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MG Midget and Sprite Technical - I need S.U. Fuel pump advice

Hey Guys,

I need some advice and insight om my SU fuel pump, Im not sure as to which one it is but the car is a USA spec 1275 1971

My fuel pump has been slowly going bad all summer long, when I go to start it I have to beat it with a handle of a screw driver and it runs fine, It is no longer making the tick tick tick noise its supposed to when you start it up, and Im having to beat on it more and more


So Im wondering should I buy a new one from moss or northwest, ect.,

should I get that little electronic square box one from napa auto parts,

sould I get the newer electronic SU pump made by Su that dosnt have the points and diaphram,

or should I get a rebuild kit and rebuild it

or is there another option

Work is really slow this year, and Im not making the money I used to. so Im leaning towards ither the little square box from napa auto for $50 or rebuilding it, I just dont know what is the best approach, do these pumps work as good when you re-build them, any special tools needed to rebuild them...as to the piston, (Im guessing it has one) do I need to hone the cly. or new rings or anything like that..


anyway thanks in advance for any insight, past experiance, thoughts, or advice that you guys might have

Prop
Prop

BTW....

Im thinking If I have to pull that stupid thing out of the rear wheel arch, Then I might as well install it in the (BOOT) trunk, is that a problem, will that effect the fuel flow, it just seems like a better place then in the wheel well...

I do know that the angle of the position of the fuel pump is sitting in, is vary curical for the best optium performance...So I didnt know if I installed it in the (boot) in that same angle of position if the Fuel pump would still work as it did in the wheel well.



thanks
prop
Prop

Prop - The OE pump for the midget is a AUF 214. They are the cheapest of the SU fuel pumps so it shouldn't break the bank to replace it with an original. The little, square, run all the time, make a lot of noise, Facet pumps will work fine, but will probably drive you crazy with the noise unless it is sound mounted. If you get another SU fuel pump, it should be mounted (regardless of where it is installed) with the outlet at the top for the most efficient operation. As to whether to get the points style or all electronic style, this depends on how much you drive your car. If it is driven regularly and not put in hibernation during the winter months, then a points style pump will serve you very well. If, on the other hand, your car is not driven on a regular basis and is laid up each winter, then the choice should be the all electronic pump. Finally, the pump can be rebuilt, either by yourself or by any of the people in the US who are listed in the article, Fuel Delivery Troubleshooting Guide in the SU Fuel Pump Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ Cheers - Dave
David DuBois

Buy a facet pump, i've used both types in the past with no problems ever, unlike the SU one. Just be sure to mount it on rubber exhaust mounts to reduce the noise/ vibration.
Also depending on your set up you may need a fuel pressure regulator, i use a glass bowl filter type, with adjustable pressure for my dellorto 45 DHLA.
cheers
Brad
B Richards

SU pumps are good for at least 12 -15 years before they need attention, but are their own worst enemy - they keep going long after this by virtue of the tap, hit bang! Instead of fixing them people just give it another wack and mutter how unreliable it is. Would you keep driving your car on duffy points in the distributor and the engine misfiring badly as a consequence? No? Of course not - that's why I can't see why people do with their fule pump!

Wisely Prop is going to do something about it. I'm for rebuilding the SU. With new points and diapragm (the principal items which get tired) properly set up, it will do another decade and more.

One thing which is worth adding is a capacitor of around .01-.05 uF. This supresses the spark and prolongs the life of the points (just as the capacitor in the distributor does.) Voltage rating will need to be 200V or more.
Paul Walbran

I didnt realize that the SU fuel pump is the Bain of peoples existance ...I have no bad feelings towards the SU pump personally....after all nothing last forever, and this is one of the few things I never replaced when rebuilding the car. So considering the car is 37 years old...I certianly cant cry about it going bad. If anything Id say that a good piece of engienerring


Im leaning towards the NAPA sq box, simply cause its cheap, easy to install, (newly made in china...so should last at least 50 years ..lol) and the napa store has one in stock,

Id perfer the SU cause of its dependability...cant argue with 37 years of good service, but Im not sure that just points and a diaphram, will be the cure all, After all, will there be other parts to the pump that wear out as well that are going to show up 2 weeks later.....personally Im enjoying the break from working on the car this year (hard to believe i know)

Is this a sign that maybe its time to retire the current 37 year old fuel pump.

Prop
Prop

I didnt realize that the SU fuel pump is the Bain of peoples existance ...I have no bad feelings towards the SU pump personally....after all nothing last forever, and this is one of the few things I never replaced when rebuilding the car. So considering the car is 37 years old...I certianly cant cry about it going bad. If anything Id say that a good piece of engienerring


Im leaning towards the NAPA sq box, simply cause its cheap, easy to install, (newly made in china...so should last at least 50 years ..lol) and the napa store has one in stock,

Id perfer the SU cause of its dependability...cant argue with 37 years of good service, but Im not sure that just points and a diaphram, will be the cure all, After all, will there be other parts to the pump that wear out as well that are going to show up 2 weeks later.....personally Im enjoying the break from working on the car this year (hard to believe i know)

Is this a sign that maybe its time to retire the current 37 year old fuel pump.

