12 volt tech needed

I know this has been discussed at length on here before and is common knowledge to most but I need help. I could only find some of the info needed when I did a search.

I recently had my starter rebuilt on my '49 Ford with the flat-6. When this was done I had the shop convert it to 12 volts with the obvious intent on changing the car over to 12 as well. I'm just kinda unsure what needs to be done from here. I'm very new to the electrical stuff.

If I'm on the right path I believe I need to get a 12 volt coil, condenser and solenoid. I'm gonna have to keep the points for now. Also a GM alternator (will one from a '79 Monte Carlo work?) to get rid of the generator and regulator, 12 volt battery and bulbs/headlights. My heater fan will be a new 12 volt unit so no voltage reducer needed I guess(no clock or stock radio either). I'm also putting in a new poly gas tank so my sending unit will be 12 volt as well.(know of a cheap one?)

What do I do about the positive ground? Do I just install the new battery with a negative ground and be done? Do I need to reverse polarity on all my wires? What else needs to be done? I don't want to upgrade to an electronic ignition at this time so I just need the basic low-buck info on getting this thing rolling again on 12 volts. I know there are books on this stuff but I really don't have the time to wait the week for one to get here.

I sold my '65 and this is now my daily driver. Need to get the 49 back to running fast or I'll have to post my coordinates for a food supply drop. Currently running low on Captain Crunch.

 

Yes, install the new battery with neg ground. The Monte alt is a good choice. JC Whitney has new sending units for the tank. They even have a "set" with matched sender and gauge. What gauges are you using? The stock ones will have to have a voltage drop to work with 12 volts. A voltage drop is the easiest way. The new coil would have to be wired with a ballast resister to run with 12volts. I think you have to install the coil wired in reverse from the old 6 volt pos ground system. Buy Tex Smith's book on wiring a car (written by Skip R.)

 

I just converted my '49 ford 6cyl to 12v. It was easy. I still am using the 6v starter and have had no problems.

You will need a 12v stater sol from like a '60's ford car or truck. The usually have 2 small terminals on them. You will also need the 12v light bulbs. you can use a reducer to convert the fuel, oil press., and water temp guages. The ammeter needs no converting. To convert from positive ground.. you need to make sure everything get's converted. I stuck in a 12v battery and went from there. pos cable goes to the start sol, neg cable to the block. I redid all my wiring, so I don't really know how much of it would have worked if I just switched polarity. I'm sure the starter solenoid will have to be rewired. You can use a chrysler single groove pulley alt. It will fit on the same bracket gen did with just a longer bolt and some spacers. The double groove pulley type will not clear the fan. I can't remember all the details right now, but if you have a specific question just PM me I'll try to help you out best I can.

 

you don't need a 12 volt coil. Just put a ballast resistor in series with the ignition switch lead.

BTW, swap the polarity on the coil, too. With a 12 volt negative ground system, the minus side of the coil should be connected to the distributor.

 

I think I understand what you need to know.
First off, wiring is NOT polarized, motors are, wiring is not.
ANY large case GM alternator with an internal regulator will prove very reliable. Grab the cheapest one at NAPA if you're not going hog-wild with the electrical bits.
Coils are always grounded through the distributor: if the battery has a negative ground, the (-) post on the coil goes to the distributor. 6 volt coils require a ballast resistor wired into the feed side.
Blower motors can use a ballast resistor (the same as a seventies Mopar ignition resistor) and no need to change the blower motor.
Starters are not polarity sensitive, they will only turn one way, regardless of battery polarity (no, I do not really know why).
Dash lights, when equipped with a dimmer, need not be changed from 6 volt, just turn the dimmer way down. This also helps with guage illumination, as you can turn them UP!!
6 Volt spec'ed wiring will be very adequate, as the need for guage sizing goes down when volts go up.
Ammeters are not voltage sensitive, they only sense current, and will work in your house, if you wish.
I've had some cars whose guages were all not voltage sensitive (50 Olds, 51 Chevy), hooked 'em up to 12 and they worked fine.
6 volt clocks will work great (actually better!!) on 12 volts.
Hope this all helps,
Cosmo

 

Very very good information from all! Keep it coming! I'm going to attempt to soak all the info I get in before I ask more questions. I've gotta kinda round stuff up and lay it out to get my brain around it. I thank you all for taking the time to answer my questions.

 

You dont need to use a 12 volt starter if you are running a flathead, this has been proven over the years.
And you dont need to swap the solenoid either.

Im pretty sure its the same with all types of starters to. The reason for this is the they are not built to run continous just crank out a lot of torque, even at the original voltage.

What happens when going from 6 to 12 volt is that he currént going though it will be doubled and creating more heat, and power of course.
And its the internal heat that can kill the motor. But since you only run it for some seconds the heat will never build up to overload/damage level.

Regarding ameter's they are not voltage sensitive, but the are polarity sensitive, so you need to swap the leads on it to get it to show charge and discharge right after the polarity change.

 

The starter had to be rebuilt so while it was down I had the shop go ahead and convert it over to 12 volts. I know it would have worked at 6 but it hits really hard and I didn't want to worry about replacing the spring on the drive after a few hundred miles.

I planned on changing it over to 12 without any rush but when I sold the 65 out of the blue, I was left with a 12 volt starter and a 6 volt car. That's why I need to get it done fast.

 

bttt, Anybody else with info?