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MG MGB Technical - Twin fuel pumps

I need to fit a second fuel pump in my Roadster as a standby, for rallying. I have recently fitted a new electronic SU pump and can either fit another one of those or a Facet pump. I have previously fitted 2 Facets in series, with a changerover switch in the cabin, but am not sure if you can do that with SUs. Does anyone have any experience/configurations of twin SUs and/or SU + Facet in series or parallel?
Graham Gilmore

Graham - See the article, Backup Fuel Pump in the SU Fuel Pump Articles on my web site at: Any questions, contact me direct at the e-mail address above. Cheers - Dave
David DuBois

Graham. I fitted up the SU (primary) with low pressure Facet back up, as Dave describes in the article. Only had to use it once, but the piece of mind is great.

Les Bengtson

Many thanks Dave, excellent articles and advice. Looks like I will go for the dual Electronic SUs.
Graham Gilmore

Dave, what is the thread used in the AZX1307EN inlet and outlet ports. I want to replace the banjo connections, but get them from my local hose supplier.

PS. I have decided to use a Facet pump and the existing SU.
Graham Gilmore

Graham - The inlet/outlet port threads are 3/8 BSP. Cheers - Dave
David DuBois

Many thannks Dave. One more, I plan to connect directly to 5/16" hose using a 3/8 BSP adaptor with hose tail. Should I use a taper or parallel thread and will I still need the rubber 'O' ring?
Graham Gilmore

Graham - The adapter should be a 3/8 BSP parallel thread and the adapter should have a shoulder on it to engage the 'O' ring seal - see Fig. 16 & 17 in the chart, Fuel Line Fittings in the earlier link I provided. Unfortunately, I was unable to find a source for these fittings. Burlen Fuel Systems doesn't carry them. They are used on some of the other cars, such as Austin Healey, Jaguars, Aston Martins and Bentleys. A perusal some of their parts sources might turn up the fittings. A taper pipe thread should not be used as over tightening it cold split the alloy casting. Cheers - Dave
David DuBois


Your local hydraulic and general purpose should have appropriate fittings.

Herb Adler

Thanks Dave, you have confirmed the conclusion I came to. I will go to the local hose specialist that I use and hope that the helpful guy is on the counter.
Graham Gilmore

Thanks for all the input guys, pleased to report that the twin fuel pumps are up and running with the silver top Facet before the SU. Was able to get exactly the fittings that I needed at my local supplier.
Graham Gilmore

Graham - "Was able to get exactly the fittings that I needed at my local supplier."

Who is your local supplier and do they have a web site and do they do mail order to the US? I often have people ask where they can get such and such fitting as anything with BSP is generally not available on this side of the pond. Cheers - Dave
David DuBois

This thread was discussed between 28/08/2010 and 11/09/2010

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