Clock repair/restore

[JLPurcell]

Ron, at ZClocks rebuilt mine with the quartz movement. Smooth action, runs just as the original did for the short time it did. I have not dealt with the other vendors but I highly recommend Ron!

[DougN]

Agreed, Ron refurbished my clock 7 years ago and it still works great.

[240260280z]

Enrique was trying to track down the reason for a little drift in timekeeping he had between his power supply and his car. He asked me about it, but I didn't have the opportunity to delve into the issue. My guess is that the non-quartz clock is just more sensitive to voltage. Doing a refurbishment like ZClocks goes to a quartz movement that is probably less sensitive to the voltage.

Yup, I saw this on Dr240z's Z when working on the clock. It kept perfect time on a 12V power supply on my bench for 2 weeks once calibrated but after putting in the car with 13.5V alternator, I had to re-calibrate. It must be some relativistic effect due to the high speed of the car and time dilation

btw The Cesium clock was just too big for the dash.

[SteveJ]

btw The Cesium clock was just too big for the dash.

Just get rid of the shielding, you sissy.

[Captain Obvious]

Just get rid of the shielding, you sissy.

:laugh: Haha! You made me snort!

BTW - I'm not denying that this phenomenon exists, I'm just saying that Datsun (tried to) took steps to prevent it. I don't have an explanation as to what is going on, at least not a credible one...

My money is currently on Blue's relativity suggestion.

[zclocks]

I was reading these posts and thought I would throw in my 2-c worth. From my experience the OEM 240 clocks are not sensitive to voltage but are very sensitive to temperature and contaminants(oil,dust, metal fatigue). I use two different power sources( power supply and car battery) and I have not seen the difference. What I do see is the minute the temperature in my shop drops or rises 20 degree the 240 clocks start to change.

The OEM clock winds the main spring by a small motor that keeps constant pressure on the spring which drives the gears of the clock. This is all good as long as the spring is new, the gears are clean, and the temperature is constant. The bigger problem is that after 40 years all the moving parts are VERY worn and it's hard to get the clock to deliver better than plus or minus 10 min. per week. Another variable is everyone seems to think oil is required, it's not. This is a short term fix and only complicates the problem.

If you really want to make this clock accurate and reliable you can. What it takes is to disassemble every part, clean, inspect, replace the worn items, and reassemble. NO oil or lubricant. Also, this should be done on a yearly basis. I know this is excessive but this clock is just like your grandfathers pocket watch or wall clocks. Grandfather clocks are accurate and had many moving parts but they were all cleaned inspected, and adjusted yearly for accuracy.

The hybrid clocks, 75-78, have a zener on the power line which regulates to 7 volts so power is not a factor. The quarts clocks have only 4 moving parts that are not constantly moving like the 240 clocks and there is also a zener to regulate power to 7 or 8 volts.

Ok, enough and I assume I'll get a lot of flak from this post.

Ron

(Zclocks)

Edited November 8, 2013 by zclocks

[SteveJ]

To the contrary. I appreciate you sharing your experience.

[Dr. 240Z]

Likewise, Ron, thanks so much for sharing your insight with us.

[Mike]

Ok, enough and I assume I'll get a lot of flak from this post. Ron(Zclocks)

No flak from management. You're well respected in the community, Ron.

[Captain Obvious]

I assume I'll get a lot of flak from this post.

Flak? For what? I think your contribution was nothing but valuable. Maybe the forest was missed for the trees... The differences seen between power supplies on the bench and in-car use may not have been voltage at all. It may have been temperature. Warm bench in the shop vs. cold dash in the garage?

I will refine the zener regulator voltage though. I've been inside three 77 clocks and they all used 5.1 volt zeners. You should be able to operate the clock down to just barely above that point. I don't know about other years, but I would suspect they used the same value on all of them.

Edited November 9, 2013 by Captain Obvious

[zclocks]

Thanks for the support and yes I guess I did miss the forest. Seems that when I input on other sites I get less than a positive response.

Your right about the zener on the 75-78 clocks as they are 5.1 volts. I was thinking of the 2-knob rally clock which has an 8 volt zener.

[zclocks]

Also, just wanted to mention that there was an excellent article in Aug 6, 2008 by E. Bettio of Australia on the 280 clock. I reversed engineered the 280 in 2000 to fix my own clock but this guy put in way to much time, but did an excellent job.

http://www.classiczcars.com/forums/attachments/tech-pubs-howto/23622d1212753644-fixing-your-z-clock-how-fix-your-260z-280z-clock-rev-1.pdf

This is on the classic site and and shows up under " Monkey Man" but he credit should go to Bettio. It's a very good article for those who want to see what the electronics in the standard 280Z clock is about.