Fuel System: external fuel pump actually needed?

[bosshoss61]

I'm into the wiring part of my car. The replacement harness has no lead for the electric 6 volt fuel pump attached to the tank. Is this something that was added to my 50 Champion for better fuel pressure? The flat 6 has an external fuel pump. Does the pump run all the time when the ignition is on?
This is one part of the car, I would like to get right......
Thanks
Rick

[63 R2 Hawk]

An electric fuel pump would have been something that was added to the car by a previous owner. It isn't really needed as long as the mechanical fuel pump is working fine, but it's nice to have if the car isn't driven often. Some people will wire the electric pump to a toggle or momentary switch to get fuel pumping when first starting after a long time of sitting. The switch gets turned off once the car is running. Note that this only works if the electric pump is a "flow through" type, i.e., the mechanical pump can still draw fluid through the elect. pump even if it is turned off, so you will have to determine if yours is a "flow through" style. Others will use the electric pump exclusively, removing the mechanical pump and blanking off the block where it mounts. My guess is you probably don't need the electric pump if all is well with the mech pump.

[41 Frank]

Studebakers never were originally equipped with an electric fuel pump. The pump your car has was added sometime in the past. I have my electric pumps wired through a momentary on switch as I use them only to prime the carb and to relieve vapor lock. If you wire it direct it should be done through a switch that cuts it off if there is no oil pressure, so it cuts off in case of an accident. This has been discussed here many times, do a search and you will find lots of info here.

[bosshoss61]

thank you
I did do the search and found a lot of info. But, it's hard to find out specifics when the thread title is not. I think the added pump will come out. I need to replace the rubber gas hose from the tank to the line anyway. I'll get the motor fuel pump to do it's job. I kinda understand the vapor lock, and don't want that to happen in my 10 hour drive. Other than freeing up the gas cap---is there another way to releive vapor lock?

[sweetolbob]

thank you
I did do the search and found a lot of info. But, it's hard to find out specifics when the thread title is not. I think the added pump will come out. I need to replace the rubber gas hose from the tank to the line anyway. I'll get the motor fuel pump to do it's job. I kinda understand the vapor lock, and don't want that to happen in my 10 hour drive. Other than freeing up the gas cap---is there another way to releive vapor lock?

Yup!!

Install an electric pump with a momentary switch.

Bob

[bosshoss61]

thanks,
I've got an electric pump under the car now. If the gas tank is in that negative pressure creating vapor lock before I start the car, wouldn't an electric pump only make things worse upon start up?

[55 56 PREZ 4D]

If you do a search you will find all kinds of ways people have found to eliminate vapor lock.
Most deal with ways to eliminate or redirect heat near the fuel system.
Spacers under the carburetor, sheet metal cooling fins on the fuel lines, sheet metal shield at fuel pump,
diesel in the gas tank, block off exhaust port through the intake manifold, fuel return line from fuel pump to tank, etc, etc, etc.
Some will swear that vapor lock has NEVER happened to them ?
But like sweetolbob wrote, the most effective way is to install an electric flow through pump with a momentary switch. Doesn't prevent it, just eliminates it when it happens.
When you experience the sputter and engine dying just flip the switch till fresh cooler gas gets to the carb, shut it off afterward and drive on.
Install a fuse at the power connection before the momentary switch.

[sweetolbob]

thanks,
I've got an electric pump under the car now. If the gas tank is in that negative pressure creating vapor lock before I start the car, wouldn't an electric pump only make things worse upon start up?

I believe in the previous post you stated you were going to remove the electric pump. My answer may have been somewhat in cheek but the fact remains that with todays fuels that are engineered to perform in injection systems under 60 PSI or so pressures there is little one can do in the way of reducing vapor lock other than a pusher pump. There are all kinds of old fixes, like adding diesel fuel or kerosene or cloths pins to the gas line but the fact remains that today fuel contain a significant amount of highly volatile components and theoretically adding a high boiler can mitigate that but in real life there will still be a significant component of volatile and you can't add enough high boiler to bring the fuel back to what it was like when your car was new.

So realistically adding the electric pump, that you proposed to remove, is the only really effective way to help avoid vapor lock.

Lastly, your tank is vented or you would pull a vacuum on it when driving so startup with an electric pump is a non-factor.

JMHO

Bob

[bosshoss61]

Thanks for the replies---it appears that because of the higher octane unleaded gas (88-92) and the engine heat that increases pressure in the fuel line--- the car may vapor lock.
I have put the tank back in. Gas cap is not vented, it even has a gasket. And there is only one large 2-2 1/4" hose that connects the metal hose to rubber to tank. So where is it vented? I want to make sure it's clear. OH and the fuel pump is flo-through.....
Thank you
Rick

[showbizkid]

Rick, I think you're working with a false conception of what vapor lock is. It's not too much pressure in the fuel line - it's heat in the engine compartment that causes the fuel in the line adjacent to the mechanical fuel pump to boil, becoming vapor which can't be pumped.

Seriously, I'd leave the pump where it is and use it! As the guys above have said, rig up a momentary pushbutton switch to actuate the pump. If for nothing else than to prime the carb after the car has been sitting a few days, it'll be worth it. And if you ever do get into a vapor lock situation, the auxiliary fuel pump will help you get past it by pulling cool gas from the tank and forcing through the line, displacing the boiled gas and getting your car started again.

[Tom Bredehoft]

Another solution to vapor lock, Route a return line from the carb to the tank. Put a .030 restrictor in the return line, this will allow overpressure to return to the tank, making a continuous flow from the tank to the carb and back to the tank, keeping your fuel cool.

Venting the tank. Studebaker's answer to venting the tank was to put a breather through the cap. A 1/16 hole will do it, the gasket is to keep the cap from rattling, not breathing.

[kurtruk]

Since we're on the subject, your car originally came with a fuel pump heat shield. Many are tossed or lost when the fuel pump is replaced. SI offers replacements, part no. 527874.

[bosshoss61]

Thanks to all for your help...and thank you, "kurtruk". I have ordered the part. And am going to remove the electric pump(but save it for,,,lets call it future reference,,,,
thank you
Rick

[AnAvanti4Bob]

Are there any recommendations as to which Studebaker vendor sells the proper (flow through) electric fuel pump or are owners buying "off the shelf?" Car in question is a 1963 Avanti R1...thanks, Bob

[StudeRich]

"Most people" are not using electric Fuel Pumps, for one reason "most" drive 1955 to 1966 V-8 Models which have NO or very minimal, only in extreamly HOT conditions vapor lock issues. Not needed on Avantis with "cool fuel return line".

"Most people who have Electric Fuel Pumps", are getting them from Jeggs, Advance Auto Parts, Rock Auto Parts, or their local O'Reilly, NAPA, Car Quest etc.
S.I. does sell one type & Brand of pump, but as mentioned there are many types, some flow thru some not.