Converting 6 volt to 12 volt, coil question.

[Lawson Cox]

You can always roll the car down a slight incline, switch on, in gear with the clutch in, then when it gets rolling pretty good, pop out the clutch and it will crank. That's what they did in the old days. It's a shame you cannot do that with an automatic transmission.

[G.M.]

I have 6 volts in all my old Fords with no problems. I did make 6 volt alternators out of the generators for the cars I drive which charges better and supplies more voltage at the lower RPMs and idle. The GM alternators converted to 6 volts POS ground work good as long as they have 24 stators so they charge at lower RPMs with a 3 1/2" pulley. I had 2 of the GMs but didn't like the looks of it in my Fords. 12 volts will have the same problem with a generator at low RPMs. With 6 volts you need good clean tight comnnections and 2/0 cables. I run a Garmin 12 volt GPS on all my 6 volt units with a cigar lighter extention with the polarity reversed to POS ground in the cord. With a generator every time the RPMs drop or the stop lights are hit the voltage drops too low and the GPS drops out, with the alternator it stays on even at idle. I have a 12 volt AM/FM radio in my 6 volt 39 P/U with a 6 to 12 volt converter made by a company in Florida I beleive it is Antique Auto Radio. It is about 2-1/2"s square and I have it in the glove box. I have used this unit for 15 years with no problems. Also the battery diconnects with the green knob are problems or will be a problem on 6 volts. These look like brass but are aluminum, brass plated and the small contact area that makes contact becomes oxidized and makes poor contact. I have had 3 of these go over the past few years. In the past month the one in my 39 was giving me problems. The starter sounded sluggish, the horn pulled the voltage way down and wasn't loud and the GPS dropped out every time I hit the brakes. I stopped for lunch and came out and the starter didn't work so I opened the hood and turned the green shut off knob a few times and it started. I developed a new battery shut off that will go on the battery terminal that will carry 175 amps constant with over 1000 amps intermitant which is a sealed unit with silver contacts. I put one on the 39 and now it acts like it is 12 volts.Bob Shewman [email protected] is thinking about putting a package together that will mount on the old Fords. Contact him if you have any interest. G.M.

[FlatheadTed]

If you wish to convert to 12 volt ,Yes you can use a Modern Ballasted resistor on your Cannister coil . The stock coil should be run through the stock ford resistor as well as the modern one .If you want to jump start your 6volt car when the battery is completely flat , connect the leads direct to earth such as a head bolt and one to the starter ,The starter one is momentarily connected to start .This needs a small wire from the hot side Eg the clip on the starter jump wire to the coil, run up the revs till its charging then unclipped the wire off the coil .hold the revs up till the battery is given a good charge ,

Originally Posted by 2002p51

I'm converting our '47 Mercury to 12 volt negative ground. Can I still use the original 6 volt coil with a ballast resistor, or do I need a new coil?

Can I use a generic canister type coil.