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MG MGB Technical - MGB uprated fuel pump options
|My '77 B is running a 45 DCOE and a 'cube' facet fuel pump. The pump is mounted next to the mounting spot for the original fuel pump running up hill at 45 degrees as per the instructions.|
This pump doesn't seem to have enough 'suck' and eventually stops finding any fuel after sitting in traffic for 5-10 minutes.
I'm looking to upgrade the pump (again!) and looking for suggestions as to which pumps are best and where to mount.
|What about a SU AZX 1307? That is the OEM pump for a MGB and can be had in either the original points style (works great if car is driven on a regular basis) or as an all electronic version (for cars that are not driven regularly). It will mount in the original location for the fuel pump in a 77 MGB - through the front bulkhead of the trunk (the original cover to be placed over the end of the pump sticking into the trunk was saved wasn't it?). The SU pump is quite capable of supplying the 45 DCOE on a standard B series engine.|
I would suggest that before you run out and purchase a pump, you do some diagnostic tests to find out why the Facet pump is not supplying sufficient fuel (they are quite capable of doing so). First of all, when the fuel supply tapers off, hop out and remove the fuel tank filler cap. If you hear a whoosh of air when you remove the cap, you have found your problem - the filler cap vent hole is clogged. If that doesn't solve the problem, then do the tests covered 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
|There is also a red top facet that is cigar shaped and is for cars up to 150bhp from Moss Europe|
|That facet must be faulty, or there is debris in the tank it is sucking onto the pickup sock. The original pump should deliver at least one Imperial pint per minute and in practice it will be more that double that, that's enough to empty the tank in well under an hour! No engine needs any more volume than that.|
|The tank was new around a year ago so should hopefully be free of debris. Talking of the tank vent I have heard the 'whoosh' when stopping to fill up so cleaning the vent may well be worthwhile.|
The red top or similar is the pump I have my eye on as it has quite a decent dry prime height.
|"The original pump should deliver at least one Imperial pint per minute"|
That would be the pump used in the very early MGBs (up to 1964 0r 65). The AZX 1307 used in all the later MGBs is rated at 2.4 pints per minute or 18 gallons per hour. The Facet cube pumps are rated at 15 - 17 GPH.
|I've been running a 45DCOE on my '71 B/GT for decades while |
feeding it with the original SU pump (clicking points and all)
without much of a complaint.
When I say the "original" SU pump - I mean that, literally.
It is the pump that came on the car went I bought it new
I like the SU unit because it is fairly reliable and is rebuildable.
I will admit that on rare occasion I've had to whack the pump
a few times to get it to work after 2-3 of months of sleep;
and through the years I've had to replace the reed valves a
couple of times, and I've replaced the diaphragm only once.
I did later add a diode to the circuitry to minimize wear on the
I tried a Facet pump a few years ago but I found it to be too
noisy for my tastes and it failed in short time. It was still
ticking, but it wasn't flowing any fuel. The Facet pump went
into the trash and the original SU pump was put back in.
|The SU unit was also fitted to the factory V8. I suspect you have found out the hard way why many installations comprised a filter before the pump as well as after. I have been stopped by filter blockage on two occasions, the first was crud, the last time was labrador hair - yellow not black !|
This thread was discussed between 28/06/2012 and 29/06/2012
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