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Electric fuel pump

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UKPhilTR7
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Electric fuel pump

Postby UKPhilTR7 » 12 Nov 2020 21:46

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Hasbeen
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Re: Electric fuel pump

Postby Hasbeen » 13 Nov 2020 02:00

Phil that pump is totally unsuitable for use with carburettors, without a fuel pressure regulator in the system to prevent the supply to the carbs exceeding 2 PSI.

I don't know why, but I had nothing but trouble with regulators when I tried to regulate our mechanical pumps with a regulator. I tried 4 different regulators, & all of them would suddenly cut fuel supply randomly. Draining the system, & reconnection would restore supply, but this was unpleasant to do on a cold wet night. This did surprise me, as both the Cosworth Ford & Brabham Repco engines I raced both used a fuel pressure regulater with no trouble.

I finally admitted defeat with my current 7, & installed a New Zealand built copy of the old SU 12V pump. They have 4 pumps, offering different pressures from 1 to 4PSI. I chose a 1.5 to 2.5 PSI pump, which very occasionally still causes mild flooding, [just a smell of petrol occasionally, with no noticeable effect on performance], even 10 years after instillation. I chose this pump as others told me of fuel starvation occasionally during spirited driving with the 2.0 PSI version.

As I did not like the idea of crawling under the rear of the 7 on a wet dark night to sort any pump problems, I installed the filter & pump in the engine bay, as low as possible on the inner guard. It has given no problem in its 10 years of service.

The overflow pipes on my SUs are plumbed to waste via a disposable fuel filter. Perhaps if the charcoal filter were still employed it would take care of that occasional whiff of petrol fumes.

Hasbeen

dursleyman
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Re: Electric fuel pump

Postby dursleyman » 13 Nov 2020 11:16

Like Hasbeen says you need a low pressure pump to suit SU carbs, I use one like this on my cars:-
https://www.ebay.co.uk/itm/Facet-Posi-F ... 1974766532

Fitted on the rear bulkhead just in front of the petrol tank.
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Russ

1981 TR7 Sprint DHC & TR7 Sprint FHC
Dursley
UK

http://tr7russ.blogspot.co.uk/

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UKPhilTR7
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Re: Electric fuel pump

Postby UKPhilTR7 » 13 Nov 2020 21:11

Thanks for the replies guys, I am thinking of going down this route as currently I am having issues with my manual pump and the spacer. I cannot seem to stop it leaking, new spacer, with new gaskets and she still leaks. I have changed the bolts for studs in the hope that it would be easier to get on. Nothing I seem to do seems to get the leak to stop so thinking that it may be the way to go to replace it and stop the leak.

With the electric would this help with starting the car? I always find that I cannot start her without having the choke out full. This is both on starts after a week or two or ones that are a day after each other. Would the electric pump push fuel around more prior to starting the engine?
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dmtrmp6
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Re: Electric fuel pump

Postby dmtrmp6 » 13 Nov 2020 23:21

Phil,

As noted by Hasbeen, you need a low pressure 1.5 - 2.5 psi pump for SUs. You might get away with 3 psi, but any more typically results in flooding of the fuel bowls on an SU.

Check out the ECCO Fuelflow range of electric diaphragm pumps with pressures from about 1.25 psi to 10, various flow rates and several styles/size of inlet/outlet pipe. New Zealand origin fuelflow.co.nz, they are a similar design to the traditional su electric diaphragm pump, but manufactured in modern fibre reinforced plastics etc. suitable for most fuels. Readily available here in Oz ($85 - $120). They are also available in the UK (check out powerspark website (simonbbc) and elsewhere on the web/--bay etc.

I installed an Ecco low pressure pump about 5 years ago. Mounted low down on rear of the RHS chassis rail in the engine bay, together with an inline filter before the pump. Power (+ve) from the switched/ignition side of key switch plus an earth (-ve) under one of the pump mount bolts. You can leave the mechanical pump in place (disconnected) to close the hole in the block or use a blanking plate (with a gasket). I will check the pump on the car later today and advise, but I think the model was a 1LM102 or 1LM12. sometimes listed online as designed for morris minor and mini. Critical thing is the pressure rating 1 - 2.5 psi and because the TR7 doesn't use a fuel return line to the tank to circulate excess fuel a relatively low flow rate 1 - 1.5 litres/min.

Since install it has worked flawlessly. No problems with fuel draw, no flooding at the carbs, starts easily (no need to crank the engine over to fill the fuel bowls), just turn ignition on, wait 10-20 secs for the fuel bowls to fill, then start - easy. Like an SU pump, when parked, you can hear the pump running quietly while the bowls are filling - time taken depends on how long since the car was last used. Once full the pump will stop pumping until further fuel required (engine running). If car has recently run (on the day) the fill cycle is essentially instantaneous. During normal operation/driving, the pump is essentially silent.

Rgds, Daryl M

busheytrader
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Re: Electric fuel pump

Postby busheytrader » 14 Nov 2020 10:40

Hi Phil,

I fitted my electric pump in the same place as Russ has. (As recommended by S&S at the time so it pushes fuel from the tank instead of sucking it up to the engine). I protected it from crud with an inline fuel filter and repositioned the redundant heated rear window wiring in my DHC to power it. As an extra anti theft device, I fitted a switch / pump cut out within reach of the driver. I switch on the pump a few seconds ahead of starting the engine to fill up the fuel bowls and it starts instantly. The pump’s ticking noise disappears when the engine’s running.

