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TR2/3/3A TR3 Temp Gauge

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I could shoot myself.

I've gutted and thrown out two dual gauges over the past two years. SURE, I've got some screws and chrome bits but I never thought it would have been possible to repair the darn things myself.

I've got to find another broken one just to try the repair! Congratulations! And thanks for posting your success!

EDIT: This is a follow up question that I should have asked earlier. When you repaired your gauge, was the needle pegged at the left end of the scale or had it managed to drift up to some intermediate indication? I was thinking about this after looking at your picture and reading the repair procedure again. I've seen a number of dead gauges that were already reading higher than ambient temperature. Since these are really pressure gauges, wouldn't that mean that the bourdon tube portion of the internal pressure gauge was also messed up? I'm only asking because I will start looking for one to try this repair procedure on and I don't want to start with one having other mechanical problems. Thanks.
 
Revington TR has brand-new TR2-3 temp gauges (with pictures) on his website that are supposed to be same as original for a lot less than a hundred bucks, if my pound conversion is right..


Bill
 
[ QUOTE ]
... When you repaired your gauge, was the needle pegged at the left end of the scale or had it managed to drift up to some intermediate indication? I was thinking about this after looking at your picture and reading the repair procedure again. I've seen a number of dead gauges that were already reading higher than ambient temperature. Since these are really pressure gauges, wouldn't that mean that the bourdon tube portion of the internal pressure gauge was also messed up? I'm only asking because I will start looking for one to try this repair procedure on and I don't want to start with one having other mechanical problems. Thanks.

[/ QUOTE ]

My gauge started out all the way to the left (90 deg mark). I was going to try to put a little air pressure on the gauge before soldering it up to the donor capillary tube just to see if it worked. Not knowing how much pressure these operate on, I chickened out. Besides, the donor gauge I've had for about twenty years so I just went for it. I did check the donor in boiling water first however.

Another interesting point. The TR gauge has maybe a ninety degree needle swing, and the donor I used had a 270 deg needle swing, yet both registered exactly 212 deg in the boiling water. So, I guess it's all in the gauge mechanism that determines accuracy, and not the bulb and tube section.

Edit: BTW, when I was in Pep Boys yesterday picking up some oil, I saw that they had capillary temp gauges for $17.
 
I thought about the matching of gauges and senders when reading the restoration article. Think back to your chemistry classes and the topic of vapor pressure. These mechanical gauges are pressure gauges calibrated for temperature. If two different gauges (90 deg. swing and 270 degree swing) use the same working fluid in their expansion bulbs, it doesn't matter that their swing is different. Both gauges are measuring the expansion (pressure) of the working fluid/gas at a given temperature. If we don't badly contaminate the fluid in the donor bulb with normal air, the working pressure at 212 will be the same so the indicated pressure/temperature will be the same... regardless of the amount of needle movement each gauge was designed for.

Thanks for the for the information on the "at rest" needle position. That's what I suspected. I passed on an MGB dual gauge because it was reading around 160 with the bulb cut off. I think this was a good decision.
 
Found a temp gauge for my TR3, from Rick in NY. Thanks for the heads up; should have it in a week.

Jim C
 
Thanks everyone for your help on this. I posted the original question for Jim since he was new to the forum. Jim is restoring a very nice looking TR3 and I'm restoring an XK140. As you might guess, since he needed a gauge, he's much farther along in the restoration process than I am. I'm still in the tear down stage or better known as "what the heck did I get myself into" stage. Thanks again. Mac
 
I'd like to thank you for starting this thread. Because of it I was inspired to find a way to repair the gauge I have without the big expense of having to send it out. I fortunatly had a donor gauge, so doing the repair procedure was worth a shot. It turned out well, and anyone who wants to do this repair only needs to spend less then $20 for a donor gauge and about an hours worth of time. /ubbthreads/images/graemlins/thirsty.gif
 
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