Electric water pump

[peterd]

Anyone had experience using an electric water pump

[Bob Putnam]

We've used a Davies-Craig unit in an ERA GT with excellent results. The GT presents a challenge in that the system has to push water from one end of the car to the other. At $400 for the pump and thermostatic controller, it seems a bit expensive to gain 15 bhp (and better cooling at idle) though.
Davies-Craig

[peterd]

My main purpose for using the electric water pump was to help with cooling at idle. I am using a MEZIERE billet pump. Without the conventional pump there is no by pass hose. I had planned to run without a thermostat at all, to do this I would need a thermostatic control for the pump itself. I would be interesting in more details on you thermostatic control.

One concern I have is that without any water flow in the block (before pump starts), the engine could endup with hot spot. What temp does you pump start running.

[peterd]

Since my last Email I have some new info. I talked with Meziere's tech department. This is my new plan

1. Put in the thermostat, drill 2 3/16 holes in the thermostat to allow bypass.

2. Meziere told me that the pump should run all the time and not use a thermostatic temp control. As I had suspected having no water flow in the block is a big NO NO. Hot spots will occur because of the location and charactistics of a thermostat sensor.

[Venom S]

I called CSI about this (maker of my water pump), and they confirmed it is best to add several holes if you are going to use a thermostat. Can someone tell me "why" the holes are needed?

Thanks
Venom_S

[peterd]

When the thermostat is closed it blocks water flow. With a conventional water pump there is a small bypass hose that allow limited water to circulate. With the electric pump you must block off this bypass. This means with the thermostat closed the pump will build up pressure in the block and increase the load on the pump. The holes in the thermostat allow small amounts of water to flow, this bleeds off the pressure and allows some water to circulate prior to the thermostat opening. Smaller amounts of water flowing allows the block to reach temp quickly, then the thermostat opens allowing full flow.

[Venom S]

Thank you very much. It makes complete sense now

Venom_S

[Bob Putnam]

The water flow is "throttled" by the Davies-Craig system, so it runs at least a little all the time. No thermostat or restrictor is used. The pump keeps the temperature within a 10F range (adjustable at the dash). It probably requires an auxilliary pump for the heater.

[peterd]

Bob,

So under coldstart conditions do you have any waterflow through the block. i.e. is the pump running

[COBRA427]

Here's what I'm doing:

My motor is an all aluminum LS-6. I originally planned on replacing my stock mechanical pump with a Mezeire electric one (55gpm). One concern I was having was cold weather start up. It's true, you would need to have that electric pump running all the time or face having hot spots at critical areas of your engine, which is not even a good thing. So, during cold climates, it would take longer to warm up your engine.

This is what I've decided is the best approach. I'm keeping the stock pump, and will install an electric booster pump from Stewart. The new pump is installed in between the radiator, lower hose, and the stock mechanical water pump. Stewart does not recommend using an electric pump as your primary pump. Even a mechanical pump at higher rpm's will out flow an electric one.
Here is what I see are the advantages of using 2 different pumps:

1. Your motor warms up as it normally does,as the electric one is not turned on nor needed at this time.
2. Whenever encountering heavy traffic and the temp starts to climb, hit the booster pump. Stewart claims at 750rpm idle, the electric pump will flow 300% more water thru the motor than the mechanical one, thus lowering your coolant temp.
3. After Autocrossing and waiting for your next turn, you can shut your motor off, and just run the booster pump and electric fan to cool down the motor.
My 2 cents.
Ed

[petek]

Ok, dumb question time: if there are no air pockets (bubbles, etc) in the coolant system, how could hot-spots form in the engine during initial start up? It would seem to me (dummy that I am) that the water in the engine would carry the heat away due to convection.

[Bob Putnam]

A small amount of flow, even under very cold conditions, is beneficial because heat is generated in only very limited parts of the engine: The top of the cylinder and the cylinder head. Evening-out the temperature throughout the block warms the oil quicker and allows the block to expand (thermally) uniformly. The intake manifold also may work better when it's warmed a bit. Clearances progress to design specs quicker.

[petek]

Ok, I get it now. The small amount of flow is more to even things out than to keep things cool.

[Schwartz]

Thermatic Fan and EWP
As the owner of a 1984 Ford XE, Falcon, I’ve had numerous encounters of engine overheating when towing my boat on hot days. However, installing a Davies, Craig Electric Water Pump and 16 inch fan has worked like a charm, Installation was a tidy 3 hours . It was simply a matter of removing the existing fan clutch and blade assembly followed by the mounting of the Davies, Craig 16-inch fan to the radiator and connection of the wiring harness provided in the kit. However, with the increased energy required to tow and hence heat rejection by the engine, airflow alone is not adequate to remove the waste heat. Extra coolant flow was achieved through the installation of the Electric Water Pump (EWP) which allows full volume flow of coolant independent of the engine r.p.m. I bought the pump and controller for $450, and it has proven to be a great success with my engine temp now remaining at a constant 88 degrees.