1955 electric fuel pump versus original manual fuel pump or both

[dnhodge1]

When I got my 55 it already had a electric fuel pump with all lines running through the manual fuel pump with a pressure regulator added before the fuel filter. The seals on the manual were shot so I had it rebuilt. So do you guys think the electric pump might have had something to do with the seals going out or maybe it was jus that time. And now that I have the rebuilt manual, should I go with both again or block off the manual and just use the electric. I know I won't have windshield wipers but I could buy a motor for those too. And if I block off, what do I do about the line that goes to the engine block ? Advice and opinions appreciated. Thanks

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[Yadkin]

When I got my 55 it already had a electric fuel pump with all lines running through the manual fuel pump with a pressure regulator added before the fuel filter. The seals on the manual were shot so I had it rebuilt. So do you guys think the electric pump might have had something to do with the seals going out or maybe it was jus that time. And now that I have the rebuilt manual, should I go with both again or block off the manual and just use the electric. I know I won't have windshield wipers but I could buy a motor for those too. And if I block off, what do I do about the line that goes to the engine block ? Advice and opinions appreciated. Thanks

The advantage of an electric is that you can wire it to a key on circuit, and thus prime the carburetor before engaging the starter. A car not driven in a while will evaporate all the gas in the float bowl, meaning that you will have to crank for a lengthy time before it refills. You should always wire the pumpo using a relay triggered by an accessory circuit and have an inertia switch in the new circuit to shut off the fuel supply in event of an accident.

 

[Ward 57]

The advantage of an electric is that you can wire it to a key on circuit, and thus prime the carburetor before engaging the starter. A car not driven in a while will evaporate all the gas in the float bowl, meaning that you will have to crank for a lengthy time before it refills. You should always wire the pumpo using a relay triggered by an accessory circuit and have an inertia switch in the new circuit to shut off the fuel supply in event of an accident.

There is nothing wrong with letting a sitting engine crank a bit at least enough to turn off the oil light before firing off. Pre loading it with oil pressure will do wonders in prolonging it's life.

 

[Yadkin]

I disagree. Most engine wear occurs during startup, since the oil pressure at cranking RPM is very low.

 

[Ward 57]

I disagree. Most engine wear occurs during startup, since the oil pressure at cranking RPM is very low.

That's what I was saying. Crank it until the oil light goes off. I have talked to race car engine builders and they have two switches, one to crank the engine and one to turn on the spark.

 

[willcarterdc]

I have no insights on whether the electric pump may have caused the failure of the seals on the mechanical pump: I’m sure others with greater knowledge will weigh in on that. I’m wondering, though: now that you’ve had the mechanical pump rebuilt, why not just go with both? That is, set it up so that it runs primarily on the (now-rebuilt and presumably working properly) mechanical pump and put the electrical pump on a switch so that you can flick it on only when needed then flick it back off. That’s how mine is set up.

When I originally got my ‘57, it (1) would need to crank for a really long time before it would start if I tried to start it using only the manual pump (and yes, I was following the recommended starting procedure), such that I got in the habit of always using the electrical pump to prime before trying to start and (2) would only run properly if I kept the electrical pump on at all times while driving. Now that I’ve had the manual pump rebuilt, it runs perfectly on the manual pump alone and starts pretty much instantly without needing to prime using the electrical. (Like, it fires right up after cranking for maybe 2-3 seconds, regardless of how long the car has been sitting. It now starts so quickly that I almost wonder whether something is “wrong.”).

 

[zeroroadkill]

if the mechanical pump, diaphragm failed when in series with an electric fuel pump there’s a possibility fuel can be forced into the crank case. This is the reason I bypassed the mechanical pump and went directly with the electrical pump to the fuel filter line, but I left the connections on the mechanical fuel pump so in case the electric pump dies I can do a quick hose swap. If you bypass the mechanical pump and leave it installed, you will not lose vacuum to your windshield wipers unless the pump is shot. I’ve had several replacement pumps failed to pump fuel, but always operate the vacuum to the windshield wipers. If you install electric fuel pump, make sure to install an inertia switch. The electric pump gets its power from the ignition switch and most come with a manual under dash switch to turn it on and off. This is good to prevent drive a ways!

