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SW 240A Fuel Pumps
I've just picked up a pair of the SW 240A fuel pumps off eBay and I'm fitting them into my Kirkham.
http://www.cobraclub.com/gallery/dat..._813x1024_.jpg I'm undecided yet on whether to actually fully plumb them in or continue to use the Holley Red Top as fitted by Kirkham. However, if I do wire them up, how we're they originally intended to run? Did they both run together, or one at a time on a 3-position switch (off-on-on)? From the pictures I've seen of original cars the pumps are plumbed in parallel with only a single feed, which means they aren't connected to provide a reserve from different level pickups in the tank, which has been suggested to me. Thank you, Paul |
They were plumbed as a secondary pump set up from a pickup lower in the tank.
The mechanical draws fuel from a higher point; the 240's are normally off during normal operation. The purpose was, when the tank ran low and the mechanical pump starved, the racer could throw a toggle on the dash to turn on the electrics and make it back to the pits. The plate that has the fittings on the fuel tank would have two fittings, with one drawing fuel lower than the other. |
I'm not saying that isn't correct, but it doesn't sound right to me. Why were there two pumps?
Paul |
Ron,
Were they not rated for continuous operation-like in the GT-40 MK II usage? It's also interesting that the mechanical could pull through the SW's while they did not run. |
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2. I can only guess it was a matter of sufficient fuel pressure....or maybe redundancy. |
two separate feed lines with a Tee on the out let of Mechanical pump. Both 240's run at the same time. This is how my csx 4000 car is,
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And, yeah, the lines were simply joined with a t-fitting at the mechanical pump |
FWIW, two pumps was the way to overcome inertia, we used to do this with the old holley inlines for dragracing. one pump would not cut it to get fuel from the back of the car to the front under acceleration two pumps would provide the volume. i don't recall back then there being high flow pumps like you can buy today.
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Pumps
On my car the pumps were the only way to get fuel, there was no mechanical pump. The pumps ran all of the time, there wasn't a different model or variation that ran all the time on the GT 40's, but only on occassion mfor the Cobra. Pumps were used on 65 GT 350, all GT 40's up to an including the Mark 4.
They were all the same, 240 A, both ran at the same time, a switch with 2 positions, on/off |
Why are they so rare now? SW still makes instruments...
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This is what the pickups look like with the top off the tank. Just like a motorcycle with two heights for main and reserve.
http://img21.imageshack.us/img21/2439/pickupsu.jpg |
Is that an original S/C tank Nick?
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I must correct you all on this topic. The SWs are connected in parallel according to SW's 'Stand-By Installation' instructions. This means only one pump runs while the other is on stand-by should the other pump fail during racing. Both pumps take their feed from the bottom port in the tank and both pumps feed into one 3/8" fuel hose which in turn feeds the mechanical fuel pump. The SW pumps act purely as booster for the mechanical pump so that the 427 does not suffer fuel starvation during sustained high rpm running. This arrangment is clearly shown and described in the SW 240 series installation instructions.
They are operated by a single pole, double throw switch with a current rating of at least 15 amps. The port higher up in the tank is purely for a fuel return line for competition cars fitted with a fuel pressure regulator. The 'urban myth' describing the SW pumps as a reserve tank feed when the fuel tank was low is simply wrong. The 427 Cobra was intended to be a race car and it needed the SW booster pumps mounted near the fuel tank and running constantly to ensure the mechanical pump had sufficient pressure & flow at all times during racing. |
Looks great!
I've also picked up a couple of used SW 240 pumps (mine are not as pretty as yours just yet) from eBay and I've been intending to install them for about 2 months. The trouble is, the ones I have on my CSX 4000 work so well, I fear that I'm making a mistake with the swap! I guess if I install them and they don't work as well as the Bendix style, I can always swap again. My current set-up has the electric pumps running in parallel that feed into a "T" on the pressure ("out") side of the mechanical pump. The mechanical pump draws fuel from the higher pick-up point on the fuel cell and the electric pumps draw from the lower pick-up. I rarely use my electric pumps but when I do, they are both switched from one, single pole switch on the dash. |
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Paul |
Stewart,
Have you got a copy of the SW installation instructions you could post up here? Paul |
SW Installation Instructions
1 Attachment(s)
Paul,
No problem, but I can't attach to this post because the file size appears to be too big. I'll e-mail the files to you.;) Also, I would recommend that you replace the seals, gaskets & diaphram if you haven't already done so. If the rubber diaphram on top of the pump has perished, you will quickly have a trunk full of fuel!:eek: I know someone in the UK who was supplying SW 240 rebuild kits, but will need to dig out his details if you are interested. Regards Stuart |
Hi,
I've spoken to Andrew Booth at GT40 Gold Parts, who has had all the seals and gaskets reproduced. One of the pumps seems to work fine and both switches appear to be in sound condition, but the coil spring in the second pump is broken and needs to be replaced. I will probably just install them for aesthetics at the moment and then rebuild them both next winter so that they can bu fully plumbed and wired in. Thanks, Paul |
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Could you please add this document as a picture on your gallery. This would allow a better resolution/ sizing. Thanks ALF |
So I guess Shelby, Mike McCluskey, Geoff Howard and any other restoration experts I've worked with all had it wrong then and now. I still stick with the two levels for pickup main and reserve. Tee fitting after the mechanical. Never seen a return line on anything till fuel infection.
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