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Spitfire Mark III Electric Cooling Fan


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It's perfectly possible to control an electric fan with anything from a manual switch, through thermostatic switch up to absurdly OTT microcontroller doing variable speed by PWM (which is what my Mk3 Spitfire has). There are kits for some of these options.

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I brought a kit locally here in Aus consisting of the temp sensor switch (82C), relay,a make break thermal switch & wiring plus Pete’s hated scotch lock for $24 here delivered its fitted to the daughters Mk2 Spit with a manual over ride switch in parallel works a treat!

I subsequently brought 2ea spare temp switch’s 79c and 84C just in case they were not good quality but pulling one to pieces I’m totally happy with their construction.

So the conversion is relatively cheap.

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4 hours ago, johny said:

Bit confused here as you say manual switch and then mention mechanical thermostat which if working correctly should turn the fan on and off automatically depending on temperature...

Im referring to the original mechanical thermostat installed within the cooling circuit. The electrical fan that has been installed has no automatic way of starting

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44 minutes ago, northernbrowns said:

Im referring to the original mechanical thermostat installed within the cooling circuit. The electrical fan that has been installed has no automatic way of starting

Ah ok because here, at £13.61 incl del., is a suitable adjustable mechanical thermostat switch kit to automatically control a radiator cooling fan:

https://www.ebay.co.uk/itm/191447689025?hash=item2c932be741:g:JaMAAOSw4DJYgiQB

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30 minutes ago, johny said:

a suitable adjustable mechanical thermostat switch kit

That looks like a clone of the Kenlowe unit. Some people find them to be horrid things that cause leaks and nothing but grief. Other people seem to be fine with them.

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2 hours ago, northernbrowns said:

thanks, this is what IM looking for,

Or have a chat with T7 Designs. I've bought my fan, controller etc from them. Very helpful. 

Iain 

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1 hour ago, johny said:

Ah ok because here, at £13.61 incl del., is a suitable adjustable mechanical thermostat switch kit to automatically control a radiator cooling fan:

https://www.ebay.co.uk/itm/191447689025?hash=item2c932be741:g:JaMAAOSw4DJYgiQB

I have fitted one of these with the control knob within reach under the dash and the sensor in the rad return hose. No leaks.

I have gone back to a manual fan though and just set this for backup. It only tends to come on now if weather is hot and I stop in traffic or after enthusiastic driving.

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Hello Mike

                 I use this type but it dose need a boos soldering in the radiator mine is at the bottom on a Spitfire and works a treat but I have 2 small fans so can switch one on first and the second comes on if it gets very hot(not very often!)

T7Design | M22 x 1.5 Radiator Fan Switch Dual Stage 87-79, 88-83c

 

Roger

 

Spitfire fans-002.JPG

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why not just go back to the simple tried and tested (by the engineers at Triumph) mechanical fan. I have never in all the 35 years of spitfire ownership had an issue with the standard setup. Is an electric fan simply a must have that simply isn't needed.

 

Oh well Pete beat me to the same comment

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Is there any other topic that divides the forum 'Big Beasts' like the fitting of electric fans?

Just for the record, I have an electric fan on my Spitfire and it has been faultless for over 20 years. (Triumph Acclaim thermostatic switch tapped into the thermostat housing) Quieter, engine warms up faster, rock solid temperature in traffic. Alternator conversion a must though.

Adrian

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4 minutes ago, Adrian Cooper said:

Is there any other topic that divides the forum 'Big Beasts' like the fitting of electric fans?

Like all things it comes down to personal preference. Do we need it? Or do we want it? If it doesn't make the car any better at least it makes the owner feel better... :)

 

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8 minutes ago, Adrian Cooper said:

engine warms up faster

Maybe a daft question, but why would it warm up faster? Whatever type of fan is used the thermostat will stay closed until the water is hot therefore not passing by the radiator. Is it because an engine driven fan will be pushing air over the engine and cooling it even when the water is cool?

I could be persuaded that an electric fan moves a greater volume of air when it is turning therefore reducing water temperature quicker.

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1 minute ago, Chris A said:

Maybe a daft question, but why would it warm up faster? Whatever type of fan is used the thermostat will stay closed until the water is hot therefore not passing by the radiator. Is it because an engine driven fan will be pushing air over the engine and cooling it even when the water is cool?

I could be persuaded that an electric fan moves a greater volume of air when it is turning therefore reducing water temperature quicker.

I can guess (but can I describe what I mean in a way that makes sense?): the mechanical fan will be working all the time so when the thermostat opens, the warm water coming into the radiator will be cooled from the start, whether it needs it or no, and will take longer to reach full heat throughout the entire system. With the electric fan, the water entering the radiator will be warm, but not hot enough to start off the electric fan until it gets that bit warmer overall. So: the cooling will start that bit later and the engine warms up more quickly. Does that sound right? 

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4 minutes ago, Colin Lindsay said:

I can guess (but can I describe what I mean in a way that makes sense?): the mechanical fan will be working all the time so when the thermostat opens, the warm water coming into the radiator will be cooled from the start, whether it needs it or no, and will take longer to reach full heat throughout the entire system. With the electric fan, the water entering the radiator will be warm, but not hot enough to start off the electric fan until it gets that bit warmer overall. So: the cooling will start that bit later and the engine warms up more quickly. Does that sound right? 

There could be some logic in that, but I would have thought the effect minimal. I'll stick with the mechanical fan and a well maintained cooling system, including a heater that works and can be used as an auxiliary cooling fan 😁

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34 minutes ago, Chris A said:

There could be some logic in that, but I would have thought the effect minimal.

Not minimal at all. The thermostat opens below 80C but the engine isn't really "fully warm" until nearer 95C. Heating up from cold to 80C is quick because the stat is closed, the next 15C takes a lot longer as cold water gets introduced. Having the fan running during this time prolongs that cold water period really quite a lot.

 

57 minutes ago, Colin Lindsay said:

Like all things it comes down to personal preference.

Would that be why two of mine have electric fans but the one with most reputation for overheating still has the mechanical one? No, it's because that's how they came to me. So my "personal preference" is laziness.

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if the car is moving the effect of the forward motion is greater than the fan. So the fan really only gives greater cooling if the car is stationary, and why bother starting the car if you are not going to go anywhere? (or at least similar)

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On this subject, I have been thinking that as a standard fan is said to consumes maybe a couple of HP of engine power (about 1500watts), how can electric fans of maybe 120 to 250 watts shift anywhere near as much air?

I'm guessing that is probably only at max revs though. Possibly at tickover the mechanical fan may shift less air than an electric fan.

As I currently have both fitted I plan to carry out some further investigation if we have any hot weather like we did last year. When it hit the high 30s I put the mechanical fan back on and it did run cooler, never venturing above halfway on the gauge when it had previously registered between 1/2 & 3/4.

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