How hot should I run my engine?

[MercuryMarc]

Ok - the radiator saga has nearly ended - after the near meltdown at Hot August Nights in Reno, I replaced my old 2 row brass unit with a 2 row aluminum racing radiator, a 14 inch pusher fan, tranny cooler, Tefba filter, proper 16 lb rad cap (was only 7 before), 170 degree thermostat, analolg water temp guage, and an temperature sensing automic fan switch. The temp that activates the switch is adjustable. The current settings trigger the fan at 205-210 degrees (can get there by idling 15 minutes in the sun) and goes off at 185-188 degrees after a few more minutes if idling with the fan engaged.
Any suggestions about adjusting the set points for the switch?
Thanks for all the help so far!!!
Marc in SF
63 Comet Custom Convertible, 200 ci 6 cylinder '69 Falcon engine/C4
http://mercurycomet.net

 

[MustangSix]

On an EFI car 195-205 degrees is fine, but may be too hot for a carbureted car. I'd set it to come on at about 190 and off at 180 on your car.

Mine comes on at 195 and off at 180. It just takes some trial and error to get the settings that work best for you.

 

[MercuryMarc]

Thanks Jack!
I need to wait foar another warm Autumn day her in SF to try the new settings.
-Marc in SF

 

[MustangSix]

Antoher thing; when you shut down a hot car, the temps can continue to rise and on a good hot day it can cause the fuel to percolate out of the carb and fuel line. Not a problem on an EFI car because the fuel system is closed, the pressure is higher, and the fuel recirculates back to the tank, but on a carbed car, the heat could lead to vapor lock or hard starting.

One strategy that helps, if you have enough batttery capacity, is to hook the relay so that it will continue to run after shutdown. This reduces heat soak, but could kill your battery if it were to run too long. I suppose the best thing is to install a shutdown delay relay to allow the fan to run only a preset period of time after engine shutdown. Even just a minute or so would be good.