I have done a search and didnt see a related thread specific enough for the clock. Have a 47 Ford that has been converted to 12V with SBC. Wanted to use a Runtz for the original clock but I am concerned that the clock was made for positive ground and the Runtz specifically states for Negative ground only. The car electricals are negative ground now. Any guidance on how to wire up the original clock?
I don't think it will make a difference. Everything on that car was 6 volt positive ground at one point, and the switch didn't hurt anything else right? Should be exactly like the rest of your gauges....
I would normally agree with you because I wasnt specific enough. All the other guages have been replaced with modern S/W imitations and are 12V neg ground. It doesnt matter to much of anything else but the clock's mechanism (motor) was designed to run one way I would think. I have been told that running the clock this way would affect the motor inside? I am no expert on this so thats why I put it on the forum.
I'm no expert either, and I don't know much about clock mechanisms, but I know that when I swapped my 49 to positive ground and 12 volt, the fuel gauge didn't mind (after I put the resistor inline). It didn't run backwards or anything like that, so in theory it should work just fine. I'm sure someone has a more definative answer
You converted to 12V but you stayed positive ground. Mine is 12V but changed to negative ground. I am gonna hook it up anyway and just see what happens. Maybe time will reverse and I'll just get younger everyday!
The original clock does not run on 12 V...it is a short-run-time mechanical mechanism that is rewound every several minutes by a sort of solenoid mechanism. Common design '40's-'60's. The clock runs only a few minutes on each wind, and as it runs down a set of points close. The points send electricity to the electrical puller that yanks a lever, rewinding the thing and separating the points... I suspect that it does not give a damn about polarity, and probably not voltage either, but give it a dropper anyway. Remember that traditional car clocks were not known for reliability, accuracy, or for even working after very short service.
Thanks a lot Bruce. I had the clock restored and it looks so good that I just have to try and make it look good. I imagine the lamp is also 6v so the dropper should make that work better/longer as well. I just got concerned when the Runtz paper said "Negative ground ONLY!"
I remember sitting in the car at night in dead silence and hearing the clock make a click as it wound the spring on the clock. I was probably waiting for sunrise parked at Hershey. It's weird at first.
Will one of those Runtz have enough current to run the solenoid? Aren't they just an LM7806 regulator in shrinkwrap? I'd expect a pretty good current spike with the following kickback when the solenoid fires. I have my '48 clock working on 6V but have it disconnected so I am of no actual help on this. (So what else is new?) Side note - apparently if you let the battery run down in the car eventually the solenoid can't pulse to open the points and they stay closed, burning the winding and breaking the clock. At least that's what I've read.
I suspect that electronic regulation would not be effective on a short flash use like this. I don't know, but I think I would use a resistor, which I believe would have some but not full rated effect on a flash 0n-off like this. My '48 has been through a million dead battery situations...clock has never worked worth **** (and that includes when delivered new to my Father), but if you put electricity to the winder thingy (solenoid is probably not a good name for it, it isn't as organized as that!) it kicks right off.
You guys are amazing with your knowledge. The clock has always been the last thing I ever thought about until I got one restored and wanted to try and use it. I guess I should just get it converted to quartz like everyone that I've talked to suggested. Just got hung up on trying to make it work after getting it rehabbed. It really looks like new now.
Just hookittothewire...12V isn't going to hurt anything in a split second! If it works, great, if not then worry about quartz.
If you are concerned about not having enough kick for the clock (using Runtz), then put a 1000uf @ 16v CAP across the clock terminal to ground. That should supply enough reserve for the clock surge. The Runtz reducers (if 7806 regulator) is only good for about .75 amps. I would check and see what the clock is fused at. My guess 3 Amps. Clock at that fuse rating is probably a good 2 amps when it fires. If this is the case, the cap I suggested might help.
Pretty sure the 3 amps is right...clock gets an inline fuse, since it would not be helped much by the Ford's breakers!
Go to the craft shop-buy a battery operated clock mechanism and adapt it to the back of your factory clock face with epoxy or what ever-clock will be more reliable than it was from the factory and no one will ever know but you
How about one of these with a heat sink? http://www.westfloridacomponents.com/T390PD/LM2599T-ADJ+3A+Step-Down+Voltage+Regulator.html
I may be missing something, but I think you're getting hung up on the term "ground". In any electrical system ch***is (as opposed to earth) ground is simply one half of the path the current needs to travel to make the circuit. If the clock originally grounded through the case on the positive ground system, simply isolate the case from the dash using a rubber gasket with sleeves or grommets for the mounting studs and hardware such that no part of the clock case will conduct to the dash and thus to the "new" negative ground. Then attach the power wire to the dash (the negative side of the circuit) and run a power wire (6 volts, doesn't matter how you get it) to the case. You could put a ring terminal over one of the mounting studs to do this. That should work. I'm not a double E, but spent a lot of time in electrical equipment manufacturing design and test. If anyone can spot an error, please let me know. -Glenn
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