Dual Stewart Warner 240 plumbing

Planning to use my SW240 pumps I have seen pics of them used in what appears to be in parallel, not in series, I am running tanks that use a crossover tubing instead of a pump for each tank, any thoughts
-Steve
 
I suppose you've found some good fuelproof switches, the achilles heel of these pumps. I'm personnaly looking for a good one for years...

Here is a pic of 1074 engine bay. I've been said that one single pump has sufficient capacity to feed a good hot/street 347 SBF, but if you check the figures, it seems being too short, half the capacity of a blue holley pump. Regarding me, as soon as I can find a good switch, I'll put 2 of them in series
 

Attachments

  • 489218.jpg
    489218.jpg
    258.4 KB · Views: 319
thanks for the post, its funny I though my pumps would need rebuilding until I put some carb cleaner through it and they run like mad afterwards, i guess any degree of lubrication or fluid running thru them and they prefer it over dry running. I am gonna plumb them up and make a rig so they can be tested for leaks over an hour or two, next on the list is a fispa frb11 fuel regulator, yet another unicorn to hunt down
 
Be careful, the real problem is if the pumps have waited a decade or so on a shelf for a new life in your pride and joy's engine bay, the inner switch gasket (not replacable) has probably dried (small cracks in it), meaning it is f..cked up.
The pump will then run dry (or with some carb cleaner as well) correctly, but with some fuel, you could have leaks from the pump body to inside of the switch, where are the electrical contacts, opened and closed by the "actuator pin" (don't know its correct name in English).
Not something you want to experiment... only a good idea during winter, if you're feeling cold in your workshop :drunk:

I've 3 pumps, running perfect dry, but I only trust one switch, which is like new cause it has been lightly used and, above all, continuously since it was made (i.e. the gasket have never dried...)
 

Dave Bilyk

Dave Bilyk
Supporter
Pierre and Steve,
just to clarify;
Two pumps in series give same capacity but twice the pressure.
Two pumps in parallel give twice capacity but same pressure.

the picture in post 2 shows two pumps in parallel.

Dave
 

Ian Anderson

Lifetime Supporter
Do these pumps have built in non return valves? I would presume so.

That said the 2 pumps may be plumbed like that in order to give redundancy / break down protection, if pump 1 fails toggle switch over and second pump takes over and you carry on racing as opposed to being stuck out the wrong side of the circuit wit no fuel in the carbs

Ian
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
The SW240 pumps are a positive displacement pump and yes they have check valves.
I've seen racks of 4 of these pumps on endurance racing Corvettes bac kin the 60's and early 70's although I have to say that I've not witnessed one failing, I have heard of them getting too hot and stopping. I suspect that may have been due to cavitation.
There was one fellow here that managed to machine out old SW240 pumps to install updated pumps inside them. Others may have more information on that.
 
Pierre and Steve,
just to clarify;
Two pumps in series give same capacity but twice the pressure.
Two pumps in parallel give twice capacity but same pressure.

the picture in post 2 shows two pumps in parallel.

Dave

Right ! That was I intended to say, one single should theorically not have sufficient capacity, thus the plumbing on the pic I posted (which I will use, as soon as I could). Typed the wrong word, sorry !
 
Thanks for all the input, feeling much better about using my pumps, now off to find a fispa fuel regulator, will post photo of my pump test rig when fully plumbed
 
Back
Top