Electric Fuel Pump - pro's, con's, price, time?

M

Martin3500V8

New Member
I have a Late 1971 3500 auto, I was considering fitting an electric fuel pump to her to combat the infamous vapour lock these engines are prone to i was just wondering if anyone had any info or advice on how much it would cost and fit it, how much time it would take, what work would need to be done and what are the benefits or drawbacks to fitting this

Thanks
 
Hi Martin,
Does yours suffer from Vapour Lock?, if it's not prone to it then I'd stick with the original mech. pump.

My old '72 'S' had a Facet electric fuel pump fitted when I bought it. It was mounted in the engine bay and seemed simple enough to plump in. Just a power source, fuel pipes routed to and from it and the old mech. pump removed with the hole blanked off.
That car never had fuel vapourisation!
 
Hi young Martin :D

My first V8 suffered with "The Vapours". It would normally wait for the most embarrasing moment as well! :laugh:

My current V8 has an electric pump mounted underneath the car, and it's never had Vapour lock, even when stuck in heavy traffic in summer.
 
Keep your eye on e bay, I've got a silver top facet pump which I'll be putting up for sale next week when I get back from holiday.

This is more than sufficient to cure any vapour lock problems you may come across.

It's easily fitted, with a live feed, the mounting to the car is your earth, fuel from tank in one end, fuel pumped out other.
Best mounted near the tank rather than engine bay for best results
Dave.
 
If your fitting an electric pump, its worth sourcing an inertia switch, which cuts power to the pump in case of an accident. Just a safety feature, you can get one from the scrappy I think just about every injection car has one now, but I've had them off rover 200's and 800's.

Easy to fit, and might just save your life.
 
to avoid vapour lock, it helps to have a circulating system. i.e. fuel line from last carb goes back to the fuel tank.

I can't really see how fitting an electric pump would fix it as you are pumping fuel against a gas (vaporised fuel) that cannot go anywhere and it shouldn't make a difference if the pump is electrical or not???
 
That is a good point, although many people claim to have fitted the pumps and solved the problem.

As you say a circulating system would help, and probably remove the need for the electric pump. Not sure how that would be arranged with the SU's though. Maybe a pressure by-pass valve in the fuel line, like in an EFI system but at a much lower pressure, so it only operates when the needle valves close, use the reserve line as a return (or main line using the reserve line as main).
 
webmaster said:
That is a good point, although many people claim to have fitted the pumps and solved the problem.

As you say a circulating system would help, and probably remove the need for the electric pump. Not sure how that would be arranged with the SU's though. Maybe a pressure by-pass valve in the fuel line, like in an EFI system but at a much lower pressure, so it only operates when the needle valves close, use the reserve line as a return (or main line using the reserve line as main).
Click to expand...
Don't spend too much time thinking how to rig up a circulating system, Rover beat you to it! All V8's have one already.

I know people fit electric pumps, but I've never come across a V8 with the "vapours" that I couldn't cure using the standard system. Whether that would change since the advent of unleaded, I can't say yet!
 
Ahhh, having only ever owned 4 cyl models I wasn't aware of that, in which case maybe the electric pump just pushes more fuel around the system, the mechanical pump won't shift huge amounts at idle especially if the pumps a little tired.
 
Because of the return pipe it also means wherever you mount an electric pump (front or rear) it will always be pumping fuel from the rear even if the pump is front mounted.
And of course an electric pump will still pump fuel even if the engine is not running.(provided it's not wired thru an oil pressure switch)
 
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