Prop
Prop

Prop, I did mount the new SU 214 in the boot. At the inside of the rear right wing. Its fixed against the reinforcement panel. Its protecion wise the best place but I do get some fumes in the boot. I tightened every hoseclip as fast as is possible but there are always some fumes. Not a good idea to open the trunk with a good Havanna in your mouth:-)

If you want I can make some pictures.

Bas Timmermans

I would never mount the fuel pump in the boot. Between fumes getting into the car & the damage any leak could cause not to mention all the electrical connections to the tail lights creating a spark, hoses chaffing on the sheet metal even if the holes are properly grommetted this is just a disaster waiting to happen. Since the pump is a very low maintenance item I would leave it outside the car where it was originally located. Also, some state / motor vehicle safety inspections would fail you for that installation for the reasons outlined above although your situation may be different.
Mike G

By the way, fuel pumps don't draw fuel particularly efficiently when they are above the fuel level. Keeping it low is definitely a better installation. You may be able to open the pump & clean the electrical contacts & get some more life out of the pump. They do get a bit of carbon on them but if they're not worn out or badly pitted you may be able to keep it alive until times are better financially.
Mike G

Prop

In general, the only other components which could fail are the valves and the coil. In practice the failure rate of these, particularly the coil, is so low that they can be re-used with confidence.

My "new points & diaphragm" recommendation was in the context of your thoughts about optimising value for money at present. Both coil and valve kit are quite expensive, and in the (very unlikely) event of either of the failing the pump doesn't take long to remove and fix.

As you say, the original pump has done 37 years, it could do that again if given the chance.
Paul Walbran

I use the little square pump in my autocross car. Works fine. If noise is too much, you could always turn up the radio louder than the engine/exhaust.
J Bubela

Prop,
I do not speak from experience, as I have only gotten one SU pump total out of 6 or 7 Spridgets I have owned, and that one came in a box of rusty parts in the boot. Arf a mo', Skutterbotch might have one, I have not checked yet. That said, I have had very little problem with aftermarket pumps of the multiple varieties I have had. MGB transmission mounts work well as a rubberized mount for the Facets (you just knew MGBs were good for something!). Important is that the pressure of the output should not exceed 2psi unless you want to use a pressure regulator on it. If so, make sure you get a very good regulator, as the cheap ones simply restrict flow and don't help much at low speed and starve the carbs at high speed.

Back to the SU. The diaphragm and the points are about all that seem to need attention, so I would suggest following Paul W's advice.
David "pretty useless" Lieb
David Lieb

Prop

Some 25 years ago I had a 74 MG midget and replaced the fuel pump with the square box type. I was on a budget! The box type sold by NAPA today looks the same as the one I bought in 19-whatever. As long as its the 2 psi variety, they work fine. Don't have the tick-tick sound, but are very dependable.
I also rebuilt an SU for my MGB as few years ago and it leaked like a sieve afterwards. Turnout the rebuild kit parts were not compatible with gasoline! It was purchased from a regular dealer in the US, but fortunately for them I don't remember who.
Today I'd either go for the new SU or if I wanted to save a little money I'd go for the NAPA square box.

Bruce
B C Hamper

As to the noise of the sq box napa pump...what is the source of the noise,....is it the pump its self making a racket, or is it the vibration that the pump gives off.....

If the valves and coil will still live on for several more years, I guess Ill just order a new diaphram and point set....no scense in re-inventing the wheel....besides Im pretty sure the noise would make me a little edgy after awhile

Im guessing after 25 years the aftermarket companys may of figured out how to make a diaphram gasoline compatable...lol.


prop
Prop

well...that sucks,


Apperantly by the time you buy the points, diaphram, and gaskets...your only saving about $20-$40 over buying a brand new pump ....so certianly not worth the hassle...so looks like its a new pump....least it will be good for another 35+ years


Thanks everyone I really appericate the good advice, personal experiances, and thoughts

prop
Prop

Prop,

As a first option, just try dismantling your own pump and cleaning up the points (as you would with dissy points) / readjusting. Doesn't get much cheaper than that, and may last you for another couple of years until business picks up, and you can afford the luxury of a new pump.

Steve
Steve Clark

Rebuild your original! It's easy, as long as you seal it carefully (wellseal or something, but NOT silicone which has a habit of breaking off and blocking it!) they don't leak and mine has been reliable ever since! Points are easy to change as is the diaphragm, the rebuild kit comes with instructions and you have the proper sound restored!

These should really have a 'service interval' of every 5 years or so..the cost of a rebuild kit is cheap and it doesn't take long.
Robin Cohen

This thread was discussed between 10/08/2008 and 11/08/2008

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