What water temp?

[Iluvspeed]

I'm running a "built" 428 FE in an ERA cobra. I currently have only a manually-operated Span electric puller fan on the radiator. After "dis-remembering" to turn the fan on twice in hot stop-and-go summer driving (Florida Panhandle), I've decided to install a temperature-controlled fan in my car.

I'm going to keep the Spal puller fan. My temp sensor is a probe that will slip into the radiator core. To maximize temp transfer I will use "heatsink grease" on the probe core, and hold it in place with an RTV sealant. I intend to locate the probe in the lower section of the core (428 coolant flow is from the block to the bottom of the radiator.... so I'm mounting the probe in the hottest section of the core).

I'm running a stock FE water pump, and a 16 lb cap. The car is effectively at sea level.

The controller is adjustable. Any thoughts on what temp I should set the controller for?

[FatBoy]

"....from the block to the bottom of the radiator." ???

Are you sure? That doesn't sound right to me. The FE pump on my 427 sucks water from the bottom of the radiator into the engine, out through the thermostat, into the header tank then onto the top of the radiator.

The hot water should always go into the top of the radiator so that it sinks as it cools. It makes no sense that I can see to have it the other way round.

Paul

[patrickt]

The standard ERA method of triggering your fan is to have a thermo-switch in the aluminum connector in the lower radiator hose. That switch triggers at 75 degrees centigrade.

[Iluvspeed]

Originally Posted by patrickt

The standard ERA method of triggering your fan is to have a thermo-switch in the aluminum connector in the lower radiator hose. That switch triggers at 75 degrees centigrade.

Thanks for both of the quick replies! I was aware that the standard ERA configuration measured water temp at the lower radiator hose. Until now, I "assumed" (you know what they say about assuming...) that the lower hose was the hot location.

However, with your comments and the fact that the ERA thermo-switch triggers at only 75 C (about 170 F) tells me it senses the cooler temps--at the bottom of the radiator.

Again, bad assumption on my part regarding the flow direction. Thanks for setting me straight. (As I trace the wiring on my car, it's becoming to me that the prior owner (and constructor) did not use the standard ERA wiring harness. I'm thinking my next "retrofit" will be installing the proper ERA harness along with the lower thermo-switch.)

[cycleguy55]

Originally Posted by Iluvspeed

Thanks for both of the quick replies! I was aware that the standard ERA configuration measured water temp at the lower radiator hose. Until now, I "assumed" (you know what they say about assuming...) that the lower hose was the hot location.

However, with your comments and the fact that the ERA thermo-switch triggers at only 75 C (about 170 F) tells me it senses the cooler temps--at the bottom of the radiator.

Again, bad assumption on my part regarding the flow direction. Thanks for setting me straight. (As I trace the wiring on my car, it's becoming to me that the prior owner (and constructor) did not use the standard ERA wiring harness. I'm thinking my next "retrofit" will be installing the proper ERA harness along with the lower thermo-switch.)

You can use the probe-type sensor that goes in the radiator fins. Typically they're installed 1.5-2"

Derale controllers are common / popular, and this model ( https://derale.com/products/electric...8758585-detail ) says to install it as follows:

THERMOSTAT PROBE INSTALLATION

1. The temperature probe must be inserted into the radiator core between the fins. The best location is close to the water inlet near the radiator tank.
2. The probe should fit tightly in the radiator fins and should not extend past radiator core more than 1/4”.

There's more, but your controller should come with instructions. Alternatively, you can go to the link above or another and download instructions.

[Iluvspeed]

Originally Posted by cycleguy55

You can use the probe-type sensor that goes in the radiator fins. Typically they're installed 1.5-2"

Derale controllers are common / popular, and this model

Thanks. I purchased the Derale controller a few days ago from Summit Racing. Quick delivery. I intend to check calibration tomorrow with a pan of hot water and an accurate digital thermometer I probably will install it early next week. Easy-peasy....!