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Fuel pump - original vs electric

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bdh911 Avatar
bdh911 Brad Hall
Skaneateles, NY, USA   USA
Just bought my series 3 and PO had installed a performance electric fuel pump that is very noisy. Is there some reason I shouldn't revert to the original style fuel pump? Benefit either way? Thanks!

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ahaugland Avatar
ahaugland Silver Member Alex Haugland
Eugene, Oregon, USA   USA
There are a couple of benefits of a rear-mounted electric pump. In practicality, from my experience, the biggest benefit is that you don't have to crank the engine to prime the pump, though some earlier pumps (probably like what originally came on your series 3) have a built in manual priming lever. The other big concern is vapor lock, where the heat of the engine vaporizes the fuel in the fuel line before it reaches the carburettor, causing engine starvation and stalling issues. Fuel under pressure is much less susceptible to vapor lock, thus the fuel coming from the tank before the pump is more likely to suffer vapour lock. than the fuel after the pump. By moving the pump back closer to the fuel tank, you eliminate that issue. The layout of the Alpine engine, however, isn't likely to cause vapour lock as, the most common cause is proximity of the exhaust to the fuel line and they run along opposite sides of the car. All that said, you might be able to significantly quiet the electric pump by making sure it is mounted with rubber bushings between it and the body of the car. Other than the two issues I mention, you get no real advantage over the mechanical pump. A higher flow rate does you no good unless the carburettors are consuming more fuel than the pump can deliver, which should never be the case with the mechanical pump, and higher pressure only increases the risk of flooding and other problems with the carburettors.

--Alex Haugland
Eugene, Oregon
USA

bdh911 Avatar
bdh911 Brad Hall
Skaneateles, NY, USA   USA
Thanks for the help! Matches what I was thinking. Are there any sources for the original style fuel pump with the glass bowl?

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ahaugland Avatar
ahaugland Silver Member Alex Haugland
Eugene, Oregon, USA   USA
I would think that your best bet is likely to be eBay. There's one listed right now with the priming lever. I don't think anyone is reproducing them with the glass bowl for the Alpine, but I think you can get rebuild kits pretty readily still.

http://www.ebay.com/itm/Sunbeam-Alpine-Original-AC-Fuel-Pump-Hillman-Glass-Bowl-Working-Condition-/171515901193?pt=Vintage_Car_Truck_Parts_Accessories&hash=item27ef24f509&vxp=mtr

--Alex Haugland

bdh911 Avatar
bdh911 Brad Hall
Skaneateles, NY, USA   USA
Appreciate the help.

bdh911 Avatar
bdh911 Brad Hall
Skaneateles, NY, USA   USA
Replacing fuel lines - taking out this electric pump will likely imply fuel line replacement. Were originals metal lines? Any resources for those?

ahaugland Avatar
ahaugland Silver Member Alex Haugland
Eugene, Oregon, USA   USA
I'm not sure whether they were metal or not in the Series 3 Alpine. They are metal on my Mk1 Tiger, but are plastic at least on the Series 5 Alpines. If you opt to remove the aftermarket electric fuel pump, I suspect that you can bypass where the pump was fitted in the original fuel line with a piece of hose (rated for fuel, of course!) which is the easiest solution. If your Alpine uses the same plastic fuel line as the Series 5, you can clamp the hose onto the plastic fuel line with band clamps without any problems.

--Alex Haugland
Eugene, OR
USA

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MGB777 Avatar
MGB777 Tim Smith
Oregon, Illinois, USA   USA
1952 MG TD "The "Abbey"
1960 Triumph TR3A "Patch's"
1975 MG Midget 1500 "Little Bro"
1977 MG MGB "Big Brother"    & more
Is there a problem putting a fuel regulator in-line with a electric pump ??

ahaugland Avatar
ahaugland Silver Member Alex Haugland
Eugene, Oregon, USA   USA
No, there isn't a problem with putting a regulator inline. The Zenith Stromberg carbs want fuel at somewhere around 3 PSI, so with many electric pumps, a regulator would be necessary as otherwise the pressure overwhelms the float valve and floods the carb. That said, if your pump puts out 3 PSI to start with, a regulator is redundant. The advantage of higher PSI is to push more fuel through a thinner line every second, but if you aren't burning that fuel, it doesn't serve a useful purpose. Big V8s woth high CFM carbs, however, often need that higher fuel flow so the carbs are built to handle higher pressures.

--Alex Haugland

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