The Ford Barn

Terry, NJ · 06-29-2013, 05:32 PM

I was fitutzin' with a couple of Mod B carbs today, wondering just what could be done with it and I decided to measure the venturis. The one marked 22 and D-7691 measured .860 and the one marked .860 and 5 measured .867-8 or roughly .008 larger. The one to use, naturally! But I can't help wondering what if I took say .020 or .030 out of it would it reduce the speed of the air going through and actually choke it? as a pilot I'm familiar with Bernoulli's princible of air speed (Basically when the airflow is choked then the flow speeds up) As wing shape and profiles have changed sine 1930 , How about Carb venturis as well?
Terry

pat in Santa Cruz · 06-29-2013, 08:22 PM

I seem to remember reading that the smaller venturi carb was sold as a replacement for Model A engines.

see the reprint of the B carb sheet on this page:
http://www.fordgarage.com/
click to open Carburetors, Intakes and Fuel Systems
then click Zenith Carburetors, Model B
a pic of an old B carb advertisement will show on the right side which explains the 2 venturis

Bruce Lancaster · 07-01-2013, 12:23 PM

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Their were large ones, too...note the 26 venturi in the chart Vince provided! I actually found one...I started buying some of the junk B variant carbs that turn up at the fleas.
There are endless variants of these, generally lacking the Ford GAV and having several rearrangements of the fuel passages and many different linkage arrangements. I assume they are from industrial engines or something...one of them turned out to contain a 26.

06-29-2013, 05:32 PM	#1
Terry, NJ Senior Member Join Date: May 2010 Location: Bucks Co, Pa Posts: 3,740	Mod. B Carb. Esoteric stuff I was fitutzin' with a couple of Mod B carbs today, wondering just what could be done with it and I decided to measure the venturis. The one marked 22 and D-7691 measured .860 and the one marked .860 and 5 measured .867-8 or roughly .008 larger. The one to use, naturally! But I can't help wondering what if I took say .020 or .030 out of it would it reduce the speed of the air going through and actually choke it? as a pilot I'm familiar with Bernoulli's princible of air speed (Basically when the airflow is choked then the flow speeds up) As wing shape and profiles have changed sine 1930 , How about Carb venturis as well? Terry

06-29-2013, 08:22 PM	#2
pat in Santa Cruz Senior Member Join Date: May 2010 Location: santa cruz, calif Posts: 2,011	Re: Mod. B Carb. Esoteric stuff I seem to remember reading that the smaller venturi carb was sold as a replacement for Model A engines. see the reprint of the B carb sheet on this page: http://www.fordgarage.com/ click to open Carburetors, Intakes and Fuel Systems then click Zenith Carburetors, Model B a pic of an old B carb advertisement will show on the right side which explains the 2 venturis Last edited by pat in Santa Cruz; 06-30-2013 at 01:29 AM.

07-01-2013, 12:23 PM	#3
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: Mod. B Carb. Esoteric stuff Sponsored Links (Register now to hide all advertisements) Their were large ones, too...note the 26 venturi in the chart Vince provided! I actually found one...I started buying some of the junk B variant carbs that turn up at the fleas. There are endless variants of these, generally lacking the Ford GAV and having several rearrangements of the fuel passages and many different linkage arrangements. I assume they are from industrial engines or something...one of them turned out to contain a 26.