Normalised temperature gauge?

Hi All,
As per the title, is the TF temperature gauge normalised or not? I’m asking as the Jag I’ve got has a normalised gauge (so I understand) and I personally think it’s a bit of a cheap thing to do in what was an expensive car back in the day.
There’s someone in the U.S. selling a Jag kit to remove the normalisation and I wondered if it would work with the TF’s.
For anyone who doesn’t know what this means in this context, this is my understanding of the term ‘normalised’ it’s the temperature gauge essentially has three different positions:
1. Clap cold. Bottom of scale.
2. Normal. Within certain limits. Roughly centre of scale
3.Too late mate. Top of scale.
Or are they all normalised?
Regards,
Michael.

This is an interesting question; do I trust the gauge that the manufacturer gave me or do I not trust them?
Most temperature gauges are crude, a thermistor, a resistor which alters as the temperature changes, a meter movement to indicate these changes & a power source. A basic thermistor embedded in a metal jacket isn’t going to track the coolant temperature with any great accuracy or speed & if the engine temperature rises rapidly & you be concentrating on something else, well it’s too late mate.
I will attempt to attach a photo of a device I’ve been playing with in another area but would adapt well to alarm if the heat exceeded a temperature you preset as your maximum.
These are about £4-00 off eBay & although it wouldn’t pass a Ninas calibration check ie will certainly save a possible catastrophe.
M
This circuit has been modified for my application.

It would have been better if I had given you a more concise indicator than just £4-00 & eBay. W1209 is the ref number I’ve just looked up & don’t worry about it only going up to 110 degrees, once you’re alerted to it getting hot you’ll not forget all that easily.
M

Interesting.
I’ve been working on the widget below. It started life as a two stage fan system for cooling a pair of hi-Fi power amps that over their 25 years had started to suffer from various heat related issues - failing capacitors and transistors. These were all replaced with added heatsinks were required. After seeing a thread elsewhere of someone in Oz IIRC using two 80mm on the engine bay grill to pull air up and out I thought it could be modified to do that. It’s a bit OTT as it stands as there’s 4 pages to display for the temperature sensor readings, set points and an average temperature. Two of the switches are for page up/down, the third for on/off. The single pot sets the set point with a fixed off set for the two stages. Ideally the display would be viewable while driving but the sensors I used are active and use a data link rather than just being a resistive one. Not sure about the maximum length of cable for the data link but not insurmountable.
Regards,
Michael.

That’s a bit more than a couple of pissy little 80mm fans need, mine just come on triggered by the existing engine bay fan.
But if it makes you happy…..go for it

It’s what I used to do for a living - HVAC controls 👍🏻

I used the thermometer illustrated above to monitor the engine compartment temperature whilst trying to decide the valve of supplementary cooling fans fitted in the two 80x160mm slots in the boot lid. Choosing the hottest period of the year so far was in one respect daft, as the background air temperature was high, on the other hand no better time to find out how far the fans could reduce the heat.
The conclusion was in favour of the fans & so I’m on with the job. I’m not initially going to have them thermostatically controlled, using instead a dash mounted press button & using the dual temperature gauges I have mounted adjacent to the ash tray. There’s still some work to do but it appears to work well, moving in total & according to the tech data, some 130cfm.
For those who might want to look at these fans as an option do be conscious that although the aperture in the boot lid suggests it will easily take two fans side by side, the fans are slightly larger & require fitting.

Serious questions and not meant to be seen/taken as nit picking.

I've seen the solution using quad bike fans and am considering it, your solution looks neater but I have two questions.

The fans I presume are designed for electrical appliances etc, will they be up to being exposed in all weathers?

I would think when not on they are quite a barrier to the normal air circulation have you collected any data on temp rise over time before the mod to compare post mod. It would be interesting to find out what difference (if any) the standard vents have on the engine bay temp.

You raise a number of salient points, I do a bit of development work for different applications & as I don’t want to be stuck in the workshop operating a circuit, I use the car as a test bed. This time it’s a switching system which can switch a fair amount of current in a very small package.
Whilst out & about I can run tests & enjoy the car.
I had a mismatched pair of fans which I started with, I then bought a matched set & after a faf they fit nicely. As you can see the job isn’t finish yet & as I’m off on holiday tomorrow I’ll sort it later. I’ll do those assessments when I’m back & ten minutes would see it stripped out if it’s counterproductive, by which time I’ll have done the tests I need to do.
M

I’ll pick up on possible water ingress now I’ve had my tea.
Yes they are cheap electrical cooling fans & as such are far from robust. To mitigate this the contracts have been potted with U/V adhesive & bolstered with sticky backed plastic. I’ve also made a cover to pop over the vent. Earlier whilst having a brew the heavens opened & they were saturated, I stood with my tea watching the cascade for half an hour, when it eased off I switched them on with not a problem.
When the engine had been run for a while the convected heat freewheels the fans but you are correct they will impede the upward flow of heat.
M

My fans have been exposed to all kinds of weather for some years, without any problems.
I did source my fans from off road quad bikes, these things operate in all sorts of mud, muck and extreme conditions.
So sitting in the relative luxury of the engine bay of the MGF should be as easy for the fans as shifting in bed and kicking it out with your feet!
It should be obvious that the fans are mounted fan side up with the hub centre of the fan protecting the motor and shaft from exposure, and equally obvious they the fan hubs are of the blind kind, with out the shaft penetrating though the fan hub thereby allowing the shaft to be exposed to the conditions from above and allowing water to pool in the hub.

As I did this years ago and have had no problems, I really suspect that some of you are making it a bit more complicated than it needs to be, but maybe there is room for improvement.
It may and indeed probably will come as a surprise, and shock to you, that I don’t know everything :omg:……it just seems that way! :bust:

I cannot conceive that last paragraph as being correct, you’re just being bashful & understated, in fact this typifies the Australian character to a tee.
It’s exactly the same outlook as we see with the Australian sportsmen & women, always standing back to allow others to have a crack at the games.
It’s also quite useful if you allow everyone to lead the way; with such a sportsman like gesture the opposition won’t notice you tampering with the ball, picking the seam or giving a the ball a sand.
Oops did I say that out loud?