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TR 3 temp gage replacement

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Camping57

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Now that I have my car running well I have decided to take care of some of the old 'issues' that I have put off for so long. One of these is to get a working temperature gage. I had a swap meet TR 3 gage that worked only once and I tried a TR 4 gage but didn't know about the voltage stabilizer, so it doesn't work.
I read in another thread about how to rebuild the old capillary style gauges so I went donw to the basement to find the swap meet gage and it is gone! The box that had all my "rebuildable" parts got thrown out during a cleaning episode.
So now I have to try something else.
I am wondering; what do I need to do to get the TR 4 gage working? Right now I have a generic sending unit screwed in and the wire running to the back of the gage. It doesn't move at all, so I know that I need to try something else. I read about the voltage stabilizer, where and how do I wire that in? What is the proper way to hook up the gage wiring?

Dick
 
Right now I have the same set up in my TR3. I am using a TR4 electric temperature guage and other then not looking exactly correct it works just fine (once I got a voltage stabilizer built).

I do wonder about yours though as it should still work without the voltage stabilizer, it would just read hot (that is, the indicated temperature would be higher then the actual temperature).

I suggest your first step would be to confirm the guage and sender work. The sender is easy, as all you need to do is confirm it has resistance and that the resistance varies with temperature. Use an ohm meter for this. I ran an experiment and have the resistance vs. temprature curve plotted if you want it.

Second would be to confirm the gauge works and is installed correctly. The way it is wired is from the battery to the gauge (though there should be a voltage stabilizer between them) then from the other side of the gauge to the sender. The other side of the sender is to ground and that completes the circuit.

If connected correctly and you don't have movement, then check that you have voltage at the battery side of the meter (and that you have the meter the connected the correct way round). Also check the the sender hac continuity to ground.

BTW the term sender is a bit misleading in that it does not 'send' anything. It is actualy a variable resister that changes resistance with changes in temperature. The circuit need power from somewhere else.
 
Here's a link to a thread that discusses the voltage stabilizer. There is also a link to a pdf that shows how it works, and how to build a solid state version. /ubbthreads/images/graemlins/thirsty.gif
 
As mentioned the electric gauge should get power in (preferably at a controlled 10v) the second wire goes to the sending unit which in turn has a ground connection through the engine. Operating without the stabilizer your gauge should read as much as 40% high with the engine running.

As scary as this sounds, you can test the electric gauge by connecting its two spade lug leads directly to the car battery, one positive, one negative. The needle should quickly go toward "HOT". As I said, this is a quick test, don't leave it like this for longer than is necessary to confirm that the gauge works.
 
You know, I got to thinking about this. If you ever plan to go back to an original TR3 capillary gauge, why not just get a new capillary gauge from Pep Boys or someone. I've seen them up there for less then $20. Just make sure it has the same size gland nut at the end as the TR. It's a pretty common size. Then, when you get another TR3 gauge that needs repair, you will be able to use the tube and bulb assembly from the one you got at Pep Boys. That's what I did. I was running a Sun gauge, and when I found the article on repairing the capillary gauges, I used the Sun as the donor for the bulb and tube. I'm sure a non-functioning TR3 temp gauge can be had for a song. All you need is two or three inches of tube coming out of the back of the gauge for you to splice on the new bulb assembly. /ubbthreads/images/graemlins/cheers.gif
 
Heres a link to a knowlage base article that may help
 
Excellent article Banjo! I'll print out a hard-copy of it for my gauge repair files at home.
 
Thanks Guys,
This is exactly the info that I needed. You guys are great!
My plan is to try to get the TR 4 gage working for a short to mid term fix, while I look for either a working TR3 gage or a broken one that I can repair by putting on a new capillary.
Real short term I am stripping wallpaper and repainting my sons room while he is gone this week. Stripping wallpaper is almost as much fun as stripping Bondo, but much less satisfying. No Triumph work until the painting is done.
 
At least stripping wallpaper you won't get a nose full of pink dust!
 
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