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MG Midget and Sprite Technical - Facet fuel pump

I have just bought a Facet pump to replace the SU pump - provides fuel to the swirl-pot with overflow back to tank.

The question is: is it OK to stall these pumps (in a simular way to stalling SU pump when float chamber full)?

(At present it will pump continuously - sounds like a WW-1 machine gun; so can ut restrictor in fuel flow to cut down on pump cycles.)

Thx, Anthony
Anthony Cutler

which pump Ant?
cube or cylindrical?
model number?
David Smith

Hi David

You are trying to confuse me with your highly pertinent question...(!)

FEP06SV (it says on the receipt).

Anthony Cutler

hmmm if you can equate that # to one on this page
it says they are 'self-regulating' which I think means they stop pushing fuel but keep on ticking.
I guess we need to understand how they work - apparently they don't have any 'contacts, diaphragms or bearings so last up to 6 times longer than otherpumps'.
David Smith

Thx, David

Yes - had a quick look on the web befoe posting, and there's nothing conclusive.

"no bearings, contacts..." seems that fuel is pumped by the sheer will-power of 12v EMF.

Does anyone use this type of pump with SU/Weber float chamber?

Will install it anyway and see what happens to supply current when I stall it. If it goes to zero, then it should be OK; if it increases, then probably best avoided.

Anthony Cutler

Installed and running OK; seems to hammer at same rate whether stalled or pumping free... so must use a bypass valve.

I found that by restricting the flow slightly it reduces the hammering significantly, so have reached a compromise.

Would still be interesting to know what's inside the pump body...

Anthony Cutler

Time to destroy and dissect then. ;)

Ever since you posted this, I've been searching for a description of the internals. The only thing I can come up with, is pulse width modualtion, and peizoelectric effect. Maybe that's how they work?
Lawrence Slater

Gentlemen - The Facet pump does run continuously, even with the float bowl full and the needle valve shut off (I have derisively called them, the little, square, run all the time, make a lot of noise pumps). As for the noise, get a couple of the rubber, bobbin like mounts for the exhaust mounts on one of the midget models (I am not a Midget owner, s can't say which model) and mount the pump on those - you will barely be able to here the pump then, even with the engine shut off. Cheers - Dave
David DuBois

L, D

Thx for comments.

It's currently mounted on its short fuel hoses; still easy to detect when the engine's off.

Need to take one apart! Does anyone have one that's u/s?

Anthony Cutler

"It's currently mounted on its short fuel hoses; still easy to detect when the engine's off."

But if you have a screw or bolt running through the hose, it is providing a sound short directly to whatever is is mounted to. You need those bobbins that have a stud at either end of the cylinder of rubber in between - no through bolt to cause a sound short.

Why do you need to take one of the Facet pumps apart? They have a check valve for inlet and outlet and a piston, with a bypass valve in it moving back and forth in the pump. They are simple - work fine, lasts a long time (at least as long as a SU pump). There is noting in them that can be replaced or fixed - when they die, bin them and get a new one. Cheers - Dave
David DuBois

I don't have one that is u/s as I've found them to be incredibly reliable.

I have used them on all of my race cars over the years and even carried a spare pump, just in case. I never needed to call on its services!
Dave O'Neill2


If my thoughts are anything like Anthony's, and I think they might be, the reason for taking it apart is sheer curiosity. I need to know the insides and outsides of everything in life. I annoy the hell out of people. :)

Of course Anthony probably has a far better reason than that. :)
Lawrence Slater

... not really... I've been taking things apart since I was around 4 years old... putting them back together is the secondary part of the hobby... been doing that on an occasional basis. ;)

Anthony Cutler

Ah well that's just like me then. Nothings sacred or safe from my prying. lol.
Lawrence Slater

Anthony & Lawrence - it is a disease that a lot of have had since childhood (I did disassemble a Facet pump that was on a Mazda pickup that I had years ago - unfortunately the electronics was encased in a solid lump of sealer). Cheers - Dave
David DuBois

If your feeling flush Facet do a nice rubber bobbin fitting kit. I got mine from Merlin Motor sport. No sound apart from the regular click!! BTW Its a silver top which I run straight to the SU's without any restrictor. Its got to be 15 years old now and no probs at all.
Bob Beaumont

This thread was discussed between 06/04/2012 and 09/04/2012

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