12-volt conversion & negative ground

[Kaiser Ranchero]

We have a '53 Kaiser Manhattan 2-door which is currently 6-volt, positive ground and needs a new battery.  We were wondering what needs to be done to convert it to 12-volt, negative ground?

[joefrazer]

To convert to 12 volt:
1. Reverse the polarity on the battery connections so that the car is now negative ground
2. Install a 12V ignition coil. Reverse the polarity on it too (switch the wires)
3. Replace all bulbs with their 12V equivalents. Do the same for the cigar lighters.
4. Replace the 6V generator with a 12V unit. Or, replace the 6V generator with a 1-wire 12V GM alternator.
4a. If you use the alternator, remove the voltage regulator and run the battery connection from it to the alternator. The Field and Armature wires to the voltage regulator can be removed from the car.
5. You will need to add voltage reducers to step the 12V down to 6V for the instruments. Don't forget the radio, unless you plan to replace with a modern unit.
6. Leave the horns as they are. They'll be alot louder, but still work.
7. Most folks leave the starter in place. It'll spin alot faster but unless there is prolonged use (lots of cranking at a single start), you won't burn it up.
8. Inspect and replace any questionable wiring. While the amperage required to get 12V thru the system is less, the voltage is now twice as much. So, the chances of melted wiring is greater.
9. If the car has a standard transmission, the overdrive components might need attention. I'm not certain of that...maybe another reader can answer that one.

Most folks want to swap when the car's starting becomes sluggish. In most cases, it can be traced to poor connections. Because there's only 6V, you need clean and tight connections for the car to start and run properly. A correctly set up ignition system with 6V should work as well as any concurrent 12V system.

Hope this helps!

[Fid]

Regarding the overdrive components, we once converted a Henry J to twelve volts and left the starter (It was a Delco starter, the Autolite starters are not so forgiving) and overdrive components in place and drove it for 9 or 10 years with no problems. Just a personal note, I leave all my cars 6 volt now and I never have any problems. I hear the complaints about sluggish starting too but that is almost always corrected by installing the proper gauge battery cables.  These cars being 50+ years old now have not survived without maintainence, upgrades or repairs.  The battery cables corrode  and many were replaced years ago with 12 volt type which are 2 gauge. The originals were 1 gauge and using a 2 gauge wire for a battery cable makes a big difference. Of course if you want a modern stereo or CB radio you need 12 volts.  The six volt systems used more current (amps) so if the original wiring is not frayed or visibly corroded, it will serve just fine.  As I mentioned, the Delco-Remy starter in Henry J worked fine on 12 volts but I once tried to jump start my '48 Frazer, which was Autolite, using a 12 volt battery and it tore one of the components apart inside it so I don't know if the Autolite starters, which operate a little differently, would work on 12 volts. If joefrazer has done it, I'd say it'll be fine.

[superk226]

You did not say what the reason for converting to 12 volts was other than you were in need of a new battery. Assuming that your primary interest is in installing new gadgets that operate on a 12 volt negative ground system, I would convert the existing 6 volt positive ground system to 6 volt negative ground system and purchase a power converter to raise the voltage from 6 volts to 12 volts for the new gadgets. Fid's suggestion for installing the proper size cables and making sure all connections are good is must for the six volt system to work properly. My cars are still six volts and they work just fine.

[ken taplin]

I have converted several of my 6V cars to 8V. I don't do anything but tweak the voltage reg. to 9.2V and unhook the radio if there is one. Everything works much better. Elec. guages tend to be optomistic but work.

[mow4alivn]

How about the clock and the heater blower motor can they handle the 12 volts?

[superk226]

Twelve volts on the clock and heater blower motor would eventually burn them up.

[ken taplin]

My cars didn't have clocks. One heater had a two speed switch and seems to work fine on the low speed. The other ones I have put those old time rehostate type switches in the line.

[ben-tex]

We found a replacement 12 v fan motor for the heater at NAPA when we converted a 54 to 12 volts back years ago. s