Last summer I thought I got it working as I had two of the originals and one of them started ticking when I wired it up on the bench.  I spent hours calibrating and such and never could get it to not lose or gain a second every few hours.  Well, after I got it in the car it worked for a month or two and then quit.  (and it may have been draining my battery after that)  So I bought a "Borg" quartz conversion kit.  Put it all together (instructions were decent) and wired it up on the bench.  It keeps perfect time, let it run for three hours just now and it was spot on down to the tenth of a second!  One "winter" project down - well it will be after I put the dash back together. 

Congrats Dave! I bought a clock off eBay, had it reworked and then installed it. It does keep time but like your previous one, it does lose time, about 5-6 minutes a day. I did not go quartz. Maybe next time...

I too went the quartz route last year. It's been in the car all winter and has kept perfect time. Car has been stored on a Ctek battery charger.

My clock didn't work when I got my 79. When I called in about getting a new one, the guy said "Do you want it to be original or do you want it to work?" He prceeded to tell me they would not guarantee the original clock whatsoever! He told me that the original style usually ALWAYS quit or have other problems. While they do work for some people, that is the exception. The only way to tell the difference is that the original second hand  "jumps', while the quartz one is a smooth sweep. This is the fifth year that my clock has been in and has kept PERFECT time all along! Still love the analog clocks in any car best!

Original clocks have a set of points in them, similar to a turn signal flasher. The points opening/closing is what causes the clock hands to "jump", or step, instead of having a smooth sweep. These points are usually what causes the clock to stop working, as they burn over time, just like the points in your ignition system, for those of us with point type ignitions.
The points burning/wearing, and sticking closed is also a big factor in draining the battery overnite, and in several cases, has been the cause of fires in the car.

There are quartz movements that do kinda-sorta mimic the "step" of an analog clock, but the steps are much quicker.

Yep, I do kinda miss the tick tock sound and the mechanical jump, but I'll take reliability and safety over the retro aspect.  No going back now!  Thanks for the info, guys.  

I did the quartz conversion also. Keeps time to the minute!!