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MG MGB Technical - Fuel pump delivery

Am I correct to expect approximately 3 US cups of fuel per minute from my SU pump? I tested that today and got my 3 cups in about 25 seconds. Is this just a bonus or is the fuel pump going crazy? I don't have a pressure tester.
Steve Simmons

When under no pressure -- i.e., artificial conditions -- they flow much more. No worries. Check the pressure though ... nothing more counterproductive than having too much fuel pressure.the
Ted

Steve - The SU fuel pump for the MGBs should pump 2 pints per minute (see my article on Les Bengtson's web site http://www.custompistols.com/cars/articles/dd_su_fuel_pumps_101.htm)
If you have a vacuum gauge, most of them will read pressure up to about 10 lbs, which is sufficient as the pumps for the MGBs run about 1.5 psi - 2.7 psi. At three cups per minute, your system is a bit on the low side and you need to check if you have a week pump or clogged lines. Cheers - Dave
David DuBois

Actually it was three cups per half minute, roughly. I believe there are 3 cups in a pint, so it sounds like my pump is right on.

Question - Is there a recommended type of gauge to test fuel pressure that won't be damaged by the gasoline? Does anyone have a design for a good interface from fuel line to gauge?

Thanks all!
Steve Simmons

Steve - There are 2 cups in a pint, so at 6 cups/minute (3 pints/minute) your pump is doing fine. The vacuum gauge will not be damaged by gasoline, it is a Bordon (sp?) tube guage with all metal parts. The best way to measure the pressure is to install a 'T' fitting in the line to connect the gauge to, then have the car running while monitoring the pressure.
Good luck - Dave
David DuBois

This thread was discussed on 08/06/2003

MG MGB Technical index

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