The Mitsubishi pump originally supplied by S&S has been 100% trouble free for 3 decades but they look ludicrously expensive where advertised now. It’s a low pressure pump but it’s rated above the 2psi max for SU’s. I wouldn’t fit a pressure regulator when you can buy a correctly rated pump.

UKPhilTR7
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Re: Electric fuel pump

Postby UKPhilTR7 » 14 Nov 2020 21:59

Thanks for the information it is pushing me to one thought, that I need to fit an electric fuel pump.

I do like the sound of not having to crank the engine if she has been sat for a bit. I like the sound of turning the ignition on for a few seconds to fill the float chambers and then a nice easy start. It is good to hear that the pump will stop when the chambers are full and not keep pumping.


I think it will be a case of finding a nice pump around 2psi like this one

https://www.ebay.co.uk/itm/FACET-ELECTRIC-FUEL-PUMP-ULTRA-LOW-4PSI-NO-REGULATOR-REQUIRED-4-CLASSIC-CARS-EO/401981239968?fits=Model%3ATR7&epid=12033685639&hash=item5d97f2f2a0:g:eQkAAOSwZ~lZt-kg
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Hasbeen
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Re: Electric fuel pump

Postby Hasbeen » 15 Nov 2020 01:06

I still need full choke to start the 7 in cold weather, & yes even in Queensland it does get cold occasionally. In summer of course the choke cable tends to freeze up due to lack of use.

I have found that once full of fuel, [after running of course], the copper pipe from the tank to the engine bay will syphon the fuel tank almost dry. With the hose removed from the pump, & allowed to droop downwards it will suck all but a cup full of fuel from the tank. This gives adequate supply to allow the pump to be fitted in the engine bay, where you are much more likely to keep an eye on the hoses & filter involved.

Where ever you put it, do make sure that any hose you use is good quality. I had a "Gates" branded hose, previously a top brand, split along it's length, between the copper pipe & the mechanical pump when it was still fitted. The hose was less than 12 months old at the time.

The split deposited 22 litres of fuel on the shed floor in just a week, damaging the front tyres beyond use which were sitting in a pool of fuel. I was lucky the whole shed did not go up in flames. That is when I was told to use, in Oz at least, only fuel hose branded made in USA to be sure of quality.

Hasbeen

UKPhilTR7
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Re: Electric fuel pump

Postby UKPhilTR7 » 15 Nov 2020 21:23

Thanks Has been for the comments, I was wondering if it would be better to put the electric pump at the back of the car by the tank or in the engine bay. It is true what you say that if the pump is in the bay it will be easier to keep an eye on and ensure that the pipes are good and the filters. Also would be slightly easier to get the power to the pump in the bay.
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busheytrader
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Re: Electric fuel pump

Postby busheytrader » 16 Nov 2020 11:04

Hi Phil,

I can see the advantages of both. I relocated my electric pump behind the driver’s bulkhead because it was the easiest and neatest option for me,

The pump is out of the way close to the tank and the existing fuel line on the bulkhead. There’s no exhaust pipe nearby on my single pipe system.

The HRW wire was easily relocated to power the pump via a dashboard switch.

I didn’t have to change or reroute anything under the bonnet, which worked for me since there’s a tubular manifold on each side of the engine bay.

If the pump stops working out on the road then it’s not as easy to check as one in the engine bay. Apart from a couple of basic tools, I delegated my toolbox to the AA man many years ago. :D

I agree with Hasbeen about degrading rubber fuel pipe. I had some expensive braided stainless steel fuel pipe weep close to the carburettor. As well as a faint smell of petrol, the vapours evaporating off the surface made it cold to the touch otherwise it looked sound.

UKPhilTR7
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Re: Electric fuel pump

Postby UKPhilTR7 » 28 Nov 2020 20:50

I must admit that in the engine bay is a better option. I have been looking at the pumps around and I must admit that I do like the idea of this one with the filter and the regulator:

https://www.ebay.co.uk/itm/Classic-Kit-Car-12v-Aeroline-Electronic-Fuel-Pump-Pressure-Regulator-Filter/202685295613?hash=item2f30fc2bfd:g:8CkAAOSwn4ZcQEBe
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dmtrmp6
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Re: Electric fuel pump

Postby dmtrmp6 » 28 Nov 2020 23:50

Phil,
There are many choices out there. Not an easy decision but there is a collection of good advice provided with the series of response posts to this topic.

Couple of highlights:- Pressure regulator is an added complexity (note Hasbeen's comments) and 40 UK gallons (180 litres) per hour is way more fuel flow than you need to feed a pair of SUs on a 2 litre 4 cyl motor for typical use. My engine runs fine with the ECCO pump's low pressure (1.5-2.5 psi) and a 1.5 - 2 litres per minute (90-120 per hr) - no flooding or starvation.

Location (front/rear) today is probably more a matter of personal choice/circumstance today with most modern pumps apparently happy to operate fine in either location. This differs somewhat from the original SU pumps that were mostly rear mount 'pusher' pumps (HP for rear mount) and a small number of 'suction' (L for front mount). Installation of an SU electric in other than there designed for location could lead to flooding or starvation issues. Rgds, DM

UKPhilTR7
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Re: Electric fuel pump

Postby UKPhilTR7 » 20 Dec 2020 21:35

Thanks for the reply guys, I do feel that there Is a need to put an electric pump in. Personally, I think that the option to have the pump in the engine bay is the best option for me, easier to get to if anything went wrong. The regulator is a good option too, but I would have to sort out the carbs though as the one near the bulkhead has an issue and cannot be tuned correctly, it will not go down as low on the garb tune as the one near the rad will. A job for another time replacing the brass bushes.
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