6V Electric Fuel Pump -maybe better than Carter 4259

[Bryan]

Started looking at electric fuel pumps since my dual headers are too close.  First thought the Carter 4259 was better, but at $74 on Amazon.  A little research found that Carter took over Airtex. You can see on Airtex model listing pump at the bottom has same # as Carter.  There is a lower psi Airtex pump 8902 that might be a better fit, since Stromberg literature implies 3psi is preferable pressure.

[James_Douglas]

If you go looking in my old thread you will find some stuff on these pumps. One thing is VERY important. They do not like to be run without fuel flowing through them. There is a specific amount of flow per hour that has to be maintained so the will not overheat.

 

The best thing to do is to put a "T" at the carburetor and a return line to the tank. Weld the "T" on the return side and drill a small hole, the size is in my old posts, which will allow for the proper flow so the pump never gets hot. Also, this help a lot with any hot day problems as in stop and go traffic the fuel is always cool at the carb input.

 

James

[Sam Buchanan]

I ran the Carter pump on a kit car for ten years and my Carter P15 installation is nearly two years old. In neither case did I use a return line and the pumps have been flawless. Neither installation had a regulator and there are no drivability problems.

 

I did, however, add a rubber isolator (radiator hose) to the pump in the '48 to cut down on noise being transmitted up into the body.

 

 

 

 

 

Edited December 15, 2021 by Sam Buchanan

[Bryan]

14 minutes ago, Sam Buchanan said:

I ran the Carter pump on a kit car for ten years and my Carter P15 installation is nearly two years old. In neither case did I use a return line and the pumps have been flawless. Neither installation had a regulator and there are no drivability problems.

 

I did, however, add a rubber isolator (radiator hose) to the pump in the '48 to cut down on noise being transmitted up into the body.

 

 

 

 

 

What's the steel line running over the pump? Looks large to be a brake line?

 

 

[Sam Buchanan]

The brass-colored tubing is new brake line. The other is clear plastic tubing containing the wires I added to get rear turn signals.

[Bryan]

I ordered the Airtex 8902 from Amazon.  Made by Carter, little less pressure.  Might put just a T somewhere to hook a gauge up to.   With psi line losses it should be about 3-4 psi when it gets to the carburetor.  Now to find or make a block off plate.   

[James_Douglas]

On 12/15/2021 at 11:07 AM, Sam Buchanan said:

I ran the Carter pump on a kit car for ten years and my Carter P15 installation is nearly two years old. In neither case did I use a return line and the pumps have been flawless. Neither installation had a regulator and there are no drivability problems.

 

I did, however, add a rubber isolator (radiator hose) to the pump in the '48 to cut down on noise being transmitted up into the body.

 

 

 

 

 

Yes, but how many times have you been stuck for an hour in 5 MPH stop and go traffic. How many 1 MPH parades. If you do, it will fail sooner or later,

 

The Carter engineer was quite clear. There is a minimum flow requirement for the motor to not burn up. The problem is that the flathead six does not use enough fuel at idle or close to it to hit that flow target.  He says about a dozen times a year they get people calling and complaining that the units burn up.

 

James

[Bryan]

Seems like 30 gph should be enough - whew!  What size fuel pump do I need? (summitracing.com) 

Wondering about line size.  What size fuel line do I need? (summitracing.com)

But !  Found that fuel pumps are rated at free flow, not at pressure psi.  Fuelish Tendencies (1bad69.com)

 

 

[harmony]

On 12/15/2021 at 7:48 AM, James_Douglas said:

If you go looking in my old thread you will find some stuff on these pumps. One thing is VERY important. They do not like to be run without fuel flowing through them. There is a specific amount of flow per hour that has to be maintained so the will not overheat.

 

The best thing to do is to put a "T" at the carburetor and a return line to the tank. Weld the "T" on the return side and drill a small hole, the size is in my old posts, which will allow for the proper flow so the pump never gets hot. Also, this help a lot with any hot day problems as in stop and go traffic the fuel is always cool at the carb input.

 

James

I don't mean to sound lazy James, But you have over 1600 posts.  I find this forum pretty difficult to navigate through, and maybe there is a way to narrow down my search of your posts, but I don't know how to do that.  

