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Greetings All,

My vacuum tank may be starting to fail and am wondering if anyone has found someone who can rebuild them or if anyone has tried using an electric fuel pump to push the gas into the vacuum tank.

Would the vacuum tank if it is working draw the fuel through the pump when off, as the electric one on my '56 does, or would the pump have to be on all the time and will this cause the tank to overfill and possibly flood the carb.

Thanks
Gene

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.

We have rigged an electric fuel pump that is hidden inside the gutted vacuum tank. It was done by someone else, so I have no idea regarding the mechanics of the operation. The car is driven quite extensively, so I know it works.

There must be a pressure regulator in there to keep it from flooding the carb.

Kev, are you aware of a pressure regulator that will throttle down to about 1/2 psi, or even perhaps a bit less?

Eugene - what is the problem? i just did extentive work on my 29's fuel system maybe i can help. if it is not drawing fuel from the fuel tank check the supply line for a hole or dent caused by a stone or other road debris.

Dave

Quote:
Hmmm. Now I'm really wondering how it works. Unfortunately, the man who restored the car has now passed away, so unless I open it up to inspect, it's going to be a shrouded secret... that is, until it fails.

I happen to have a vacuum tank that I think fits your car. Send a PM my way or just e-mail me at dbaird@semo.edu and I can compare and let you know.

Vacuum tanks actually work well and the Packard style is the best as it has a prime fitting on the top (should you loose prime).

Use a cork gasket - paper will let you down every time; and holes for screws should be snug against the screw shaft - ie do not use a paper hole punch just because it makes a hole that is close - you really need an exact size hole. Also pipe fittings need to be tight (but they are fragile so do not overtighten) and top of tank bolts need to be snug (overtighten and you will warp lid - it is just die cast and very fragile. Equally, you also need to shut the gas off at the bowl when the car is parked for any more than a few hours.

Things tend to go south as far as maintaining prime after a few months, but a help is to Use Stabill in your gas as a preservative.

I wrap my gasoline lines in old fashion braided electrical wire wrap and wrap the exhaust pipes from and from manifold to front floor and to kick-up of rear axel to tail. remember, there was a time when the goal was to preheat the gasoline (thus why your exhaust almost wraps your gasoline tank).

Electric pumps and vacuum tanks are not a hand in hand thing and a good way to set your car on fire. Use one or the other. If you do go electric install a pressure regulator. I am not sure that 1/2 lb of pressure will supply the fuel bowl with the needed volumn of gas to drive at speed though. A 1930 carb is pretty primative as far as a needle and seat. I run the more advanced carbs (ex. 35 V-12 at 2.5 lbs). I run all the vacumn tank cars on original systems - and live w/such as just a nature of the beast pain the the ...