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MG Midget and Sprite Technical - What fuel pump?

Hello all, as the 16 year project to get the 67 midget up and running nears the end I seem to be in constant need of advice so I hope someone can help with this one.

Mike has done an excellent job plumbing in my old fuel pump in exactly the place it came from all those years ago but it just doesn't have enough puff. No problem I thought, I can still read the part number - AUA 66. So after a little interweb searching I found www.sucarb.co.uk and ordered a brand new AUA 66. Only it's very different to my AUA 66 and I learn it is also a low pressure pump rated at just 1.5 psi with a maximum flow of 8 gallons an hour. Nothing like enough to keep the car going I believe given that I intend to use it for sprinting.

So, it must go back but what should I get instead?

I'd like to mount the pump to use Mike's braided plumbing which means on the bulkhead adjacent to the washer bottle. But will re-plumb if absolutely necessary.

Do I need to use a "red top" or a "silver top" - not that I know what either is? Do I need to use a regulator? If so which one? What is the difference between a "long pull - short push" and a "short pull - long push"? Can anyone point me in the right direction please?

Three pictures that might explain my problems can be seen at http://tinyurl.com/fuelpumpproblems - I don't think I can attach more than one to this post. The first "Fuel pump location" is a picture under someone else's bonnet showing where my pump is located and the other two are shots of my original pump and the nice new one. I know that the new one has a different number under the base but Burlen Fuel Systems Limited who supplied the pump tell me that this is the correct number for the correct base for the AUA 66. They also tell me that my AUA 66 (the British Leyland part number is still very visible) is a hybrid of unknown origins.

All ideas and suggestions will be welcome.
BillMex

How do you know the pump is inadequate?

Fuel pumps in the engine bay of the Spridget always seems to be problematic and you rarely if ever see a car with a pump in that position.


Daniel Thirteen-Twelve

Thanks for responding so promptly Daniel. With the old pump re-plumbed to its original but admittedly odd position under the bonnet, we have been having some fuel starvation problems and the in-line filter between the pump and the carbs is barely showing any fuel (unlike the one on my 72 Midget which is generally almost full of fuel).

So we borrowed a fuel pressure gauge and found that the old SU would stop clicking (pumping) before the gauge (which we've tested and found to be working fine) would read any pressure.

Assuming that we were to re-plumb with a replacement pump in the boot or in the original position just forward of the rear axle (where they collect all sorts of mud and stuff) do you have a recommendation for a pump and regulator?

Thanks again.
BillMex

BillMex

since all you can expect are opinions and this is based on your 67 car, in my opinion the pump is in the wrong place anyway and if mounted there is likely to be a low pressure high suction Morris Minor "sucker" pump

The proper place for your pump ought to be within the arch section behind the rear crossmember above and in front of the rear axle and this would be a higher pressure "Pusher" pump.

I've seen some opinions in here that these names are meaningless but after years of fitting new pumps at the roadside in an earlier life I can vouch for the fact that the two types of pump exist (or at least, did!)

Minis and Spridgets always had pushers and Moggies always had pullers/suckers. In fact I could have been disciplined and even dismissed by my employers if I fitted the wrong one to a car

It is not a surprise to see a wrong type fitted if a failure occured and the proper type was unavailable at some time though

You should find a bracket or at least the protruding studs for them on the inner rear bulkhead just above and to the right of the propshaft tunnel

I hope you can soon get your car on the road
Bill sdgpm

Thanks Bill. In your experience would an original pump refitted in the correct place be adequate for Sprinting or would you recommend an uprated pump (with or without a regulator)?

Thanks again for your response.
BillMex

The pump in my picture is a replacement from Quinton Hazell, works well, delivers all the pressure I need too even on high speed trackdays

but even this doesnt fill my filter canister near the SU HIF44

The only drawback I have is that it is a constant recirculator that "always" can be heard 'clonking' behind me


Bill sdgpm

The fuel filter that doesnt fill up

ever

and even when filled up srtificially empties almost completely when put back in service

I used to worry

now I just enjoy the car


Bill sdgpm

This thread was discussed on 08/03/2009

MG Midget and Sprite Technical index

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