fuel pressure to Model B carb?

johnbuckley

johnbuckley

Well-known member
What should be the fuel pressure to a Model B carb if using a fuel pump (mechanical or electric). ( and please don't just say "enough but not too much!!")
 
I believe a full Ford A gravity tank gives just slightly under 1 psi . So if one is using a B carb on an A with standard gravity feed tank should one add a pump to raise the pressure a bit?
 
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Pump probably not necessary.
Anecdotally, I ran a B carb on my '30 Murray for years without a problem.
Hope this helps.
Peace
 
Most will need a pump w/ 1 1/2 to 2 1/2 # about like a V8. Pumps are almost identiticle to a V8 pump. ken ct. OMO.
 
Generally speaking, you only need a pump when you use a downdraft carb. Even then you can use a 12 volt pump on a 6 volt system and it will work perfectly without a regulator.
 
I do not run a pump on my B carb which is in the stock position, just completed some 1500 miles of which some were very steep up & down, 120 kph on open highway, never needed a pump. However if you wish to run one 2psi would be plenty.
 
I run dual B carbs on two of my cars with no pump and they perform well. I don't use the float spring on my B carbs.
 
I was curious if its worth switch to a Model B carb on my A engine. Is there much performance improvement?
 
If everything is right and the intake runner is opened up to model B size you will gain a little top end. You won't feel the difference in the seat of your pants. If the engine has some mods like higher compression, better cam,port work, hotter ignition and free flowing exhaust, Two B carbs on a larger intake manifold will make more of a noticable improvement. When the high speed jets kick in on my speedster with dual B carbs, I can really feel the power

2085340-T600450.jpg
 
You guys have to remember 1 or 2 updrafts sit much lower on the engine and gas tank than 1 or 2 downdrafts which are up much higher. ken ct.
 
With my Weber downdraft, I still have about a 6" fall, which seems to be sufficient, even with a near empty tank. It was still running when I was able to put 10.695 gallons in the tank.
 
To pump fuel from the rear tank to the front tank, I used a regulator set at 2lbs on o zenith or tillotson.... I don't remember. We all had additional tanks on the World Tour.
Bruce Davis
a400usa@nccn.net
 
Skryla, I just got my '31 on the road and it is running a diamond block B motor with dual 81's. I'm running the stock B fuel pump and have had no problems with fuel delivery.
 
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