Sorry but I'm not getting a clear picture from your second paragraph.  So in the fuel line feeding the carb, and just before the carb, you put a T right?  So far so good. Here is where I get confused,,,, "Weld the T on the return side and drill a small hole"  Are we talking about a second T here ?  Weld it to what, and why weld it?  Drill a small hole where?

Edited December 18, 2021 by harmony

[TodFitch]

15 minutes ago, harmony said:

I don't mean to sound lazy James, But you have over 1600 posts.  I find this forum pretty difficult to navigate through, and maybe there is a way to narrow down my search of your posts, but I don't know how to do that.  

Sorry but I'm not getting a clear picture from your second paragraph.  So in the fuel line feeding the carb, and just before the carb, you put a T right?  So far so good. Here is where I get confused,,,, "Weld the T on the return side and drill a small hole"  Are we talking about a second T here ?  Weld it to what, and why weld it?  Drill a small hole where?

As I read/interpreted it, on the part of the T that the return line will be connected, weld or braze it closed. Then drill a small hole through the weld material. Result should be a restriction on the return path to limit the flow to the desired amount.

[harmony]

5 minutes ago, TodFitch said:

As I read/interpreted it, on the part of the T that the return line will be connected, weld or braze it closed. Then drill a small hole through the weld material. Result should be a restriction on the return path to limit the flow to the desired amount.

ooooooook, so would screwing in a reducer fitting do the same thing?  

Either way,,,so now you have a reduced dia. fuel line, going where, back to the fuel tank?  I don't think my 48 Chrysler has a return line.

[maok]

You can also buy a fuel filter that does the same thing. One inlet and two out lets where the return line is a smaller orifice outlet.

I believe Chrysler used it in later models, not sure when though.

[Bryan]

You can also get an electric fuel pump that is closer to your engine's requirements.   If it's on only when the motor is running, probably would work fine.  That's what I was trying to say in the post. The Airtex 8902 has 1/2 the GPH as the Carter 4259, and a lower psi rating more compatible with the Stromberg (3 psi).  The thing to realize is flow ratings are usually shown at free flow.  Look at some of the links.  Our engines aren't making 200-400 HP.

[Sniper]

5 hours ago, maok said:

You can also buy a fuel filter that does the same thing. One inlet and two out lets where the return line is a smaller orifice outlet.

I believe Chrysler used it in later models, not sure when though.

 

Fram G3583 or Wix 33040

 

You will have to run a return line back to the tank.

 

It will also help with any vapor lock issues you might have.

Edited December 18, 2021 by Sniper

[Sam Buchanan]

Me thinks getting rid of the mechanical pump right below the exhaust manifold will take care of vapor lock problems........

[Bryan]

3 hours ago, Sam Buchanan said:

Me thinks getting rid of the mechanical pump right below the exhaust manifold will take care of vapor lock problems........

Plus something like this might help for fuel lines in the same area. Weird, a few weeks ago found it in McMaster-Carr under "cable carriers".   https://www.mcmaster.com/cable-carriers/heat-reflective-corrugated-sleeving/  They have another type that is wrap around sleeving.

[Sam Buchanan]

37 minutes ago, Bryan said:

Plus something like this might help for fuel lines in the same area. Weird, a few weeks ago found it in McMaster-Carr under "cable carriers".   https://www.mcmaster.com/cable-carriers/heat-reflective-corrugated-sleeving/  They have another type that is wrap around sleeving.

 

Since I no longer have a mechanical pump, there was no need for the original fuel line routing around the front of the engine and near the exhaust manifold. When I replaced the fuel system the fuel line was rerouted on the firewall which is a much cooler and direct path to the carb.

 

Some might criticize this mod saying a fuel leak would be more likely to spray gas on the engine. I don't worry about this since the line and fittings are all new and easily inspected. I think getting the line away from the exhaust is a big plus.

 

Edited December 18, 2021 by Sam Buchanan

[Bryan]

Also getting it out of the front impact zone with rocks..and whatever was sitting on top of it.

