Electric fuel pumps

[Larry Schramm]

8 hours ago, edinmass said:

 

Look up the definition of the word stoichiometry.............Duesenbergs used electric pumps in the tank in 1930..........Stewart Warner six volt sealed units. 

 

Ideal stoichiometric ratio for a modern gas engine is 14.7:1, air to fuel.

Edited August 4, 2023 by Larry Schramm (see edit history)

[Morgan Wright]

On 8/3/2023 at 12:53 PM, 28Buick said:

Apollo 13. Technically not a modern car, but a modern space craft designed with the best technology available at the time. 

 

Apollo 13 had oxygen tanks

[28Buick]

Thanks again to Hugh for outstanding advice. Just returned from France and my 5/16 copper tubing and straight couplers were waiting to fix the fractured fuel line. I decided to buy a fine mesh VW fuel tank screen instead of making my own, it soldered nicely as shown. I'm working from the fuel tank forward. Next step is to clean and rebuild the vacuum tank.

Edited August 31, 2023 by 28Buick (see edit history)

[EmTee]

That VW filter sock is perfect - I'll have to remember that one! 

[Brian_Heil]

Try these sealing washers:

 

 

[28Buick]

Appreciate the good advice, I purchased a set of the aluminum/rubber crush washers that might come in handy when attaching the banjo to the relatively weak pot metal vacuum tank cover.

[28Buick]

Just for a visual record here are some banjo fitting washer options. In this picture left to right:

1-What was removed, 2- Solid copper crush washer kit via Amazon; 3- Hollow copper crush rings in rebuild kit from Bobs Automobilia; 4- Autohaux via Amazon as recommended by Brian.

I will likely use set 4 in the quest to achieve an airtight vacuum fuel system.

[Brian_Heil]

Pre lube the washers and be gentle. The lids are fragile and known to crack

[Grimy]

1 hour ago, Brian_Heil said:

Pre lube the washers and be gentle. The lids are fragile and known to crack

Be gentle especially on the fuel fitting/banjo lest you crack/split the pot metal "tower" into which it is screwed.  As for the circumferential filister head screws, if judging is not in your immediate future add a flat washer under each to spread the load.

[28Buick]

1st Pic: Opened the vacuum tank and discovered it was full of fine rust particles. The inner and outer tanks were not pitted but extensively coated in rust dust. Removed all the loose rust with a 3M scotch brite; there was about three times the dust you see on the white cardboard in the first picture. This crap was likely to clog filters or worse yet the Marvel.

 

2nd Pic: To prevent further oxidation, both the inner and outer tanks were coated with POR metal prep to bond the rust then coated with POR fuel tank sealer. The outside got Rustoleum black. Followed the PDF instructions from Hugh to ensure the tank was working properly.

 

3rd Pic: Tank attached with the banjo sealing washers mentioned by Brian. I used stainless flat washers under the screws and they are hardly visible. Fuel delivery is now working great. Drove it about two miles and the antifreeze started to steam. Next on the to-do list is a cooling system diagnosis.

[28Buick]

IR shows 170 degrees F at the top just under the coolant return hose, and 165 degrees F at the bottom center of the radiator, both temps recorded on the fan side. Front side thermal image below shows same thermal gradient top to bottom, and what might be an obstruction inside the radiator behind the 9-3 on the license plate. I read somewhere on this forum that a 20 degree F drop top to bottom on the radiator is optimal. Suggestions on what to do are welcome. I plan to remove the radiator to backflush it upside down, and purchased a few gallons of Evaporust ER012. Apologies for drifting from the OP topic of electric fuel pumps so more on this cooling system venture may be in a different thread in this forum. Happy labor day week.

[Eddie-O]

Just curious about the electric 6 V pump you can get at Bob’s or other sources. If one is used only as an easy way to start the car after sitting for long periods without having to prime the carb or crank the starter to an inch of it’s life, or during a vapor lock moment, is there a down side to this? Just turn it on after a long periods of sitting idle and shut it down once the car starts would seem ideal I would think. Right or wrong?

[edinmass]

Electric pumps on cars with a vacuum tank is begging for a fire……….a big one.

[Morgan Wright]

2 hours ago, edinmass said:

Electric pumps on cars with a vacuum tank is begging for a fire……….a big one.

 

Vacuum tanks work fine. If it ain't broke, fix it till it is.

[Mark Shaw]

Just my opinion from years of experience:  If you choose to use a solenoid pump, buy two so you have a spare to replace the first one that will eventually fail. 

I use a rotary electric fuel pump in my 1931 Buick because the pump push rod guide is broken in my engine.  Rotary pumps are inherently more reliable and run more quietly than solenoid pumps.   

This is the pump I use except that mine is a 6V model:

Amazon.com: Carter Fuel Systems Electrical Fuel Pump Automotive Replacement 12V (P4594) : Automotive

Edited September 17, 2023 by Mark Shaw (see edit history)

[nat]

     Electric fuel pumps on an updraft carburetor are an accident waiting to happen but provide years of entertaining debate on every forum.

[Morgan Wright]

Has anybody ever concocted an idea of an electric fuel pump pumping fuel into the vacuum tank, and a return line letting the overflow drain back to the gas tank? This way the electric pump is on all the time, never shuts off and just fills to the overflow line and the excess returns to the gas tank, no valves or switches of any kind, and the carburetor is still gravity fed from the vacuum tank with zero pressure to the carb. 

