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TR6 Can a TR6 voltage guage be calibrated?

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The needle on my voltage guage sits about 1/4 inch from the left when the car is off and when I start it and run the engine, it is that much too high when running. I have checked the battery when running with my trusty Radio Shack multimeter and it is getting around 13.5 volts while the voltage guage is up to 15 because of the needle. I know that the volts are okay but it bugs me to look at it that way.
 
Sure, it can be done. I did the voltmeter for my Stag last year, which might be a little different cometically but should be the same inside as your TR6.

There are two little round windows on the back, that were originally closed off with some sort of soft material. If you tear the material out (or it's already missing), you should see a slot in each window. The slot moves from side to side in the window (rather than turning) to make the adjustment. The one behind the low end of the scale (left side when you are looking at the face) affects the entire range more-or-less equally; while the other one affects mostly the high end of the range.

It's best, IMO, to calibrate at two voltages within the range of interest rather than at the extremes; so I chose 12v and 14v. Obviously you'll need a voltage source for the two voltages you choose (I used my adjustable bench power supply). Then since the adjustments interact, you'll need to work back and forth, adjusting the LH slot at 12v then the RH at 14 (or whatever you chose). Be sure to allow enough time for the gauge to settle after each change in voltage; ISTR Lucas recommends at least 2 minutes.

I found it difficult to move the adjustments by a small amount without a special tool, so I turned a little pip on the end of a bolt. If you don't have a lathe handy, find a cheap flat blade screwdriver that just fits into the window and file a pip on it.

One of the adjustments was so loose that it would move when I laid the voltmeter on the bench, so I put a drop of Vibratite on it. Blue Loctite would probably work as well.

When you are done, you can stick a piece of tape or similar (I cut circles from self-adhesive labels) to put over the hole to help keep dust out of the gauge. Or leave them open if you're not as anal about a little dust /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
 
Thanks Randall,

You confirmed it, I have to log onto Ebay now. I'll screw that up so bad it'll be giving me Satellite radio signals.
 
Well, good luck on flea-bay. I have 4 of them now (counting the two in the Stags) and none of them bore any resemblance to truth before I started fiddling.
 
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