[James_Douglas]

16 hours ago, TodFitch said:

As I read/interpreted it, on the part of the T that the return line will be connected, weld or braze it closed. Then drill a small hole through the weld material. Result should be a restriction on the return path to limit the flow to the desired amount.

Let me go find my notes on this...

 

One of my complaints about the board is the inability to do a serious SQL search on the database. It would be nice, for a price, if one could buy a read only copy of the P15-D24 database and do a SQL search with it to look things up. I paid a guy some years back for a copy of a MOPAR parts database and it has been great to run SQL to look up part numbers...

 

James

[James_Douglas]

Many years back when I talked with a tech at Carter this is what he told me according to my notes:

 

1. Part Number P4259 works on 6 volt positive or negative ground.
2. The rebuild kit (no motor) is part number 888-178.
3. The pump has a maximum pressure of 5.75 PSI.
4. This unit is a full time on unit and will not allow for a proper flow through if off.
5. This unit must be installed at a level equal to the bottom of the fuel tank.
6. This unit must be within 2 fuel line feet of the tank.
7. This unit typically drops between 1 to 1.5 PSI at the carburetor inlet.  Less loss for shorter fuel line runs (Coupes) and more loss for longer runs (sedans).
8. The only issue when using these pumps on small HP engines is as follows.  These pumps must have 5 gallons of flow every hour to keep within operating temperatures.  If you are at idle for over 30 plus minutes on a hot day in traffic and your engine does not pull enough fuel through the pump could overheat.  The thing to do according to Carter is to put a fuel line tee up in the engine with a 1/8 or 3/32 orifice and a return line to the gas tank.  That way the pump will always have enough fuel running through to stay with is temperature range.
   
   The carter man stated that he has heard of a few people with really old low HP cars in hot areas, on hot days, stuck in long parades, have pump problems.  It is rare, but if you want to make sure that it never happens, then put the return line in with the orifice.

**************
Now all the above said when I tested two out of the box 6 volt carter pumps I ran into an issue.

When I put a fuel pressure gauge on the "T" and checked it I got about 3-1/4 to 3-1/2 pounds.

Here are my many years old notes on that:

The original mechanical pumps are supposed to be between 3-1/2 and 5 pounds.  I thought that is a little on the light side, but once the generator is going, I guess the voltage will come up a bit and it will probably top 3-1/2 pounds.

I then did a flow test.  I put a graduated pale in the engine pay and ran the pump for one minute.  I got 3 Pints.

This is where things get odd.  The pumps according to Carter are supposed to put out between 6 to 8 PSI and up to 72 GPH.  That would be 9.6 Pints a minute. 

I called Carter and got a lot of double talk.

I hit my 1957 Carter Master book which is 5 inches thick.  In the back they have both the old Carter mechanical fuel pumps and the older larger vane electric fuel pumps.

In the section on the mechanical pumps they show how to test them.  They show their mechanical pumps, like the MOPAR manual, as having between 3-1/2 and 5 PSI.  They also show that the mechanical pumps are supposed to:

"Volume: One quart of fuel in one minute or less at 500 RPM"

In the section in the book on Testing, Removing, and Overhauling the older style electric Carter fuel pumps, it states:

"If the fuel pressure gauge is not less than the following the pump is satisfactory:

3 Pounds for a 24 Volt Pump.

2-1/2 Pounds for a 12 Volt Pump.

1-3/4 Pounds for a 6 Volt Pump."

If I use the old original Carter specifications, my newer style vane pump is just fine. When I talked with the people at the service center, they just mouth the 6 to 8 PSI and 72 GPH song.  When I asked for a PSI chart via voltage they tell me they do not have one.  I ask that surely the 6 volt, 12 volt, 24 volt versions have different outputs.  Nope, they are all the same I am told.  When I ask what the minimum volume output is they tell me they do not know.  I ask them to tell me how will they determine if a pump is defective if they do not know what to measure.  They don't know.

I took another unit and put 18" of rubber hose on it.  I took 3 feet of #12 wire and connected it.  I stuck the fuel gauge on the output of the pump. I put the end of the hose in the pale with the 3 pints of gas I took from the car test.  I turned it on.  Guess what, 3 PSI.