[nat]

7 minutes ago, Morgan Wright said:

Has anybody ever concocted an idea of an electric fuel pump pumping fuel into the vacuum tank, and a return line letting the overflow drain back to the gas tank? This way the electric pump is on all the time, never shuts off and just fills to the overflow line and the excess returns to the gas tank, no valves or switches of any kind, and the carburetor is still gravity fed from the vacuum tank with zero pressure to the carb. 

     That would work providing that there is a big ass return line and/or a scavenge pump but it seems more complicated than reseating a leaky valve or two.

     A slurry of abrasive cleaner such as "Ajax" or "Comet" works well as a fine lapping compound.  Valve lapping compound is too coarse for fuel valves.

[Hubert_25-25]

Keep in mind that the vacuum tank is not a positive shut off device.  There is no needle and seat inside on the fuel system like a float bowl.  The opertion is based on sealing the vapor space so that engine vacuum can draw fuel in, and then venting that vapor space to allow the fuel to be drawn out.  The large float inside is only used to toggle the vacuum and venting on the vapor space. 

So unlike a carburetor bowl that maintains a fuel level in a narrow band, the vacuum tank manages the fuel level in a much wider vertical level distance. 

 

I always keep a can of starting fluid under the front seat (for emergencies) and one near the car.  Sometimes if the car has been sitting for a while, I will give it a shot in the carburetor to ensure I have fuel for starting.  My fuel line is all copper between the gas tank and the vacuum tank, and I find this safer than having an electric pump with rubber hoses and hose clamps in the fuel line. 

 

One of the sticking points about a car with a vacuum tank that sits for extended periods is evaporation of the fuel.  To achieve maximum vacuum for filling the vacuum tank, the throttle or choke must be closed so the engine vacuum draws fuel thru the tiny hose to the vacuum tank.  You want a slightly richer mixture when starting the car from cold, but pushing on the gas pedal opens the throttle which would have a tendency to lower the vacuum while cranking.  That is where the choke helps.  When using starting fluid, I spray it into an open carburetor, then close the choke to trap some vapor inside the carburetor for starting as it evaporates rapidly.  I try to crank the engine as quickly as possible after spraying.     Hugh    

    

[Eddie-O]

On 9/16/2023 at 12:04 PM, Mark Shaw said:

Just my opinion from years of experience:  If you choose to use a solenoid pump, buy two so you have a spare to replace the first one that will eventually fail. 

I use a rotary electric fuel pump in my 1931 Buick because the pump push rod guide is broken in my engine.  Rotary pumps are inherently more reliable and run more quietly than solenoid pumps.   

This is the pump I use except that mine is a 6V model:

Amazon.com: Carter Fuel Systems Electrical Fuel Pump Automotive Replacement 12V (P4594) : Automotive

Mark,

I called Carter to inquire about the type of pump you have and if it would work for only starting after long idle periods and could then be shut off and the car run on it’s vacuum pump as designed with an on off switch. This is for my 41 special 248, but Carter tells me they don’t make a 6 volt and would not work the way I’m looking for. Any ideas? Thanks.

 

[Lee H]

Carter does make a 6v version of that pump. P/N P-4259. 
https://www.amazon.com/Carter-P4259-Line-Electric-Fuel/dp/B000CIS4IU/ref=sr_1_2?crid=39MYPY7UYLOSK&keywords=p4259+fuel+pump&qid=1695046137&sprefix=P4259%2Caps%2C698&sr=8-2

I would counsel you to also buy their noise isolation kit. They can be a bit loud if not intelligently mounted.

[Mark Shaw]

1 hour ago, Eddie-O said:

Mark,

I called Carter to inquire about the type of pump you have and if it would work for only starting after long idle periods and could then be shut off and the car run on it’s vacuum pump as designed with an on off switch. This is for my 41 special 248, but Carter tells me they don’t make a 6 volt and would not work the way I’m looking for. Any ideas? Thanks.

Carter P4259 6 Volt Electric Fuel Pumps (speedwaymotors.com)

Evidently, you spoke to someone who doesn't know his products. 

Mine is on a switch just for starting and for hot days when vapor lock becomes an issue.  

 

Edited September 18, 2023 by Mark Shaw (see edit history)

[Mark Shaw]

1 hour ago, Lee H said:

I would counsel you to also buy their noise isolation kit. They can be a bit loud if not intelligently mounted.

My electric pump came with the rubber mounting assembly. 

I can still hear it run when priming the carb for starting. 

I cannot hear it with the engine running. 

[Lee H]

2 hours ago, Mark Shaw said:

My electric pump came with the rubber mounting assembly. 

I can still hear it run when priming the carb for starting. 

I cannot hear it with the engine running. 

They do come with rather small rubber grommets to mount the pump to the bracket, but to really reduce the noise transmission, they make larger rubber insulated studs to mount the bracket to the car. Hard to put in words, but roughly cut the noise in half.

https://www.amazon.com/Carter-18-14U-Fuel-Pump-Mounting/dp/B005GC5ZDO/ref=sr_1_1?crid=1D1KYAGCH9OHQ&keywords=Carter+18-14u&qid=1695058482&sprefix=carter+18-14u%2Caps%2C353&sr=8-1

[Eddie-O]

Thanks guys. Speedway has it in stock. One more question though. Would I need a regulator for my 41 248 with dual carbs or not? As I mentioned, it’s only for start ups and vapor lock if needed. The whole system is stock Buick. No issues except for long periods of sitting. Three weeks or loner. Again, “Thank You “

[DonMicheletti]

I use them without a regulator, for priming only, on both my two 1938 Buicks and have never had flooding issues.

[Eddie-O]

Great, thanks. Flooding was my main concern.

[EmTee]

I can hear the sound of my pump change once the float bowl is full, then i turn it off.