The P.O. of my truck had a negative ground 12V installed, so I assumed the 6V --> 12V conversion had already been done.


Then realized the generator was still there, and the relays were all still 6V...
I guess the conversion wasn't done!


I haven't noticed any misfiring (as I'm sure the polarity of the coil was not switched appropriately), and I do seem to have windshield wipers that are not running off a vacuum line...


I was intending to go down the path of finishing the conversion, until I realized that a less expensive and more straightforward approach might be to just move back to the positive ground 6V.


I see the Optima red top is about $130...




Is there anything else I should check to make sure that going back to a positive ground 6V won't be a waste of $130?

 

They made 12v generators, and 6v generators can be converted to 12v. When you say the "relays" are still there, do you mean the voltage regulator? What is the system voltage at 1500 RPM? What battery is in it?

 

Thanks Ross.
There's a negative ground 12V battery in there right now. The regulator is still there, and by relay I meant the 6V flasher relay which is also still there.
(http://s7d9.scene7.com/is/image/GenuinePartsCompany/NWMDC?$Product=GenuinePartsCompany/1329263)

What's the best to measure voltage of the system at 1500 rpm?
Right from the generator with a multi-meter?

 

I believe across the ARM terminal at the regulator and any good ground. Is the regulator marked as 6v or 12v?

The simplest 12v conversion was to simply adjust the 6v regulator to a 12v setpoint. A 6v 35 amp generator will put out about 25 amps at 12v. Not super common but I've seen people do it.

 

Ha! I went out there to test, and realized that's not going to happen with the carb sitting on my bench awaiting a rebuild!

I think you're right Ross, I should be able to test generator output right at the regulator.

Assuming that comes back at 6 volts, I'm thinking more and more that I'll go the route of a new 6V battery instead of doing all the parts required by the conversion (alternator, solenoid, coil, ballast resistor, relays, etc.)

 

There is no advantage in reverting to 6 volt positive ground at this point unless you're a purist. You will have to change out all the light bulbs and flip the wire in the ammeter pick up, remove the voltage reducers for the instruments, turn signals, windshield wipers, and heater (if equipped). It sounds like all the hard work has already been done for you. Is your starter 6 or 12 volt? One wire alternators, solenoids, coil resistor, and relays are cheap - and you don't need a coil unless yours is bad or missing.

 

That's just the thing Bob, I don't think any of that work has actually been done.
I think the temp owner I bought this from - who drug it out of God knows where - put a 12V battery in because he didn't know any better. Not because any part of the conversion had been done.

The ammeter has been lit since I got it, the turn signals work, but I did put 12V bulbs in in most places - not knowing any better myself.

 

As an aside, most 6 volt relays function quite well on 12 volts for intermittent duty.

 

There should be nameplate tags on the generator, starter, and voltage regulator that will tell you what you have. If they have Ford part numbers so much the better.

 

Lit as in lighted? Did it show a charge when running?

 

The question in my mind is, if the gen and reg are 6v, and you have a 12v battery in it, will the reg tell the gen to do anything at all? I would expect the reg would see voltage above setpoint (even with a weak 12v battery), and tell the gen to just sit there. If you can get the engine started, idle it up to about 1500, and disconnect the battery. If it dies, the gen system is dead. If it keeps running, measure the voltages.

 

The regulator doesn't seem to have any markings at all.
The generator is 35 amp / 7 volt.

And I mispoke, it's just the battery charge light that's been on.

 

That sounds like a good test. We'll see what kind of power I can measure at the regulator, but I'd suspect the 7 volt / 35 amp tag on the gen is another indication that the 12V conversion was never actually done, and I could spend less time and money on a 6v battery than all the parts needed to do the conversion.

After driving a couple miles, I did notice some smoke from the generator wires, but other than that, the engine seemed to be running strong.

I could throw the carb right back on to test, I haven't disassembled it yet, but it was leaking - and it's proximity to the hot exhaust manifold made me nervous.

Thanks!

 

A generator and 6V relays doesn't mean the conversion hasn't happened. 6V relays are often preferable.

When you get your carb back on, crank it up and simply measure voltage at the battery with the engine above 1500rpm. If the generator has been converted to 12V, even with just a field coil change (which will get you 70-80% of the rated output), you should read over 13V. If you are reading less than 12V, odds are the generator hasn't been converted.

 

I would like to know how much run time you have on the truck. The more you post, the more, to me, it sounds like they might have stuck a 12 battery in it to show it as a running vehicle.
A 6 volt generator/regulator combo will not properly charge a 12 volt battery. It will always need more. That could be why you see the indicator.
How bright were the 12 volt bulbs you put in? Do you have any dash lights?
Most generator shops will test your unit for free, just take it to them. That will end all discussion about whether or not it has been converted without having to put it back together first.