!

For Photobucket I always use the IMG link by the way, never had a problem

I'm back on photo bucket, here is a better pic of the Trojan setup.This is how it looks now on the finished roadster. I've got one more.

[Purdy Swoft]

different angle

[gwhite]

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A Winfield S/SR would be a good period option.

[JtownJoe]

I also can vouch for the Weber set up. It was difficult to get the right throttle linkage travel range, either not fully opening or too fast at idle, but discovered some play in the two piece shaft & spring on my stock accelerator linkage but once corrected it runs very well and no longer has the constant gasoline in my attached garage. Only complaint is the chrome air cleaner supplied with it, looks tacky to me.

[BILL WILLIAMSON]

Originally Posted by JtownJoe

I also can vouch for the Weber set up. It was difficult to get the right throttle linkage travel range, either not fully opening or too fast at idle, but discovered some play in the two piece shaft & spring on my stock accelerator linkage but once corrected it runs very well and no longer has the constant gasoline in my attached garage. Only complaint is the chrome air cleaner supplied with it, looks tacky to me.

Whut's wrong with my air cleaner? I liked it! Minerva ran 80 MPH, once only! And the pizza stayed HOT by the exhaust heater
Bill W.

[Jordan]

I had a weber on my car, then I was convinced to put a stromberg on there. That was on it all summer. It was way more sensitive in pedal reaction and acceleration, but I didn't like it on the top end of cruising. It also seemed to run differently with every tank of gas. I switched back to the weber that never gave me a problem.

[Jim Brierley]

Brent, When I bought my early '30 tudor several years ago it had a stock "B" engine in it, with "A" manifolds and carb. I ran this for a very short while but during that time the Auburn hill climb was being held twice a year. At one climb I ran it "stock", meaning as I bought it. For the next climb a few months later I had installed a Winfield 6:1 head, the times improved by a full second. That same day I installed an 81 on a Burns manifold, the times improved by another full second. For the next meet I had a 97 on the same manifold, and it picked up another 3/10 of a second. These were all averages of 2 or 3 runs. Shortly after that I came back to my normal self and put an early Miller under the hood. So for me, a stock B engine is as close to stock as I ever came, you caught me!

[racer32]

Feel free to send me all those crummy old Strombergs!

[denis4x4]

Originally Posted by Tom Endy

A club member recently told the membership about his misfortune with a downdraft carburetor. His Model A is equipped with a downdraft manifold, downdraft carburetor, and an electric fuel pump. His thinking was that the fuel pump would block any fuel flow from the tank to the carburetor when the engine was shut off, therefore there was no need to shut off the tank valve. Wrong assumption.

He had not driven the car for about three weeks, when he went to do so he found that about four gallons of fuel had flowed into the intake manifold and into the engine, including the oil pan.

His advice is to always shut the tank valve off. One would also hope that the tank valve has the ability to shut off 100%.

Tom Endy

If the electric fuel pump is wired into the ignition circuit, how can it pump four gallons on gas into the intake if the car is turned off? Another reason for a battery switch.

[BILL WILLIAMSON]

Gravity flow can push fuel through a fuel pump & it must have had a funky needle/seat & slowly dribbled gas into the manifold & cylinders & leaked past the rings into the pan. Bill W.

[Juggler]

Originally Posted by john in illinois

I have a new English 97 on a heated Charley Yapp manifold. It runs noticeably smoother than the Zenith. Used an air/fuel meter to check jetting. smaller jets were too lean,stock jetting was just right.

It is a little touchy to start hot. I think I will try a heat insulator betweeen carb and manifold.

Air filter in pic is too restrictive. A 4" tall K&N works good.

I have the same setup

A phenolic spacer twixt carb and manifold fixed it

As you say, stock jets have worked for me.

[Tom Endy]

Originally Posted by denis4x4

If the electric fuel pump is wired into the ignition circuit, how can it pump four gallons on gas into the intake if the car is turned off? Another reason for a battery switch.

You cannot wire an electric fuel pump to the ignition circuit in a Model A with a stock ignition set up. If you do you will have the pump in series with the coil and parallel with the points and the engine won't run.

The fuel pump did not pump fuel into the engine because it was shut off. The fuel fed by gravity from the tank past the stationary fuel pump into the down draft carburetor then leaked past the float valve in the carburetor and into the intake manifold. From there it was all down hill into the engine.

An electrical shut off would not have anything to do with the situation. What was needed was for the owner to shut off the fuel valve under the tank and hope it had the ability to shut off 100%.

This type of leakage does not happen on a Model A equipped with the updraft carburetor Henry delivered with the car. The updraft carburetor sits below the manifold and valve ports. Fuel leaking past the float valve in the carburetor ends up on the garage floor not inside the engine.

Tom Endy

[denis4x4]

Tom, thank you for your explanation. Even though my Model A engines are not stock, i do use the stock fuel tank shut off on the '29 CCPU.

[John LaVoy]

The Weber works very well. We have it on the sedan and the roadster pickup. Tom's warning is correct for the shut off. Arizona Model A is a great source for the whole package to install the Weber. 480-782-0266 www.arizonamodela.com

[hotrodalley]

Holley 92

I am replacing my Weber with a Holley 92 on a vintage Burns Intake. The Weber is a good setup, but I just cant get used to the "modern" look. In addition, i am replacing the stock head with a hi compression Cyclone head. The engine is stock rabbit. Hope it all works. I know I will have some plumbing design to do for the fuel line and electric pump. I have an indented firewall so mounting a pump on the inside of the firewall is not an option. Holly 92's are a little difficult to find, but I have run them in tandem on a hopped up banger and they are great. I assume a single 92 on a pretty stock motor will be ok.

[john in illinois]

Originally Posted by Juggler

I have the same setup

A phenolic spacer twixt carb and manifold fixed it

As you say, stock jets have worked for me.

Thanks for the feedback,I will try it.

John