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MG Midget and Sprite Technical - Electric pump?

A very nice and experienced AA man repaired (yes repaired!) the mechanical pump on my 1500 yesterday on the way to a peak district cottage. It is the big 40 with the attractive assistant tomorrow so he saved my bacon.
The pump is just 4 years old and needs replacing to be on the safe side. Can anyone remember the model / spec of an electric pump that would be an alternative? Just wondering if that would be a better bet and an easier swap if broken in the future.
Dave Squire

The original pump, which should be an AC Delco type Y if my old brain is working right, is easy to swap if you're going to carry a spare to cover breakdown and super easy to rebuild at your leisure. The rebuild kit is readily available as the pump is still in widespread use, for example on a number of small industrial engines.

As to electric pumps IDK but it seems to me, possibly wrongly, that A series cars appear to have more fuel pump problems than the Triumph engines. It's a long time since I had any trouble with a mechanical pump. Personally I'd stick with it but other, wiser heads may feel differently.

Well done to the AA bloke though. I doubt there are too many who would go to the trouble rather than just tow you.
Greybeard

It seems very odd that a mechanical pump only 4 years old should fail anyway! What was actually wrong with it?
Diaphragms do eventually give up, but should last a lot longer than that. There is a problem in that some of the later "copy" aftermarket pumps are rivetted together instead of using screws, which makes replacement of the diaphragm rather harder to do!
GuyW

Thanks chaps, the pump has screws so he looked. Diaphragm ok but outlet retainer and spring dropped out onto the diaphragm in the pump. The retainer is a flanged brass ring pushed into the top body of the pump from the inside. Looks like it could be a non return valve assembly on the outlet orifice. He put the spring back in, scuffed the retainer ring and pushed it back in. Unfortunately he didn't have any locktight with him so gentle driving at the moment.
Good point about electrics Greybeard. Now you mention it I used to carry spares for my moggy 1000 electric pump when I was a lad.
The car is doing 5 to 6000 miles a year so its odd to me that this should happen now tbh.
As you say maybe best get spare mechanical pump.
Dave Squire

Sounds like a manufacturing defect then. As Rod says, these pumps have been used on so many appliucations it seems odd that it should fail.

My guess is that any AA many worth his salt would relish the opportunity to carry out a repair of this sort. Far more interesting than the usual tow to a garage or jump leads for a flat battery.
GuyW

No troubles if you have a fit'n'forget type of electronic pump like the one in photo.

Points types (SU included, like they have on Minors and midgets), Moprod, possible some Facet installations if they're not suitable - now they're all a different matter.

Because I want a fuss free reliable pump I fitted the likes of below (a QH) as soon as I got my Midget over 10 years ago and have never touched the fuel pump since fitting it or worried about it, or had to prime it or carry spares.

http://classicparts4cars.co.uk/mg-midget-electronic-fuel-pump---auf214--qfp171e-133-p.asp

(13312) - https://www.hardi-automotive.com/en/products/fuel-pumps/


Nigel Atkins

Nigel, I agree, I have one of those as a replacement for an original "points" one. Its a good upgrade for the electric pumps used on the A series engines.

But the type that Dave has should be no less reliable than yours. If you think about it, they are much the same as regards the pump valves and diaphragm. They differ only in that yours is actuated by electronic circuitry and an electromagnet, whilst Dave's is actuated by a simple lever off a cam lobe on the camshaft. This may well be more intrinsically reliable in design terms than yours!
GuyW

ETA: I've given recovery service patrol personnel enough "interesting" problems with my current Midget let alone previous daily classics for them and I to have our full fill of them.
Nigel Atkins

Sorry Guy missed your post - the problem is with modern made parts, original mechanical pumps I'd guess were just as, if not more, reliable as the QH type electronic pump but I'd say by lots of experience of modern parts that modern made mechanical pumps are probably a lot less reliable, as it appears with Dave's - I wish it wasn't so as it makes classic ownership a pain often.
Nigel Atkins

Where I do think the mechanical pumps are less good is that in order to prime the carbs the pump has to be operated by turning the whole lump of the engine over. In difficult starting conditions, if the fuel in the carbs has evaporated - or worse, if the car has been left with the choke out allowing raw fuel to drain through from the carb and into the engine to wash oil off the bores and to dilute the oil in the sump, then the drain on the battery in operating the mechanical pump is far greater than for operating the electric one.
GuyW

I had a senior moment and had to check the 1500 pump hand a handle but having done so - if the carbs are empty doesn't the 1500 owner have the ancient joy of, er, pumping the mechanical fuel pump(?). Bringing nostalgia for the crank starting handle to save the battery even more. :)
Nigel Atkins

Some had the bonus if the little pump lever,but it wasn't on all of them. My '78 1500 didn't have the lever but my son's briefly owned Spitfire 1500 did!
GuyW

I'm almost certain, allowing for my poor memory that my GT6 had a pump with a handle (but it might have had an electric pump knowing my memory) and when looking up the 1500 just now it said on the MGB Hive ebay listing "there were two different pumps fitted to the 1500 Midget and the angle of the plunger must be compared before fitting".
Nigel Atkins

The two pumps had different length and shape of lever arms (plunger ?? ), so one is bolted up to the block with a spacer, whilst the other omits this. I cannot remember if this different length of lever arm coincided with the presence or absence of the manual pump facility.
GuyW

hi all
I dont use my 1500 daily so suffered as many above with having to pump fuel to the carbs on the starter..i had no lever on the pump
I bought a solid state pump from 'simombbc ignition'
with a line filter and all has been well since. Moss do a blanking plate to cover the opening in the block for the pump. All that 5 years ago. Best bit is the priming the carbs and then starts first time.
Not for the traditionalist but fine for me !

rgds tony
tony boyle

AA fella definitely enjoyed himself Guy. Actually happy to fix it. He was saying most moderns parts unfixable. And he worked on MG and plastic pigs as a lad. He had an almost beatific smile while working on it. Unlike one young AA chap who said 'so this is an MG midget is it'. I talked him through fixing it a couple of years ago.
Anyways, my car always has fuel in the dashpots unless there is a fault, even if left to stand for a week or more.
I'll order another pump for delivery asap and refurb the present pump as a spare.

