Electric water pump combined with the mechanical one, on RCR GT40

[Jean-Marc]

I have an additionnal electric water pump on the cooling circuit in addtition to the mechanical pump of the engine. To inform you, I did not built the car I only rebuildt it, and before me the car never run even a mile.
I allways found this strange, and when I try to use it I am earing strange noise that make me think the electric pump is generating cavitation. On top of it I do not see a great change on the cooling efficiency. I remove the connection to the heater to be shure that all the water flow goes to the radiator.
I run the car for a first track day, the ambiant temperature was very high 36°C or 97°F, and the temperature seems very high on the engine, and almost impossible to decrease when I finished my run.
I am strongly thinking to remove the electrical waterpump to keep only the mechanical because I think that it may slow down the flow an create difficulties to an efficient cooling.
I try to found information on the forum about a similar arrangement but I did not succeed.
Does one of you has someting to share about this ?

 

[JP Verweij]

As you say, you did not build the car,
Could it be that the mechanical pump is just an emty case with just a pulley routing the V belt? Before you remove the electric waterpump.
Usualy they take out all internals but leaving the shaft in place.

Second, what controler is used for the electric waterpump?

In my case I even removed the shaft from the mechanical waterpump and put a freeze plug in, Fully empty waterpump case so my crank now only drives the alternator.
I am running a Davies Craig pump & controler.

 

[Jean-Marc]

JP,
The mechnaical pump is not empty, because I replace the gasket and saw the insight. On the electrical there is no controler only a switch on /off

 

[Ian Anderson]

Probably a strange question but do both pumps push the water in the same direction? Polarity of electric pump causing the pump to try and push the water the wrong direction

Ford 302 makes pumps that are designed to be either for a V belt or serpentine belt and if the wrong pump is fitted this could be causing your problem in that the Ford pump is running in the incorrect direction for the vanes so not moving the water effectively.

Just an idea or two

 

[Jean-Marc]

Ian, its a good question, but there is only one wire on the pump that is connected to the plus, the minus is coming from the chassis. The arrows on the pump are supposed to be in the good direction versus the rotation, but I did not check.

 

[Paul Hendrickx]

https://support.cvfracing.com/hc/en-us/articles/360058972694-Small-Block-Ford-Tutorial

 

[Jerry Irwin]

As Ian stated above...
If you did not build it then take nothing for granted or being correct.
You need to trace the mechanical pump OUTLET all the way thru the chassis up to the ELEC pump and confirm its going in the correct direction.
it may be going in the correct direction BUT is the inlet and outlet around the correct way ?

 

[Paul Hendrickx]

E

Thread 'Waterpump theory'

Jan 2, 2012

Due to the recent posts about Waterpump failures i would like to bring in some pump basics.

In my proffessional career i designed a lot of liquid transporting systems with capacities from 2000 l/h to 100000l/h. A lot of them incorporated centrifugal pumps. This is the same working principe as our wp´s.

Generally this pumps are not ment to create high pressure ( max app 8 bar in multistage pumps) and usually not designed for high suction capabilities ( npsh = net positive suction height = app 5 - 6 m in multistage application). To achieve this the pumps need to have a proper impeller...

• EGLITOM
• Replies: 44
• Forum: GT40 Tech - Fueling, Electrics, & Engine Cooling

 

[Jerry Irwin]

I am probably wrong but your photo shows a craig davies elec pump.?
To my knowledge ( i have had a few in the last 15 years ) these come with 2 WIRES and do not rely on an earth as some people just suspend them on the rubber pipes.
I would therefore suggest that if there is only one wire from the pump then it is not working ?