So a white wire will have power when the ignition is on? Then stick an inline fuse or CB between that and the switch?

I apologise I'm really bad at this kind of thing.

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Brad Cogan

1977 Triumph Spitfire 1500 'Wray'
1989 Toyota MR2 Mk1b AW11 1600 twin cam
2007 Fiat Grande Punto Active 1.2 'Pepper'

Assuming it's a white wire from the original harness and not from an alarm system or a stereo.

Brad,
That diagram is very basic. A fuse may be assumed to be in the supply line by the people who published it. They seem to be confident that the fan controller is capable of switching the fan current reliably.
When I installed an electric fan I did use a relay. I arranged the circuit so the relay is controlled by either a thermostatic switch or a manual dash switch. I also put a pilot light on the dash in parallel with the fan, so the light is lit when the fan is on. Amusingly since I used an LED as the pilot light when the fan spins due to normal air flow, the fan acts as a generator and the light glows.
All the best,
Paul

Brad,
I don't like the idea of adding a big load like a fan to the white circuit. It does run the ignition. It is better to use the white circuit as the control side of a relay circuit and to take a fused line from one of the brown wires to supply the fan contacts of the relay.
All the best,
Paul

So add a relay that's triggered by the wire from the ignition to allow flow from the brown wire from the battery to set off the fans?

---

Brad Cogan

1977 Triumph Spitfire 1500 'Wray'
1989 Toyota MR2 Mk1b AW11 1600 twin cam
2007 Fiat Grande Punto Active 1.2 'Pepper'

Brad,
Yes that is the idea. Here is a diagram of the circuit I described. For a second fan you would simply connect the second fan to the same spots as the one shown.
All the best,
Paul
Sorry file trouble will work on it



Edited 1 time(s). Last edit at 2017-09-02 01:55 PM by spitfire50.

Both of those modern fans together will pull less than the stock heater motor.

Also note that I recommend an inline fuse since most folks are not inclined to upgrade the fuse box and add runs.

I would normally tend to agree with the "anti change to electric fan" type sentiment regarding any type of issue with a 40 year old car.... BUT - I bought my first spit - 1980 model - in 1980. Car had less than 5,000 miles on it. In the Texas heat (100++ degrees are normal), she tended to overheat easily at anything less than highway speeds (even ran warm there)..... Now - 38 years later, I find myself with a 78. Based on my experiences - one of the first things I'm going to do is replace the original radiator and replace - along with electric fans..... Not because I can - but because I think I should..... A few hundred bucks for peace of mind is priceless as it's going to be my 15 year old daughter's first car.... (can you say "bulletproof" as a spit can be?)

Z

For you go electric and aluminum. Keep it for yourself and by her a tank with a roll cage and a helmet.

Give her the spit in her 30th.



Edited 1 time(s). Last edit at 2017-12-26 02:35 PM by lef2wander.

If the car has not been driven continually, there is a good likelihood of crud accumulating in the rad and block. The 78 should have the later wide rad so it should work well without having to replace everything. But, I understand the issue and perhaps would do the same for my kids.
I have a late 79 with the slant rad and electric fan and other than when the thermo switch died, it has never overheated on me even when driving in high summer heat, in 110 range, regardless of speed. So they do work. If/when I get my 78 on the road, if it has any heat issues I will probably just do me a late 79 style modification - if I can find the pieces.

Dan

Lol. Yes - I’m torn between keeping my daughter safe and giving her something “really cool”. She will also inherit my older Jeep Grand Cherokee when she starts driving. About as close as I can get to a street legal tank.

Before you change anything, the age old question is 'what is your opperating temperature'
You cannot judge your engine temp from the reading on an un callibrated gauge.
You need to verify that the engine IS actually in danger of overheating before attempting to make it run cooler.

This^^
The Spitfire employs a pressurized cooling system that is engineered to operate at up to 240 F
Unless there is coolant boiling out, it's NOT overheating, it's working as designed.
The Triumph temp gages are scaled differently than those used on American cars.
The normal needle positions scare most Americans.

The new wide alloy radiator and twin electric fans are going well.

The fans are wired with a relay and adjustable thermostat. It holds its temperature perfectly even under harsh driving in hot weather (as hot as it gets in the UK). Would definitely recommend it to anyone.

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Brad Cogan

1977 Triumph Spitfire 1500 'Wray'
1989 Toyota MR2 Mk1b AW11 1600 twin cam
2007 Fiat Grande Punto Active 1.2 'Pepper'

The sending unit offered by your FLAPS reads high.

Mine rode around 3/4 before I replaced the sending unit with the original Lucas. Now it's between 1/4 and 1/2.