VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Fuel Pump options

I am having an issue with my engine staying running and I think it may be a fuel supply problem. How do I verify this for sure? Can I run out of a temporary fuel container gravity feeding into the carb? If my vacuum pump is the culprit can it be bypassed with an electric pump? If so, what is the best pump to use and how many psi should I require? I know the edelbrock on my hot rod I used to have needed 4 psi, but it wasn't gravity fed either. I don't want to overpower the needle and seat. Has anybody else done this? What have you used? I really want to get this truck driveable!

Thanks.

I put an electric fuel pump on a 26 Chevrolet Fire Truck. I used a regulator from NAPA made in the USA and had no problems. The first two I tried from one of the other chains made in China only worked about 30 minutes. They looked the same except for the writing on the outside that said made in USA.

You can set up a separate gravity feed fuel source to find the guilty party.

The use of an electric fuel pump is discouraged. Your best bet is to repair the vacuum pump so it has a fighting chance to solve the problem. Two things I know about the vacuum pump, it will run 7 miles from full to empty, and the second thing is that a good pump will take you to the top of Pikes Peak, because I have proven it with my 1925 Roadster sitting, on top by the stone marker.

I agree with Antique Mechanic, Vac Tanks are good once you have them set up right. In 35 years I have only had one problem, caused by me, when as a green horn I put silastic around the top gasket. major no no. Learnt my lesson, no problems since. Over the years a few guys have asked me regarding converting to a pump. In all cases after we worked on the vac tank and got it going, all are still running vac tank.And as mentioned if all fails on the road, you have a mini grvity feed tank.

Hang in there

Cheers

Ray

How do I know if it is working correctly? I drained it the other night to inspect all lines and fittings for flow and it had about a full 32 ounces in it. I also know that it pulls fuel from the tank because I have had to put fuel in it twice now. What alas could cause it to run out of fuel and die?

Let's point a finger at the carburetor, particularly the float.

Have you tried the separate fuel supply from a container straight into the carb?

yes dont assume iT is the vacuum tank, i have the late 28 Stewart vacuum pump on my 28 chev ute AND EVEN AT 60MPH YES 60MPH IT DOES NOT HAVE PROBLEM. In the owners hand book it says some thing about flow from the vacuum tank being a pint a minute from memory.RAY

I have not tried a separate container. I currently am in the process of pulling the trans to fix a clutch issue and cant run the engine. I am hoping to wrap that up this week and will be working on the running problem right after that. I am hesitant to blame the carb because I just had it rebuilt by Chipper.

If the vacuum tank has fuel in it and the fuel level in the gas tank keeps dropping that should mean that the vacuum tank is working, right?

Yes, that should prove that it is getting fuel to the carburetor.

Perhaps some debris has gotten into the carburetor. We still can't eliminate an electrical problem.

When you get the clutch taken care of come on back here and we will work with you on the problem.

If you want a nightmare put an electric pump on it. Nothing but trouble and I have ripped every one off every car I own and happily tossed them into the trash. Every electric pump on an old car I have ever owned has left me sitting on the side of the road broke down. Test the vac tank vac fitting for good vacuum. check fuel flow from the gas tank to the vac tank fitting first, then to the carb from vac tank. if good flow it is narrowed down to carb or vac tank. Then test carb with a gas can siphoning gas to the carb inlet. If car keeps running the look at the vac tank. Take it apart and clean everything! the inner tank has a small flapper valve and make sure it is clean. Check float for leaks. Check vent hole at bottom of one of the brass fittings on top and make sure it isn't clogged.

I installed an AC 6 volt electric fuel pump on my 28 near the tank, mounted it on the frame and installed a MON ON toggle switch under the dash. It has never been needed on the road because the vacuum pump is in good condition, I was afraid that climbing a long hill it would not have enough vacuum at a high RPM in second gear, however it never faltered. I have used the fuel pump to check for clean fuel before it get's to the vacuum pump. I have an old Delco settleing bowl ceramic filter mounted on the firewall and I can remove the glass bowl, run the electric pump with a gallon bucket under the filter housing and to fill the glass bown when I clean the settleing bowl. The AC electric is a fuel pump that fuel will flow thru when it is off.

One of our club members did have a problem with the same pump and same installation in his 28 when he filled up with some 85-15% ethonol gasoline and it sat in the tank for several months. It ate all the rubber in the pump up and plugged the fuel lines,vacuum tank, and the carb. I will probably remove the electric pump on my 28 if it ever fouls up, so far it is ok with Central Texas gasoline. Just ot be safe, when I stored the car I added a can of Seafoam to the tank and ran the car a few miles. That has worked for me before, I don't use any Stabil.

