Converting To Electric Fuel Pump

[KTMsm]

I have a 50s Hudson which has a leaking mechanical fuel pump

I can't find a rebuild kit so it's been suggested I change to a 6 volt electric pump

I've seen some for sale but surely I need a pressure regulator too ?

My "mechanic" says not
(old guy who helps me, who's right 50% of the time)

[Lotobear]

The Facet pumps are rated for a certain pressure range and provided your car is within what it needs then they are usually okay.

That said I've done a few leccy pump conversions on twin sidedraught Weber equiped cars and a regulator is very useful to dial them in correctly.

A Sytec regulator and gauge of Fuel/Filter King are not expensive though so IMO you have more to gain than lose by just fitting one

[Ambleton]

I have a low pressure fuel pump on one of my cars, which has an 80s motorcycle engine in it. The carbs in mine were only designed to run a gravity fed system so most pumps would easily overpower the float valve so I had to choose carefully.

A filter king pressure regulator (or similar) would give you more freedom on pump but I don't want another item under the bonnet on mine.

I used a Hardi Pump and am very pleased so far.

https://www.hardi-automotive.com/en/products/pumps...

They list fuel pressure in bar, and flow rate.

[AW111]

You probably only need about 5 psi.
Too much fuel pressure and it will push fuel past the float valves and flood.

[Ambleton]

AW111 said:

You probably only need about 5 psi.
Too much fuel pressure and it will push fuel past the float valves and flood.

Less than that.

Side draught Webbers are only good to about 3.5psi more than that and it pushes past the float valve and into the Venturi.

If the fuel pump is on a separate switch, then there's a possibility of flooding and hydraulic the engine if it is on for much more than a second before firing.

[catso]

My, carburettor Ducati Monster has a fuel tank from a later, fuel injected model and so has the in-tank pump, the pressure of which would most likely overwhelm the float bowls.

So, as the tank has a return line for the fuel injection setup, I simply piped up a 'loop' where the pump, pumps fuel back to the tank with a 'T' off the loop for the feed to the carbs.

I did consider fitting a pressure regulator instead but decided that might be more troublesome.

Works perfectly but does require a return feed to the tank, does your tank have a fitting or a breather that could be used as a return?

Edited by catso on Sunday 8th October 11:01

[OutInTheShed]

An SU type fuel pump like from a Morris Minor might be more in keeping?
Maybe even find a 6V one?
6V SU fuel pump on ebay, over £100 alas.

[Miserablegit]

I had issues when I fitted a filter king- they are quite big units and, as a result of under bonnet temps, I was having a lot of trouble with vapour lock as a result of all that petrol sitting in the filter king and getting very hot.
Fixed problem by finding correct pressure pump and removing filter king.

[EW109]

OutInTheShed said:

An SU type fuel pump like from a Morris Minor might be more in keeping?
Maybe even find a 6V one?
6V SU fuel pump on ebay, over £100 alas.

Still available new, but not cheap:

https://www.autoelectricsupplies.co.uk/p/su-fuel-p...