Cooling flow layout with electric water pump help

Hi All. Im looking to fit a davies craig remote type Water pump up the front end of my SPF 40. Attached is a diagram for the SPF cooling system. Upon deletion of the mechanical pump , I need to reroute pipework that would normally go to the 2 smaller water pump outlets on top of the pump. I know I need to delete the bypass hose and run a thermostat with a few small holes in it (or a restrictor). Im not so sure about the other connection shown as Connection A on the header tank. I was thinking I should tee into the main coolant pipe flowing from radiator and direct this into the expansion tank outlet A. This is shown as the blue line I have substituted.

Does this sound correct ?

Cooling System Diag2.jpg

Bill Kearley

GT40s Supporter
Filling the system through the expantion tank, line A then to the lower water pump inlet or the blue line will work just fine, just remove the remove line, one or the other. I used a rad purge line at the rad, same as you but installed a petcock and a 3/8 line long enough to reach a pail for air bleed and filling purpose only. No need to run back to the tank. The engine purge/airbleed should come of the engine at the highest point possible, again I used a petcock and a short hose as ness. The last thing I would do is to run the overflow line into a recovery tank. I don't think an open overflow line is legal when on a track.

Howard Jones

GT40s Supporter
I have a Davies Craig EWP on my SLC that has a SBC in it. (not lsx) I have it plumbed exactly as you propose with the following exceptions.

1. I do not have a heater core (no heater system in a track car) so the two heater lines you show do not exist.

2. I used the engine port that you have shown going to the heater core as the port for the purge line. That is a good spot because it is at the highest point on the engine.

3. The Davies Craige EWP systems that include the electronic controller will regulate water flow therefor no thermostat is used. I used a 3/4 inch hole restrictor stainless plate 1/16 inch thick in it's place. I would NOT use a similar plate with "several little holes in it" in it's place. That will introduce turbulence in the flow that will aid in air bubble generation. I don't even think that a restrictor is necessary and I intend to try the system without it eventually as a test.

5. I used the DC OEM water pump replacement manifold kit and attached the EWP pump directly to it. This seamed to be the best location for me.

6. I have a catch tank attached to the overflow line (required on a track car). It holds about a quart and a half and it is vented overboard at the rear of the car behind the rear wheels.

I am very VERY! happy with my DC EWP system. I think it is a perfect match for a mid engine prototype with a V8. I have aprox 500hp and the system never varies from the programed temp at speed. Then only at rest/low speeds if I forget to turn on the fans.
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Howard Jones

GT40s Supporter
Here's a few pictures. The last one in the expansion tank. You can work out the line coming from the inlet line to the pump going to the bottom of the tank.

important note: The expansion system output hose port that goes to the expansion tank port should be located at the lowest pressure point in the system. This is directly in front of the pump impeller. It is also the coolest point in the system. You can see that I have my expansion hose about 3 inches away from the pump input side.


[QUOTE = "Jason Lycett, Beitrag: 532852, Mitglied: 10846"] Hallo alle. Ich bin auf der Suche nach einer Davies Craig Remote-Wasserpumpe am vorderen Ende meines SPF 40. Das beigefügte Diagramm zeigt das SPF-Kühlsystem. Nach dem Löschen der mechanischen Pumpe muss ich die Rohrleitungen umleiten, die normalerweise zu den zwei kleineren Wasserpumpenauslässen oben auf der Pumpe geführt werden. Ich weiß, ich muss den Bypass-Schlauch löschen und einen Thermostat mit ein paar kleinen Löchern (oder einer Drossel) betreiben. Ich bin mir nicht so sicher, ob der andere Anschluss als Anschluss A am Sammelbehälter angezeigt wird. Ich dachte, ich sollte in die Hauptkühlmittelleitung vom Kühler abführen und diese in den Ausgleichsbehälterauslass A leiten. Dies wird als blaue Linie angezeigt, die ich ersetzt habe.

Klingt das richtig?

Vielen Dank! View attachment 96695 [/ZITAT]
hallo ich finde das überflüssig
Thanks for the replies guys. Sound's like my proposal will work just fine.

Howard. Im planning to run without the controller (just controlled via a dashboard switch and off the ignition circuit.) I was advised by DC to try a thermostat with 2 off 5 mm holes in it, so I might try that first. Im also contemplating deleting the heater. Even in the UK I would only drive the car when its mild or warm and from past experience with my old Gt40 they get very warm very quickly so no need for a heater. I also thought not having the hot pipes running into the car would further help prevent cabin getting warmer earlier!

Ive also purchased a Davies Craig water pump block off plate specially designed for the Windsor engine so that should make it easier. Yes a drain pipe (petcock) sounds a good idea at this stage.

Thanks for the advise !

Howard Jones

GT40s Supporter
I think that the controller is worth the extra money. Especially for road use. The beauty of an electric pump system is it does not rely on engine speed to control the water volume circulated. It can run at a speed that is efficiency for the pump design. Controlling the pump speed electronically by sensing what the actual water temp is and using a target water temp to continually vary the pump speed is the best idea since sliced bread.

In any case, the small holes they want you to use is necessary on a SBF when you delete the water pump and the small bypass hose. The water in the engine needs to circulate somewhat so it warms up evenly and until the thermostat begins to open. Your proposed system will run the pump at full volume and rely on the thermostat, and the small holes, to control flow through the engine. I guess it can work but I have to wonder if you will get big swings in water pressure. I would think that it would hard on the pump as well. What did DC say about using a thermostat on a road car and running the pump full on all the time. Especially as it relates to pump life.

When I talked to a different electric pump maker they said that it was OK to run the pump full on in a race car that had high thermal loads all the time. We didn't discus road use so I really don't have a informed opinion, but it's something I would want to know if I was using mine for a road car.
I have the expansion "header" tank with the very bottom engine purge hose fitting (B in photo). With my mechanical water pump with having a pump to intake bypass hose. Is it necessary to use the engine vent component? If no, to I simply cap the tank nipple?. If yes, where is the fitting attached to the top of the engine?
Thanks in advance.

Howard Jones

GT40s Supporter
I would say that the more vent points you have in your system the better the air in it can return to the expansion tank. So with that in mind I would say that an engine vent would be a good idea. The important point is that you need to try and visualize where the highest point(s) in the engine might be. This can be more than one place such as the back of the heads (if the motor is mounted nose down) or just the one. The basic idea is to vent any pocket of air anywhere in the system that might prevent coolant from circulating properly.

I would at least vent one of the intake manifold ports at the front of the intake that are used for temp sensors and attach the other end to your "B".

In the second picture above in post #4 you can see all the vent lines as well as a couple of water temp sensors that have been located in the empty thermostat housing. This would be different in a SBF as the picture is of a Chevy.