Joined: Oct 2018 Posts: 91 Threads: 23
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I'm thinking of fittingĀ an electric fuel pump . I know that SU pumps are good bits of kit, but they are a bit large in the engine bay. Has anyone used a smaller modern pump, which could be tucked away out of site a bit more easily?
Thanks
Joined: Aug 2017 Posts: 261 Threads: 1
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Steve, I haven't used a small modern pump with a Seven but I have some experience, both first and second hand, of the modern Facet-type pump in other machines. If you use such a pump you will need to be aware of how much pressure it produces. If you are using an SU or other conventional carb. such as a Solex or Zenith I would hesitate to use a fuel pressure much over 1 or 1.5 psi. With the vast majority of the modern pumps I think you will need to use a pressure regulator as well to achieve this. You should be able to find a regulator that will go down to a low enough pressure but they are not all able to do this.
As you will have gathered from the first sentence, my preference is to use an SU pump with the sort of carburettor we favour, choosing an appropriate SU pump for its location.
Regards,
Stuart
Joined: Aug 2017 Posts: 1,191 Threads: 71
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Not knowing the model of car that Steve has, I cant make a specific suggestion. What I can offer though is a location that I used on an 'Ulsteroid' that I built some years ago where I mounted the SU pump underneath the rising floor under the passenger's feet. That worked well and was completely concealed..
Joined: Aug 2017 Posts: 1,642 Threads: 23
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Location: The village of Evenley
Car type: 1934 Austin Seven RP Deluxe
Another thing to watch, If I remember correctly is that some electric pumps are mounted at the tank and and have more blow than suck (if you understand my use of technical terms) while others are mounted at the engine end and have more suck than blow!
Joined: Aug 2017 Posts: 926 Threads: 22
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Location: Near Cambridge, UK
Car type: 1928 tourer (mag type), short chassis Gould Ulster
I worked on a car recently which would not run properly. It had a Facet pump at the rear and a pressure regulator just before the carburettor. The problem proved to be the pressure regulator, so the owner intends changing to an SU pump without regulator.
Joined: May 2018 Posts: 2,106 Threads: 110
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Location: Llandrindod Wells
Car type: 29 Special, 30 RK, 28 C Cab
Hi All
I had a facet type pump and regulator on my first special. It still was prone to spewing fuel out of the float cover every now and again. Also I think most of these pumps are 12 volt?
Cheers
Howard
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Location: Darkest Bedfordshire
SU pumps are very reliable. The only issue I've experienced is a tendency for the points to stick after a long time standing unused.
I mount mine on the lower bulkhead but as Hugh suggests, no reason not to put under the floor if appearance offends. If so I'd consider shielding it from road spray.
Joined: Aug 2017 Posts: 1,977 Threads: 90
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Location: Ripon
Having used both Facet and SU pumps I would go for the SU. I fitted Facet pumps on both the Pembletons I built, one pusher near the tank (a pain to replace if necessary) and a puller on the bulkhead with a regulator, both easily accessible. However the Facets are NOISY, the SU I fitted on another car was very quiet until it was time to fill the tank which was a handy reminder.
If your carb is set up for gravity feed from a bulkhead tank the low pressure of the SU may suit it better.
Joined: Oct 2018 Posts: 91 Threads: 23
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Thanks for all the useful replies. I have a chummy scuttle tank gravity feeding an SU carb. The only slight niggle is that when the fuel gets low, there's fuel starvation at the carb, resulting in uneven running. Top it up, and away it goes fine again. I gather its just a bit of a lottery- some cars seem to run absolutely fine with this set up, mine has this issue.
I will take the advice, and have a look at getting an SU pump.
Cheers
Steve