 

It is obvious to me that the published specifications are garbage. Carter to American Car and Foundry (ACF) to Federal-Mogul to now some outfit named Castle Automotive.  I think over the years that the original specifications have been lost and all that is quoted is the ones for the 24 volt version.

I call back later and talk to another person.  I explain what is going on. I asked for them to call up the food chain and confirm the minimum and maximum design parameters for pressure and flow for the six volt pumps. I am waiting on a response.

I very much doubt that 2 pumps via 2 distribution channels a year apart are both "failing" in exactly the same way output wise. 

***************

Basically what I am saying is take the published specifications of these 6 volt pumps with a big grain of salt. If it works it works.

I think over the yeas the real data is long lost.

James

 

PS. I have a friend who is a serious Cadillac guy. He has a 1958 Cadillac Eldorado Biarritz Convertible among other things. He told that in the late 1950's Cadillac used two fuel lines with a "T" at the carb if a car was ordered with Air Conditioning. This was to deal with vapor lock. I can see that is an electric fuel pump does not have enough flow through it during a parade or the like that the motor could over heat. I have run the return line on the '49 since day one and I never noticed any issues. I run it into the filler neck. We made a little pipe with a bed in it and welded it to the filler neck so the fuel returns there and runs back down into the tank. 

 

Edited December 18, 2021 by James_Douglas

[Sam Buchanan]

Whew.........paralysis by analysis...............................

 

Bottom line...under some very unusual circumstances that hardly anyone would encounter, and if the planets line up correctly (or incorrectly??)....there is the remote possibility of a pump failure......unless the new pumps don't match the decades-old data.......in which case all the data presented above is meaningless.

 

Just hook up the stinkin' pump by inserting it into your fuel line and enjoy not having to mess with the old mechanical pump.   ?

Edited December 18, 2021 by Sam Buchanan

[Sniper]

To be honest, it's guys like James that do the spade work and figure out what does work for us.   

[Sam Buchanan]

I have no problems with doing homework, done plenty of it myself. But sometimes we can just try something if it passes the common sense test, and it will usually work fine. 

 

I see this in the aviation community....get three engineers together and watch them postulate about the physics of holding a torque wrench. While they are arguing I replace my plugs and go flying.  ?

 

Just got back from giving a new couple a ride to their wedding reception. They and their guests loved the Plymouth.....and nothing burned up!

 

 

[harmony]

1 hour ago, Sniper said:

To be honest, it's guys like James that do the spade work and figure out what does work for us.   

Yeah, no kidding,,,wow!

[harmony]

1 hour ago, James_Douglas said:

Many years back when I talked with a tech at Carter this is what he told me according to my notes:

 

1. Part Number P4259 works on 6 volt positive or negative ground.
2. The rebuild kit (no motor) is part number 888-178.
3. The pump has a maximum pressure of 5.75 PSI.
4. This unit is a full time on unit and will not allow for a proper flow through if off.
5. This unit must be installed at a level equal to the bottom of the fuel tank.
6. This unit must be within 2 fuel line feet of the tank.
7. This unit typically drops between 1 to 1.5 PSI at the carburetor inlet.  Less loss for shorter fuel line runs (Coupes) and more loss for longer runs (sedans).
8. The only issue when using these pumps on small HP engines is as follows.  These pumps must have 5 gallons of flow every hour to keep within operating temperatures.  If you are at idle for over 30 plus minutes on a hot day in traffic and your engine does not pull enough fuel through the pump could overheat.  The thing to do according to Carter is to put a fuel line tee up in the engine with a 1/8 or 3/32 orifice and a return line to the gas tank.  That way the pump will always have enough fuel running through to stay with is temperature range.
   
   The carter man stated that he has heard of a few people with really old low HP cars in hot areas, on hot days, stuck in long parades, have pump problems.  It is rare, but if you want to make sure that it never happens, then put the return line in with the orifice.

**************
Now all the above said when I tested two out of the box 6 volt carter pumps I ran into an issue.

When I put a fuel pressure gauge on the "T" and checked it I got about 3-1/4 to 3-1/2 pounds.

