Re: 1930Vacuum Tank Blues

Posted by Owen_Dyneto On 2010/5/24 10:49:28

The float & needle/seat arrangement in updrafts is pretty much limited to about 0.50 (1/2) psi because it's a gravity feed so I'd suggest the best solution is to have the vacuum tank repaired - from the folks I talk with that tour with vacuum tank cars routinely, they rarely if ever have problems except for a 1st start when the car has sat for a prolonged period of time. Folks who service S-W tanks are reasonably plentiful, browse Hemmings for a source, or send me a PM if you prefer. Also check for a tiny pin hole somewhere in the fuel link between the vacuum tank and the fuel tank - not an uncommon problem.

There are folks who have rigged electric pumps with a closed loop back to the gas tank and then tap off a small amount of the flow to the vacuum tank, but I don't hear any glowing reports about how well it copes with varying engine fuel demands at different speeds. And of course it presents or can present a serious fire hazard if the electric pump overwhelmes either the vacuum tank or the carburetor. Perhaps there is another solution out there but I'm not aware of it. A properly repaired vacuum tank with no leaks in the fuel line to the tank should perform extremely well.