I agree re fuel pumps, I had one on my 28 coach when I imported it and it always played up. After fixing the vac tank, it ran well for over 20.000 miles and then the float cracked and sank. I fitted a new on and it never let me down.
Now I'll frighten all you bods who use a fuel pump. It's hard to get the pressure down with these and a mate was running his pressure a bit high, 5 lbs from memory and the needle and seat failed and fuel somehow splashed on the plug ends and woof up it went in smoke, fortunately he had a fire extinguisher with him and saved the Chev albeit badly scorched, about 7k to fix.
Chris

Those that have tried an electric fuel pump and had problem's with to high of preasure and wrecking there fuel system, would it not be wize to install a psi adjustable fuel regulator 0-14 psi with a lower flow rate fuel filter??? would this work???
I have the old vac system and was thinking of a electric pump as a back up if the vac system ever failed while out on the road.
The reason I ask is that when I restored my vac pump, the small springs inside that control the valves where so brittle they crumbled, but with luck I had another set but they to seem brittle ,but with care I got them in.
Where could one find new springs for the Stewart Warner vac pump???


Keeping vintage Chevy alive.

Are you talking about the two long springs?

The problem with the pressure regulator is that they can't produce the low pressure we need reliably. Consider that all we are producing is the pressure generated by having the vacuum tank just a few inches above the carburetor. Now figure what pressure that would be. Less than you can lower the pressure in a pressure regulator and be consistent.

Yes the two long springs that control the levers.


Keeping vintage Chevy alive

Why do you need a back up for a vac tank if its set up right in the beginning. At worse if it breaks down you can drive for many miles on a full vac tank converted to a gravity feed fuel tank.

Do you have a spare fuel pump in your modern car as well?

I think a lot of people have a small problem with their vac tank, throw their hands in the air and install a fuel pump.

If you spent the same amount of time restoring your vac tank as you would installing a fuel pump and associated bits, you would never have a problem again.

In my case only one drama in 35 years when I used silicone in error.

Good luck in what ever direction you take.

Regards

Ray

Most people, even trained mechanics, are not familiar with 1928 fuel systems so advise using a modern pump to replace that ancient and "unreliable" (in their opinion) system. What they don't know is there are no gaskets, diaphragms or other elastomeric (say rubber) materials to swell up or disintegrate when ethanol is present. They also don't understand how you can get enough gas flow with less than 5 psi pressure at the carburetor needle valve. Just because people don't understand or are familiar with the systems in our old cars does not mean that they have not worked well for 80+ years. Stuff and people who have functioned well for 80 years should be revered not replaced, IMHO! Mechanical brakes is another example!!!!!

My trained mechanic isn't even familiar with rebuilding and/or tuning a carburetor! No kidding. Knows his stuff on the modern computer controlled stuff though...

Contact Gary Wallace for your vacuum tank springs. chev4cyl@charter.net

On my 28 coach and my 21 490, both cars had previously been worked on by young shop mechanics who messed up things on both cars. The one who worked on the 21 was a certified aircraft mechanic who couldn't set points and put a battery in with the wrong polarity. The guy who worked on the 28 before I bought it,put in a new US made electric fuel pump (which failed after only 50 miles), wrong light bulbs, wrong size gauge battery ground cable,wrong gauge wires for the headlights, couldn't figure out how the original ignition switch worked and a whole lot more. Best thing you could do is keep those guys away from the truck and get the owners manual and service books and read them thoroghly. Read them several times if you have to and forget everything you know that applys to modern cars when working on it. These old timers are so simple and being so simple they avoid a lot of the headaches that overcomplicated machines have. That is the true beauty of them!

...Bob I am just as bad with the modern stuff, I looked for a distributor for quite a while on my daughter's late model Chevy 4 cylinder crosswise engine...never did find the distributor, it must have been somewhere down behind the engine where the light never shines............after I found the #2 sparkplug out of the sparkplug hole and screwed it back where it belonged the car ran and that terriable noise stopped!
"Give me that old time religion!, it's good enough for me" ....I mean automobiles!..."See the US..A in your Rusty Chev...rolet!!!! Da Ta Da"

Hello,
I had my vac tank repaired 27 years ago and it is still going fine.No need for electric fuel pumps as all they do is create fires.Seen a 1929 chev catch on fire from a electric pump.

Only thing I have done is install a rubber fuel primer from a outboard boat fuel tank just under the front floor on the fuel line before it enters the vac tank.It is real handy for priming the vac tank if it has been sitting for a while or I forgot to turn the tap off and the tank is empty.Just a few squeezes and the tank is full ready to go.

This has been an interesting thread with good information on both sides. I have a '24 Touring that had a 6 volt electric fuel pump on it when acquired. It is a NAPA. When I finally got the car running I had too much fuel pressure (6psi). Used 1/2 of a hot rod duel carb pressure regulator to cut the fuel pressure to 1 1/2 psi and it has worked fine since. I have the restoration of my vacuum system on my "to do" list. The information provided by all is appreciated.

Bill Rigdon '24 Superior Touring

Hey Rusted,

I run an out board primer also. Have never had to use it as a primer, and the added bonus is the one way valve that keeps the fuel line from draining back when the vacum is off.

Regards

Ray

My vac tank has the original shut off valve on it. I turn it off when it will sit for a while since some gas will evaporate out of the carb or slowly drip out of a not totally perfect needle valve. The kicker is you have to remember to turn it back on! (don't ask)