Here are my many years old notes on that:

The original mechanical pumps are supposed to be between 3-1/2 and 5 pounds.  I thought that is a little on the light side, but once the generator is going, I guess the voltage will come up a bit and it will probably top 3-1/2 pounds.

I then did a flow test.  I put a graduated pale in the engine pay and ran the pump for one minute.  I got 3 Pints.

This is where things get odd.  The pumps according to Carter are supposed to put out between 6 to 8 PSI and up to 72 GPH.  That would be 9.6 Pints a minute. 

I called Carter and got a lot of double talk.

I hit my 1957 Carter Master book which is 5 inches thick.  In the back they have both the old Carter mechanical fuel pumps and the older larger vane electric fuel pumps.

In the section on the mechanical pumps they show how to test them.  They show their mechanical pumps, like the MOPAR manual, as having between 3-1/2 and 5 PSI.  They also show that the mechanical pumps are supposed to:

"Volume: One quart of fuel in one minute or less at 500 RPM"

In the section in the book on Testing, Removing, and Overhauling the older style electric Carter fuel pumps, it states:

"If the fuel pressure gauge is not less than the following the pump is satisfactory:

3 Pounds for a 24 Volt Pump.

2-1/2 Pounds for a 12 Volt Pump.

1-3/4 Pounds for a 6 Volt Pump."

If I use the old original Carter specifications, my newer style vane pump is just fine. When I talked with the people at the service center, they just mouth the 6 to 8 PSI and 72 GPH song.  When I asked for a PSI chart via voltage they tell me they do not have one.  I ask that surely the 6 volt, 12 volt, 24 volt versions have different outputs.  Nope, they are all the same I am told.  When I ask what the minimum volume output is they tell me they do not know.  I ask them to tell me how will they determine if a pump is defective if they do not know what to measure.  They don't know.

I took another unit and put 18" of rubber hose on it.  I took 3 feet of #12 wire and connected it.  I stuck the fuel gauge on the output of the pump. I put the end of the hose in the pale with the 3 pints of gas I took from the car test.  I turned it on.  Guess what, 3 PSI.

 

It is obvious to me that the published specifications are garbage. Carter to American Car and Foundry (ACF) to Federal-Mogul to now some outfit named Castle Automotive.  I think over the years that the original specifications have been lost and all that is quoted is the ones for the 24 volt version.

I call back later and talk to another person.  I explain what is going on. I asked for them to call up the food chain and confirm the minimum and maximum design parameters for pressure and flow for the six volt pumps. I am waiting on a response.

I very much doubt that 2 pumps via 2 distribution channels a year apart are both "failing" in exactly the same way output wise. 

***************

Basically what I am saying is take the published specifications of these 6 volt pumps with a big grain of salt. If it works it works.

I think over the yeas the real data is long lost.

James

 

PS. I have a friend who is a serious Cadillac guy. He has a 1958 Cadillac Eldorado Biarritz Convertible among other things. He told that in the late 1950's Cadillac used two fuel lines with a "T" at the carb if a car was ordered with Air Conditioning. This was to deal with vapor lock. I can see that is an electric fuel pump does not have enough flow through it during a parade or the like that the motor could over heat. I have run the return line on the '49 since day one and I never noticed any issues. I run it into the filler neck. We made a little pipe with a bed in it and welded it to the filler neck so the fuel returns there and runs back down into the tank. 

 

Good idea about running the return to the filler neck pipe.  I have a spare one from my parts car.  Do you have any pictures of when you did that?  I'm thinking you'd have to weld that while the filler neck was still in place.  But disconnected from the tank and the opening to the tank covered and with half a dozen people standing by with fire extinguishers in hand.   

What did you mean by,," we made a little pipe with a bed in it" Or did you mean to type "bend".  Are there any issues with the return line going uphill to the filler neck pipe?

Could you also drill and tap a hole in the fuel sender lid that's screwed on the top of the fuel tank, then thread in a 90 degree fitting for the return line.  Granted it would stick up a little bit so maybe a half moon plate could be made to go over it and under the trunk carpet, to keep things from catching on it.