240z Jeco Clock Repair (original mechanism - not Quartz)

[gav240z]

Great success, a wah wah wee wah..

A little WD40 and some encouragement and away she went. Not sure how long for, but will let it run a while now.

I was going to do the Quartz conversion on it, but seems a shame if the motor still works.

[gav240z]

So it's been running most of last night (think the missus knocked it early this morning and stopped it because the wiring became disconnected) but it seems to be keeping excellent time and ticking away on my desk (I reassembled it).

Anyway here is a couple of photos as to what I believe stops these clocks. It's hard to see with the naked eye, but you can just see this gear on the underside in my video at around the 6 seconds mark.

I used a q-tip and a bit of acetone to try and clean the dirt / grime off the gear (probably methylated spirits or isopropyl alcohol would be better but it was locked in the garage). So I tried to clean these gears as best I could, then added a very small amount of WD40 to the assembly to help lubricate it. I've heard of folks using sewing machine oil, but oil will attract dirt/crap and cause other issues later, so you want something that will lubricate but repel dirt and crud over the longer term. I'm not sure if WD40 is great for that or not?

Ron from www.zclocks.com recommended marine dry lube. Which I'll have to get from somewhere like JayCar I'd imagine.

I sort of knew it was a stuck mechanism preventing it working because I tried to move the big white gears (be careful not to damage the gears on them as they are fragile, so I just used a finger nail) and it sort of ticked over a couple of spots then stopped again and when I applied power to the motor I could see a tiny bit of movement in the clock, so I knew the motor was probably good, but it just couldn't overcome the friction to move.

I suspect many of these Jeco clocks have a similar issue. However broken gears would be more of a challenge but @monkeyman has built gears for the later style Rally Clocks and 3D printed them, so might be able to help make the gears for these if there was demand.

I did notice a resistor in the assembly so that could be another failure point, but the problem for these clocks from what I've read is dust and in an automotive environment you get a lot of it. The housing isn't exactly air tight sealed between the housing, bezel etc..so that's part of the issue.

Also as an FYI, it turns out the Jeco clocks don't have a points system like the Chevy clock video I posted above.

So can you tell the difference between the Quartz clock and the older style original Jeco clock? For the concourse conscious types:

Yep 2 ways.

1. Listen - The Jeco's original mechanism has a constant ticking. Where as the later Quartz ticks periodically (like every 10 seconds or so).

2. The adjustment knob will feel different. The original spins relatively freely, but the Quartz conversions you can hear the gears spin as you adjust the clock (more resistance).

I'm going to play with a few more clocks I was given in part exchange for some ones I had converted to Quartz a while back and see if I can get them working. It's quite fun waking up old hardware after a long slumber.

If I find a complete dud of a unit, I'll probably try the Quartz conversion on it.

PS: Does anyone have a good method for removing the clock hands without damaging them? I used a business card flat against the face of the clock (to prevent damage to the face) and a credit card to pry the needle off, but it did slightly bend the ring section. You can't tell once it's all back together unless really looking closely, but if there is a way to remove it without damage (I'd imagine a wheel pulley of some sort would be useful). Then I'd love to know!

Photos attached of clock gears under microscope showing contamination issues. Courtesy of @zclocks.

[gav240z]

Well it's been running for more than 48 hours and basically keeping perfect time.

1 thing I should mention is that when you apply power to the motor (with the assembly removed from the housing) if you see any minor movement at all, then it's likely your motor is ok and it's just gunk gummed up on the gears, however if you apply power and see 0 movement inside the gears, then it's probably cooked and you have another problem.

Frankly I'm surprised by how well this clock is working, I felt like I only did a minor clean!

[gav240z]

Just to make sure it wasn't a fluke, I have 3 other Jeco's here (2x 240z and 2x 74 260z clocks).

There all working happily now. First image is the crud that comes off the gears when using the q-tip to clean them (with your favorite alcohol based cleaner).

NB: The black stains on the end... clean until you don't see anymore of that!

Here are the sweet spots to clean (first with alcohol). Then lube with WD40 after.

I applied a very small amount of WD40 just little dabs. Once it's on the gears, I push the gear (big white gear) with my finger (down) - same direction as arrows in this photo and let the WD40 runs through all the gears. Then I apply power to the motor to see if it can spin freely on it's own or not. Once your satisfied the motor is running well and doesn't stop after a few minutes of running on it's own. You can put the clock assembly back together.

So far the only clock I haven't revived is the later 75+ clock. I had a quick look but the internals are different. So will have to read this guide.