Clark’s Clock Conversion Kit

[plrgpr]

Installed Clark’s Quartz Conversion Kit in my 66 (Corsa clone) worked fine for two months, then started to quit anywhere after a couple of hours to a few days after the car was parked. Noticed that if I hooked up the battery tender to the car immediately after parking the car, the clock never quit. OK, I get it, a voltage drop after the car was shut down unless hooked to the battery tender. So, if there is not voltage to run the clock, why would there be enough voltage to turn the engine over normally for starting?

[bbodie52]

Try using a multimeter to measure battery voltage after it has been sitting without a charge or Battery Tender connected. See how much the output voltage has dropped at the source. You might then look at the clock connection point and check the voltage there. If the battery voltage at the source is significantly low, there may be a drain on it somewhere in the car or a faulty battery. If the voltage is lower at the clock input than the reading at the battery, you may have a bad connection somewhere between the battery and the clock connector, with a high resistance causing the voltage drop. If the voltage is good at the clock input, but the clock is not operational, you may have a bad ground connection at the clock case caused by a faulty ground in the instrument panel. If the connection to the electronic clock or the ground connection is poor, the clock may "see" a voltage that is somewhat lower than the nominal 12 VDC that it is designed for, and after some discharge time the voltage may drop below the minimum threshold needed by the clock circuitry to function.

The construction of the 1965 and later instrument panels are mostly plastic. The point-to-point ground strap is needed to ground each of the electric instruments and illumination lights.

How well your Corsa or Monza/500 instrument panel works depends on the condition of the ground strap assembly and the grounding connection to the metal dashboard (chassis ground). The ground strap must be tightly connected to the dashboard frame to provide all of the electric instruments, display illumination lights, high beam and turn signal indicator lights, etc. with the required ground return path. The speedometer and manifold vacuum/pressure gauges are mechanical in nature and do not require a ground connection.

[plrgpr]

Brad, thanks for the advice. As usual, you’ve been most helpful. I don’t think it’s a battery problem as the engine cranks over normally no matter how long it’s been setting. Also, I don’t think it is a ground problem as all other guages and dash/idiot lights works perfectly. I’ll be checking voltage at the clock power point next after it sets for awhile, but that means pulling the dash again as I’ll never be able to access the clock w/o doing so…… ugh!
Thanks again!

[bbodie52]

The instrument panel grounding system is fairly simple. On the Corsa instrument panel a single ground strap is attached to a steel instrument sub housing that holds the cylinder head temperature gauge, the clock, the turn signal and high beam indicator lights, and one instrument illumination bulb. If all of those lights and the cylinder head temperature gauge are working, the ground strap to the sub housing that is common to all of those items is likely OK. There is also a 12-pin multiconnector that ties the instrument panel wiring harness to the rest of the vehicle wiring. It is possible that there is a poor, corroded, or damaged internal metal connection inside that multiconnector that could be causing a problem with the voltage that is reaching your clock. The voltage tap comes from the fuse block, and also feeds the dome light, glove box light, etc.







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1965 Corvair Corsa Full Schematic

1965 Corvair Fuse List and Fuse Block