Using an electric fuel pump with a vacuum tank

I drove my '29 Packard Super 8 roadster on the Glidden Tour in Golden, Colorado in 2009. The car has the original vacuum tank, and it performed well. I only starved for fuel once -- after about a 10-mile 5,000-foot climb, with the throttle at or near full during much of that climb, running about 40 MPH. The car stalled so I pulled over and stopped. I pulled the choke out, put the car in reverse and coasted back a little and let out the clutch, and it started quickly and idled normally. Rather than keep climbing, I turned around. I really think I could have made the climb if I had let up on the gas a little, or just pulled over and let it idle a little. The overall performance was better than I thought it would be. Had no problems on steep 3-4 mile climbs at 40-50 MPH. I don't recall any climbs in northern New Mexico being as steep or long as those in the mountains west of Denver. I am thinking of taking the Packard on the New Mexico caravan.

Good point James. We used the 626 in the Adirondacks last Fall without any starvation problems, so you may well be correct in speculating that the climbs in NM won't be long enough to starve the vacuum tank. I lean toward sticking with the vacuum system. In my experience, electric fuel pumps can cause a problem as often as they correct one.

Things to keep in mind when driving old cars at high altitudes are loss of power and lower boiling point of water. Figure on a 3% loss of efficiency for every 1,000 feet above sea level. At 7,000 feet you are going to have a noticeable (20%+) loss of power. Water boils at about 190F at this altitude. This should not be a problem for cars with good functioning cooling systems. No real show stoppers, but things of which to be aware. I would like to participate if I can get some things fixed on my '47 Packard Custom Clipper. Hope to see you there.

Something else you may like to consider is a vac tank with a larger storage capacity, they were an option back in the day on some vehicles. In other words look for something to increase your holding capacity during those lengthy large throttle drive situations; come to think of it it might be just as easy to increase the capacity of your existing vac tank.

Mark - I installed one on my 1928 Overland Whippet. The Stewart Warner Vacuum pumps works very well and is my primary pump. I hid a electric pump inside the frame and it is difficult to spot unless you climb under the car. I have mine on a toggle switch and only use it on climbing high elevations on a long pull or when the tank runs dry. Very easy to throw that switch instead of taking the top off the tank. It does work through the tank without any problem. I only turn it on briefly because it will not shut off with the tank float.

Rick

That's the type of installation I was thinking about, Rick. Overflowing being a concern, I'd thought of using a momentary (starter-type) switch to run the pump. It's possible to refill the Stewart tank by pouring fuel through the plug on the top, but an electric pump would be a convenience-- especially if we're stopped along the roadside.

hchris, switching to a vac tank with a greater storage capacity is an interesting option, but I've never seen anything available that's larger than the one currently in my Packard. There's really not enough room on the firewall to accommodate a longer tank , so I don't believe lengthening the stock unit would be feasible. Any other modification is going to be substantially more difficult to accomplish.

Have a fire extinguisher handy

The vacuum pumps ,when right are great,we run all our cars on vacuum pumps,if it does not work ,not right,call us

I endorse Stude8's comments, although I have been running cars with vacuum tanks without an auxiliary pump for over 30 years and have never experienced the need for a pump because the vacuum tank failed to draw fuel from the tank. However I have often experienced vapor lock where an electric pump would have overcome the problem providing it fed directly into the carburetor as shown on the sketch from Stude8. If the pump fed to the vac tank then it is unlikely to overcome vapor lock. From my experience if you don't drive in hot weather then you are unlikely to suffer vapor lock and don't need an electric pump - if your vac tank is working OK

I have always replaced the pot metal tops with reproduction brass or aluminum units because as Stude8 said the originals can crack or worse allow the small brass valve seat inserts to become loose and leak. When this happens it is not obvious and much time can be wasted trying to find out why the tank will not pull a vaccum.

New tops are available on line from an Australian supplier, I can supply details if necessary.

Pumping through the vac tank is looking for disaster for sure,,If essential,,go for a electric system,,as bypass,,totally independent,,but it can also vaporlock,,,perhaps include a bleed back to tank to prevent temp buildup,,,,

I think running full throttle for extended time is pushing the limit,,,,the old chauffeurs would not do this,,,drop a gear and proceed,,

On the 29 Packard,,,fit a 31--4 speed,,,oh yes and block the shutters open to take any advantage,,,,and at top of hill face it into the wind and idle till the temp is stableized,,,,there will be a buildup of heat when the fan and waterpump stop suddenly when you park,,

With practice you can doubble clutch to 3rd about 40-45 mph,,Hold throttle about 1/2 way and pump the pedal 2x as you toss the gear lever,,If you drive min of 100+ miles per day,,,youll get the hang of it,,,Be sure to use the heavy steam cyl oil in the tranny,,and take out the gear lever every 10,000 mi and put oil in the throut bearing cup,,,the bijur thingie never seemed to get that far,,,oh,,memoriesCheers Ben ps,,dont forget all the heat is on the rt side of the car,,,CB

Hi. I have installed a Carter electric pump they are rotory and ok with ethanol. You have to install a check valve to have vac tank pump thru. I installed a old style horn button ,from napa, this way you can not forget and over flow the vac tank. Its there as a back up and I only have used it in the spring to fill the tank and carb. hope this helps. If you need more imformation call me 8608060448

I too have installed an inline electric fuel pump before the vacuum tank and only use it in an emergency to refill vacuum tank so use a momentary sw so that the vacuum tank does not overflow. I also use a bit of ATF in gas as it keeps the electric fuel pump from seizing and is also good for the rest of fuel system, Good luck