Sometimes the reason for long cranking before starting is due to backflow through the fuel pump back to the tank when sitting or evaporation in the float bowl. This is where the electric pump comes in handy to prime the fuel bowl before cranking. I usually prime the carburetor for a few seconds, three pumps on the pedal & crank about three seconds and start.

 

[doug7740]

if the mechanical pump, diaphragm failed when in series with an electric fuel pump there’s a possibility fuel can be forced into the crank case. This is the reason I bypassed the mechanical pump and went directly with the electrical pump to the fuel filter line, but I left the connections on the mechanical fuel pump so in case the electric pump dies I can do a quick hose swap. If you bypass the mechanical pump and leave it installed, you will not lose vacuum to your windshield wipers unless the pump is shot. I’ve had several replacement pumps failed to pump fuel, but always operate the vacuum to the windshield wipers. If you install electric fuel pump, make sure to install an inertia switch. The electric pump gets its power from the ignition switch and most come with a manual under dash switch to turn it on and off. This is good to prevent drive a ways!

Sometimes the reason for long cranking before starting is due to backflow through the fuel pump back to the tank when sitting or evaporation in the float bowl. This is where the electric pump comes in handy to prime the fuel bowl before cranking. I usually prime the carburetor for a few seconds, three pumps on the pedal & crank about three seconds and start.

CASCO sells a fuel line chck valve that helps eliminate hard starting by not allowing gas to drain out of the fuel line back to the fuel tank during storage.



If you want to use your electric fuel pump as the main fuel pump and are worried about possibility that fuel can be forced into the crank case through your old mechanical fuel pump, CASCO sells a by-pass kit for your mechanical fuel pump. Used in conjunction with the electric fuel pump, this kit eliminates the possibility of the electric fuel pump forcing fuel into the oil pan if the original diaphragm and seal are compromised. This kit converts your original mechanical pump into a straight-through mode. This is useful if the fuel side of the mechanical pump is not working but the vacuum side still works, or if you want to maintain the look of the original pump while using a remote electric fuel pump.

doug7740
1955 Thunderbird Blue

 

[Oly Bob R]

Is your 55 still 6 volt and if so where did you find a 6 volt fuel pump and are they still available. My fuel pump will overheat and then go into a vacuum

 

[zeroroadkill]

I believe it was CASCO
thread.https://forums.fordthunderbirdforum.com/threads/1957-fuel-pump-not-pumping.15219/#post-91657

 

[Harleyhoot]

That's what I was saying. Crank it until the oil light goes off. I have talked to race car engine builders and they have two switches, one to crank the engine and one to turn on the spark.

Race engines are different, most have very high compression ratios,,,,,,,12:1 to 14:1 and extreme ignition timing....so it becomes nessesary to get the engine spinning before applying ignition.......that way the poor starter doesn't have to fight compression and ignition at the same time.

 

[zeroroadkill]

And race engines have a dry sump oil system with a electric oil pump which pre-oils the engine befor ignition.

 

[CSPIDY]

I’m running the mechanical with the CASCO electric pump mounted as recommended by experts.

I added a 2 1/2 psi pressure switch near the carb to control the operation of the pump (gnd)
plus a manual switch

Power side I have a Ron Francis crash sensor and relay
I’v also put an LED light on the power side that tells me when the pump is operating

It works quite well and so far it actually helped during a vapor lock incident

First start of the day,
I turn the key on and can hear the pump running then when it stops
two pumps of the pedal, hit the starter and it starts right up

 

[zeroroadkill]

I did install the inertia crash switch by the battery and a under dash switch to the power lead to the pump as kind of a anti-theft deterrent since I bypassed the mechanical pump. But if they hotwire her they’ll probably find the switch ?