Thanks all.
Dave Squire

Thanks Guy, now I realise my misinterpretation of plunger, not lever. I can only remember ever seeing pumps with levers, but then again I probably wouldn't have noticed the lack of a lever.

It's amazing the number of small differences there are in each model and years let alone market, of Sprites, Spridgets and Midgets.
Nigel Atkins

hi
one more point..if you go down the electric pump route, make sure you dont get one with too high output
From memory, should you have a 45 or 40 dcoe
you will need a very low pressure pump..4 to 4.5
psi
rgds tony
tony boyle

I'm with you Tony, get the car started, running and driven above originality.

It's nice to see originality but that does limit the car's use, to almost nil or practically nil in some cases.

ETA: the Hardi pumps are 2.5-3 psi up to 17 gal/minute
Nigel Atkins

Slight thread drift warning!

My 1275 has been starting and running, but with an erratic misfire over the last week or so. But not fuel pump related as the misfire was accompanied by the tell-tale flicking of the rev counter. I put it down to residual damp having had the engine cut out completely when going through some floods last week.

Anyway when I opened the bonnet, intending to take off the dizzy cap to dry it out, I found that one of the coil spade connectors was completely disconnected, and simply lying loosely on top of the coil terminal. Amazing that it still managed to run at all like that! I can only think that I caught it when I used a towel to wipe off the dripping flood water. In which case I have done the better part of 100 miles with it like that since then. Quite impressive what these "primitive" cars will put up with!

GuyW

AFAIK the various pumps used for 1500s are interchangeable, give or take the spacer. I heard a couple of theories why the spacer was used on some. One was that it isolated the pump from the heat of the block and another that the longer lever of the spaced out pump reduced the displacement as the short lever pump flowed too much fuel, since it was capable of supplying bigger engines like GT6s. Bottom line is IDK - both seem plausible to me.

But I do remember a conversation with a chap I worked offshore with about his B having to crank for ages after it had stood a few weeks. I have the vague idea it had a single carb, maybe a Stromberg, as it was a US car. His solution was to plumb in a priming bulb from an outboard motor in the supply hose which he reckoned did the trick.

Okay - not particularly relevant to Dave's question but I can see no reason it wouldn't work on a 1500 to save grinding away on the starter to fill the carbs.
Greybeard

When I had my 1500, there was a starting routine that I found reduced the time spent grinding away on the starter. This was to turn the engine over through just 3 or 4 revolutions maximum. Then wait for a count of 10 (long enough to put the seat belt on). Then a single rotation on the key and it would fire up.

I think what happens is that the pump builds up sufficient fuel pressure in those first 3 turns and the following delay allows the fuel to continue to flow through to fill the carbs.
GuyW

Nigel,

I've seen petrol pumps with plungers rather then levers but can't think of the application at the moment.

Regarding electric pumps being unreliable I think they get bad press for that as by the time they do get unreliable they've been around a long time and likely long past their design life. I've never had one go bad myself but had to give a friends Mini pump a whack on occasions.
David Billington

"But I do remember a conversation with a chap I worked offshore with about his B having to crank for ages after it had stood a few weeks. I have the vague idea it had a single carb, maybe a Stromberg, as it was a US car."

AFAIK all MGBs had electric pumps.
Dave O'Neill 2

Yep I'm sure you're right Dave. I thought so too. But for some reason this fellas pump wasn't up to the task of priming whatever carb it had straightaway after it had been standing awhile so he added the squeezy bulb.
I would imagine that an electric pump at the tank should do the job fine if it works properly so I was a bit dubious about it at the time, but he said it fixed the problem. It was only now that I thought it might be a cheap and easy way to fix the issue on a 1500 with its low tank, high carbs and engine driven pump which has a long way to pull the fuel.
I've had the same problem occasionally with my 1500 after I've left it but I've always got away with it as my driveway is fairly long and downhill all the way so it's reasonably easy to bump start without troubling the electrics. (Except the one time I completely forgot about the battery isolator switch).
Greybeard

Congrats on your 40th, Dave. Hope you're doing something wonderful.
Nick and Cherry Scoop

David,
thanks, sorry to say I was confusing the name of the lever to manually pump the fuel pump rather than the technical differences between plunger and lever pumps which I didn't know existed until you mentioned it.

You now owe me two paracetamols! :)
Nigel Atkins

Dave,
I read it as your attractive assistant was to be, now is, 40, either way Happy Birthday to you or your attractive assistant.

Thanks and well done to Nick for pointing this out.
Nigel Atkins

Nigel,

A number of the Ford engines used plunger pumps such as the Pinto and apparently the V4 and V6. http://www.burtonpower.com/mechanical-fuel-pump-ford-sohc-pinto-85-early-cvh-ffp449.html
David Billington

Certainly hoping there's no answer from Dave today.
Nick and Cherry Scoop

David,
that explains it, 1985, too modern for the Pinto engine I had. :)
Nigel Atkins

This thread was discussed between 02/12/2017 and 03/12/2017

MG Midget and Sprite Technical index

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