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Electric fuel pump straight 6 engine

Posted: Tue Sep 18, 2018 12:45 pm
by philynnbob
Instead of trying to reinvent the wheel :D
Not found in search.
Has anyone running a straight 6 engine with triple SU carbs,replaced mechanical fuel pump with an electric one?
Without the need of a separate pressure regulator.
If so any info would be gratefully received.
Thank you
Phil

Electric fuel pump straight 6 engine

Posted: Tue Sep 18, 2018 12:49 pm
by philhoward
I think the only one that will be OK is - funnily - an electric SU pump.

Electric fuel pump straight 6 engine

Posted: Tue Sep 18, 2018 12:56 pm
by philynnbob
philhoward wrote:
Tue Sep 18, 2018 12:49 pm
I think the only one that will be OK is - funnily - an electric SU pump.
Yes :D
But which one will feed the triples throughout engine range maintaining 2.5 psi
Or am I having a senior moment again!

Electric fuel pump straight 6 engine

Posted: Tue Sep 18, 2018 1:18 pm
by Oaksey
Go on Burlens website and see what similar set ups use. I have a feeling a twin low pressure pump will be what you want

Electric fuel pump straight 6 engine

Posted: Tue Sep 18, 2018 1:19 pm
by philhoward
You might find an MGB one will suffice (assuming it’s the same one as used on an MGC)? An MGB one runs an Essex V6.

Electric fuel pump straight 6 engine

Posted: Tue Sep 18, 2018 1:23 pm
by halfpenny
Try a double SU pump as fitted to Astons; expensive, but does the job.

Electric fuel pump straight 6 engine

Posted: Tue Sep 18, 2018 1:54 pm
by Joe.
I'm using an MGA / MGB one on my straight 6. AZX1331

https://www.ebay.co.uk/itm/SU-FUEL-PUMP ... Sw43haKpwR

Electric fuel pump straight 6 engine

Posted: Tue Sep 18, 2018 5:26 pm
by Old and Slow
660XYB uses the standard SU pump for the three DCOE40 Webers at 2.5psi and is fine. the fuel pump switch is two-position, connects to one or two pumps, but the second pump is on the return feed back to the tank!!
I get around 15 mpg.

Electric fuel pump straight 6 engine

Posted: Wed Sep 19, 2018 3:25 am
by AllingtonGT
I have triple Stromberg 97's on a flathead V8 that uses a progressive throttle linkage, so runs on the middle carb most of the time until you press the throttle which brings fore and aft carbs in to use. The differing cams means they are all fully open at full throttle. It's rare that I get the car fast enough to trouble the outer carbs. They were supplied by a front mounted SU pump through 3/16" copper.

The Strombergs are perhaps more sensitive than SUs to over-pressure and pressure fluctuations. Whilst the SU pump when checked provided the required 2.5psi, the constant pulsing seemed to upset the needle valves in the fuel inlet to the float bowl. The carbs leaked fuel from every joint and gasket and numerous rebuilds did not solve the problem. The heat generated by the flathead seemed to complicate things further causing vaporisation, but at least it meant neat fuel didn't run down the engine too far.....

Over the Summer I've changed the system. I tried fitting a new mechanical pump but that was a retro step in every department. It has to be left on the engine, but is now an ornament.

Taking advice I fitted a red top Facet pump at the rear, delivering at about 7psi and a regulator at the front set to 2.25psi. Fuel is delivered through new 8mm copper pipe front to back. I replaced the original brass and copper carb connections with banjo joints and 8mm rubber pipe to reduce vaporisation through heat sink.

What a transformation. The car starts more easily and is a complete delight to drive. The carbs (almost) aren't leaking at all, albeit I do have a few of the gaskets that suffered under the original system, so need changing again. The ability to adjust the regulator is very useful and I'm sure I will experiment with different settings. Knowing now that it delivers a constant 2.25psi is progress and it has made a huge difference to the way the car operates and runs.

I already have a similar set up on 359 JUA feeding the triple 40's, and that just works. I haven't checked the pressure it's set but feel sure it's about 2.5psi.

Electric fuel pump straight 6 engine

Posted: Thu Sep 20, 2018 10:56 am
by philynnbob
Oaksey wrote:
Tue Sep 18, 2018 1:18 pm
Go on Burlens website and see what similar set ups use. I have a feeling a twin low pressure pump will be what you want
Emailed Burlen,reply here for future reference for others.
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AA7F8DA2-F897-48A4-A6C6-6DB857BCF230.jpeg (142.78 KiB) Viewed 423 times
Now ordered :D

Electric fuel pump straight 6 engine

Posted: Sat Sep 22, 2018 9:40 pm
by Old and Slow
Hi Phil,
Your query got me thinking:
The Sabre Six has an LCS-type electric fuel pump; I've measured the pressure and it is 2.5 psi. The Burlen website tells us the pump can supply up to 12.5 gallons per hour.
I reckon I'm getting an average of 15 mpg at an average of 45 mph, which means a flow rate of 3 gallons per hour. At top speed this might be doubled, to say, 6 gallons per hour, well within the capability of the pump.
Note though, the fuel pipes are 3/8" or 10 mm, which shouldn't restrict fuel flow.
I hope this helps.

Electric fuel pump straight 6 engine

Posted: Sat Sep 22, 2018 9:47 pm
by chrisgallacher
How do you measure the pressure out of interest Philip?

Electric fuel pump straight 6 engine

Posted: Sat Sep 22, 2018 10:15 pm
by Old and Slow
I bought a fuel pressure gauge from Demon Tweeks:
https://www.demon-tweeks.com/uk/fse-in- ... ge-243255/
I also bought the adapter which fits in a length of hose.
Out of interest, the gauge isn't zero'd properly, it reads 1 psi, so is capable of measuring negative pressures!
I checked the calibration against another gauge I have, 0-60 psi (a bit insensitive for the lower range of the fuel pump) but it showed the gauge is accurate.
It isn't permanently installed, so let me know if you want to borrow it