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MG MGB Technical - fuel pump types

i have a 1968 bgt. can anyone tell me what fuel pump was fitted as standard?


also what is a solid state fuel pump? are these aftermarket additions?
MArk

Mark,
I had an electronic pump fitted on Saturday. Cost was £35 + vat + an hours labour. This is less than the SU or QH original types and should be more reliable.
Clark.
C. Corstorphine

Mark
There were two types of fuel pumps fitted to the MGB (SU HP) and (SU AUF300). Both pumps were manufactured by SU. I think that the latter rubber bumper cars used the AUF type. Given the age of your car you could expect that the fuel pump has been changed sometime in it’s life so you may not have the original type presently installed.
A solid-state fuel pump is one that uses a wiring circuit rather than sparking points to make the pump push fuel to the engine. All pumps are electronic in operation. Solid-state pumps are a more recent innovation so they are an aftermarket addition.
Cecil Kimber

Mark,
A solid state pump could also be one of the noisy little cubes that some suffer with. They are reliable, though.
David
David

Mark - As Cecil, says, the HP pumps and the AUF 300 pumps were used ont he MGBs. The HP is similiar in design to the L type pump, whereas the AUF 300 series incorporated some flow smoothing devices in it and came into use somewhere around 1965 or 66. Both pumps have about the same parameters. See my SU Fuel Pump 101 article at:
http://www.custompistols.com/cars/articles/dd_su_fuel_pumps_101.htm
for more information on the SU fuel pumps. Cheers - Dave
David DuBois

David(Florida) and Mark,

My new electronic(solid state) fuel pump is silent!
C. Corstorphine

You can get a solid state/electronic (no points) new SU fuel pump as I did or you can get a new original point style SU pump from Moss, etc. The electronic one still clicks which is a useful diagnostic tool to know if power is getting to the pump. My car stopped one day and when I noticed I didn't hear any clicks I looked under car to see that the hot wire had become disconnected. More expensive but worth it, I hope. The square Facet pumps are cheaper and dependable but noisy, I hear. You do have to be careful to get one that delivers the right pressure (2-3 lbs, I think, check the details) or use a pressure limiter to ramp the pressure down.
J.T. Bamford

I've got a Moprod electronic pump which I bought years ago from the Welsh MG Centre. It has a plastic body which means you have to be careful when installing it or you can strip the plastic screw threads, but it works fine and it ticks just like the original - so comforting to hear it in the morning. Some people have bad things to say about the Moprod, but apart from the plastic threads I see no problem.
Mike
Mike Howlett

A lot of you will start gnashing your teeth over this, and I know that I sound like a broken record, but, what the heck. A 1984/85 Honda fuel pump is just wonderful. They are cheap ($75.00-$85.00), reliable, produce the right pressure, look a lot like the SU, are easy to install and have the nice gentle clicking noise that stops when pressure builds. The fact that they are Japanese (made by Mitsubishi) will put a lot of you off, but they are hard to beat. Just my opinion.
David
David

David thanks for the tip. I will keep this mind incase a fuel pump goes on one of my cars.
I have an Austin Westminster too and the servo is starting to play up. I am looking for a cheap alturnative off a jap car to replce it (all be it on a temp basis)...my point being is there is nothing wrong with using modern parts...stand back and watch-out for flames ;-(
Cecil Kimber

To be exact---my fuel pump ticks on priming, as per original, but is silent in operation thereafter.
Clark.
C. Corstorphine

Is it silent? Or is it just that once the engine starts you can't hear it?
Mike Howlett

Quite possible Mike----it was only fitted on Saturday and I've only done 100 odd miles since. Maybe my old ears can't hear it over the din of the engine! That makes it silent to me I suppose!
Clark.
C. Corstorphine

More reliable? Maybe not. My V8 came with a 'pointless' pump and after a while started short-stroking and causing severe fuel starvation. Unlike the points type a quick thump does nothing and I had to wait until it decided to start working properly again before I could continue on my way. After the third occurence I replaced it with a refurbished points type and have had no more problems. Considering the original SU pump is one of the more longer lived items on the car, is so easy to get going again in most cases, and the unknown quantity of the electronic replacements, it seems a bit 'pointless' to replace them and I shan't be using one again. Have one for sale though ...
Paul Hunt

I am with Paul, the all electronic pumps are not necessarily more reliable than the points style pumps. The only thing that the all electronic pumps do for you is to eliminate points wear and burning. Properly adjusted points, with a working arc supression circuit will make the points last for many years before they start giving trouble. On the down side of an all electronic system is that when it does fail, you will sit beside the road until you get a new pump, which is why I am a strong advocate of carrying a spare pump. At this point, you are probably asking why the person who restores pumps and modifies they to solid state should make such a statement. I make the statement because in my work of restoring pumps, I have found that 50% - 75% of the pumps out there have arc suppresion circuits that are not working (it is very easy to damage them by leaving the pump energized when there is a clog on the inlet side of the pump, leaving the pump failed in a current on condition). Once the arc suppresion circuit is damaged, accelerated point wear begins and in a short time the pump fails completely.

Keep in mind that the pumps, whether all electronic or points type are an electro-mechanical device and is subject ro wear over the years. No matter how well they are enginered or built, they will eventually wear out and need to be replaced or restored.
Cheers - Dave
David DuBois

This thread was discussed between 07/10/2003 and 11/10/2003

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