TR4/4A TR3 - Tr4 Temp Gauge

[mountainman]

I know this might be a stupid questions., but I have to ask.
Can I use a tr4 temp gauge on my tr3 by using a temperature transmitter and voltage
stabilizer the way it is wired in a tr4???

 

[TR4nut]

yep!

And I don't think its a stupid question, since I was thinking the same thing before I finally found a capillary gauge. If you are very lucky, you can even find an early TR4 dome gauge that is electric, it will look just like the capillary version.

 

[PeterK]

or just change the flat glass to a convex will do too.

 

[MGTF1250Dave]

Aloha,

I concur that it can be done. You can even add the fuel gauge to the circuit with the voltage stabilizer.

My TR3A had an electric temperature gauge when I got it, unfortunately it did not have a voltage stabilizer. With out the a constant voltage to the gauge there are wild fluctuations of the indicated temperature. At highway speed when the generator is producing voltage above 12 volts you get a very high temperature reading. When you stop, and the engine is idling and the generator output voltage drops the gauge shows a very cool engine temp, well below normal operating temp. So, if the gauge acts like this you probably have a faulty voltage stabilizer.

With a convex gauge glass it will look at home in your TR3.

 

[Geo Hahn]

The TR4 gauges have a shroud which I think is removable. Glass can be easily switched from flat to dome if that is needed for a match.

Of course a few late TR3s actually used an electric gauge, with one of those it would be a spot-on match. Thay come up on eBay from time to time.

Mountainman -- do you have a defunct capillary tube gauge? If so and you a not going to use it I might be interested in it.

 

[TR3driver]

Geo, I don't believe any TR3s ever came from the factory with electric temp gauges, even TR3Bs made after the start of TR4 production. Lots of eBay sellers advertise something other than what they actually have (one of them assured me that the disc rotors he was selling were the original size for my TR2!) But the early TR4 electric gauges do look VERY similar, and were a popular conversion even then.

Also worth noting that while the TR4 gauges certainly do need a stabilizer; there were gauges of similar (if not identical) appearance that did NOT need a stabilizer. These were 'balanced' movements, similar to the TR3 fuel gauge; and sold as aftermarket accessories for cars not originally equipped with temp gauges. I have one somewhere, still in it's original display carton.

Anyway, in response to the original question, Yes, it's very doable. The TR4 sender will screw right in where the TR3 sender was, no adapter needed. The stabilizer does need to be grounded, but the original type stabilizers do not care about polarity so you can keep positive ground if you want.

The aftermarket electronic ones do care about polarity though, so if you go electronic, be sure to get one that matches your setup.