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Fuel Pump

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vping

vping

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This just dawned on me. When I was "Awakening" the BGT, I first tackled the FP.
When I got it running it does not come on like I think a pump should. It is not a steady stream but more of a squirt squirt squirt. When I finally got the car running, other than a few minor things it was running fine.

I guess the question is what is normal pump activity?
 
Is it an SU pump? Does it tick? PJ
 
Its an su and yeah it ticks and operates fine to me. It's just that to me it's fine and to others it might not be. I guess if it is running I should be OK I just dont want to breakdown somewhere.
 
That's normal... it's not a continuous pumping action.
 
Kinda what I wanted to hear - literally.
 
Does the car suffer any indications of fuel starvation at speed?
 
Don't know yet as I have yet to get it on the road. Only had it a few weeks and am working towards that.

DMV today for plates & such.
Waiting on Santa Moss to deliver a box.
Tires.
Tunes.
Then I should be road ready.

I wanted to start asking about the FP in case I might be in for a failure soon. The only other SU I have listened to is for my TD and although it sounds the same I have not run fuel throught that one yet.
 
It's a kind of "demand" pump too: as fuel is delivered, and pressure established in the supply side it will slow down the ticking interval. Checking the flow rate is about all you can do to "test" it. With two LBC's you may consider having a spare on the shelf. With a bit of "Creative Plumbing" it'll fit either car. /ubbthreads/images/graemlins/wink.gif
 
I've actually got quite a few but never really thought about flow rate or sound until this point. I have 3 from the midget projects (if they ever go anywhere) and I have 2 in the XJ6. I have a spare for the TD and I have another for the XJ6 which needs a diaprham. All tolled I have lets see 2, 4 carry the 1.... 9 in or out of cars. Plus a few after market ones that were came with the TD with some kinda dial setting to adjust the flow.

What is a recommended GPH for these?
 
I can't remember for the MGs! If you want to stick with original, you might want to consider a rebuild kit, (if you need another project.) I just ordered one for an SU pump, it costs about $80. Or, you may want to consider at least replacing the points.
 
/ubbthreads/images/graemlins/savewave.gif One more thing, lot's of folks recommend 'transistorizing' the pump to reduce the amount of voltage on the points to prevent wear on the points.

Check out the link: web page
 
I personally love my solid state switched SU pump. /ubbthreads/images/graemlins/grin.gif
 
Vping - What the others have told you is correct, the pump is an impulse pump and as such, delivers fuel in pulses or squirts. As for a spare pump that will work on all of your vheicles, the AUF 300/AZX 1300 series pump that is used on the MGB will work on on the midgets also, but the TD takes a AUA 25 pump, also known as a L type up. It is a low pressure pump, whereas the other cars take a high pressure (the AUF 300/AZX 1300 series) and the L type pump will not work for them. It would also take quite a bit of creative plumbing and mounting to get the AUF 300/AZX 1300 pump to work on the TD and then you would probably have to deal with the different polarity on the TD. For information on the volumn that is pumped by each of the pumps, see my articleon SU fuel pumps at https://www.custompistols.com/cars/articles/dd_su_fuel_pumps_101.htm

While a transistorized circuit will help stop wear on the points due to arcing, it will often cause a problem to occur with a film building up on the contacts and insulating them one form the other. Without a transistor in the circuit, the arcing burns the film off and keeps it from insulating the contacts. To be effective, a solid state conversion has to do away with the points completely, either using a Hall effect circuit, a magnetic reed switc in conjunction with a transistor as I use in the conversions that I do, or an optical trigger and a transistor to run the pump.

The best bet for a back up pump, especially on the MGB and the Midgets (where the pump is under the car) is a permantely installed back up pump as described in my article at https://www.custompistols.com/cars/dave/BackUpFuelPump.htm
Cheers,
 
/ubbthreads/images/graemlins/savewave.gif Dave DuBois, when I've looked at these aftermarket pumps, they have included instructions about mounting as close to the engine as possible. Would that be for a bigger car and not applicable to the LBCs, or is it even necessary?
 
Wow great info. I printed these and will read them later at lunch.
 
The only aftermarket pumps that I have delt with are the little, square, run all the time, make a lot of noise, Facet pumps and the plastic bodied Auto Pulse pumps from New Zealand. Both of those types mount in the same place as the original SU fuel pumps do, in the back by the fuel tank. My guess is that the pumps that say to mount near the engine are low pressure pumps (1.5 PSI or less) and are ment to be mounted within 6" of the height of the carburetors. The SU fuel pumps for the MGBs is a high pressure unit that puts out 2.7 PSI and can be mounted up to 48" below the level of the carburetors. A pump that is mounted under the car near the fuel tank with all of the fuel entering the hot engine compartment under pressure, makes things less likely to have problems with vapor lock than one mounted in the engine compartment, with the inlet side being under a vacuum when it enters the hot engine compartment.
Cheers,
 
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