Joined: Aug 2017 Posts: 112 Threads: 25
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I am looking to fit a thermal switch for the electric fan on my trials Chummy. It will go in the hose from the head to the top of the radiator. I wonder what is the optimum running temperature?
The options available are:
On 85C, off 77C
On 90C, off 80C
On 95C, off 85C
I am favouring the middle one, but what experience does anybody have?
Thanks,
Bob.
Joined: Aug 2017 Posts: 780 Threads: 33
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Location: Beautiful Northumberland
Car type: 1933 RP Saloon (aka Mildred)
When I measured the top of my standard road going RP with a thermal imaging camera the top of the radiator near to the hose connection was at 85 degrees, presumably the water was a little more.
Enjoy yourself, it's later than you think!
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A variable one might be better, Kenlowe make one and lots on E-Bay less than £20.
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Location: Scottish Borders
We have an 85C Renault 5 thermostat in the top hose. It works well.
In the winter for normal road use the A7 is overcooled so the fan belt is removed.
Jim
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In my small experience, Bob (s/c road car with no fan, traffic in summer the main reason for the electric fan) it’s quite a good idea if it switches on a little before you really need it. In stop-start conditions things heat up quickly if you are moving slowly and don’t want to keep switching the engine on and off. I would lean towards the lower heat range myself. I also have an override on switch so that, if I switch the ignition off, I can keep the fan running if I so wish.
Regards,
Stuart
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Location: North Yorkshire
Agree with Stuart, Bob. Lower range rather than higher. I've no experience of an electric fan on a Seven but I have with a Meadows 4ED in a 12/40 Lea Francis. That car has no fan and no water pump as standard so thermo-syphon is all there is. An electric fan wouldn't cool the engine down once it started to overheat. However, turning it on when I could see a situation coming where it would overheat stopped that happening. The best example when I had the car was approaching Le Mans on a busy, hot, late afternoon, one September. I could see the traffic building up and overheating was sure to follow. Turning the electric fan on before any overheating started and leaving it running solved that and we arrived at our hotel without issue despite miles of stop/start traffic.
Steve
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Location: Cheshire
Car type: Race Ulster, 1926 Special, 1927 Chummy, 1930 Box
Steve’s right. Radiators have a critical temperature above which the fan will not cool them down and overheating is guaranteed.I imagine it depends on each individual installation, but on my Ulster Rep that temperature is about 90degrees. Switch the fan on above that and it’s ineffective. Switch it on at 85 and all is well.
Alan Fairless
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Thanks everybody! I knew that there would be some pearls of wisdom that I could garner.
I'll go for the lower one then, don't want to cook another engine!!
