The Stovebolt Site Forums The Shop Area The Electrical Bay 6v or 12v problems

Okay I have a ’46 2 ton with a 216 the system aperies to be the original 6 volt but half the wires are cracking/corroding/just bad I need to replace them but the problem comes when I think about should I convert to 12v or leave it 6v? I know this is a much debated question. I’m leaning towards 12v for the following reasons:

I’m in Alaska 6v batteries are quite hard to find along with most 6v anything.

I’m in Alaska -Alaska is cold- I’m worried about my ability to get it running in sub-zero weather (Yes I would like to be able to run it in cold weather)

My gauges are already trash and I don’t have the lights so I can just start with 12v.

Also Alaska is dark, 6v lights are not known for their brightness I wouldn’t be concerned about this if we had a day and night through the fall/winter time but it’s always some stage of dark during these times and lights are necessary.

I would like to keep it 6v for the following reasons:

It’s original!

I can’t see keeping it 6v for just this reason is there anything else I should consider?

I plan on starting with regulators on the major parts because I can’t afford to purchase all new 12v components for a full conversion right away.

I’m very new to electrical and it’s my most dreaded part of this restoration any suggestions would be appreciated.

don't dread it, there's always lots of help on tap in this garage

I'd say you're best to go with 12V, not difficult at all if you get a proper repro harness, it's just plug and play [or maybe pray ] the only thing that would need adapting for 12V is a couple gauges, which you don't have anyway, so get it roadable first

Bill

Just a suggestion- - - -instead of getting several threads going, it's possible to ask several questions with one post and get all of them anwered. With the very simple wiring system on your truck, converting to 12 volts is ridiculously easy. The 6V starter will work fine on 12 volts with no modification. Just swap the light bulbs to 12V, install a 12V ignition coil and a ballast resistor in the ignition system (same distributor, points, and condenser), and either use a 12V generator and regulator, or install an internal-regulated alternator and forget about the old regulator. Just bolt the Armature and Battery wires together on one regulator terminal, or just bolt them together, tape the connection, and remove the regulator altogether.

The 6V wire harness is plenty heavy to carry the 12 volt circuits, much heavier than necessary, in fact. Until you're ready to do a full rewire job, just tape up the bare spots and press on!
Jerry

akguy, What are you doing where it is so COLD????? Back to the point, It's great to keep it original, but if you want to drive it and not show it, go with 12 volts. You have already listed several reasons why, like parts availability, safe lighting, and ease of service. As Hotrod said, it's simple to convert. Good luck!

akguy:
I'd say go for the 12 volt conversion. There's an article about such conversion in the Tech Tips section.
Good luck.
Charlie.

For all the reasons you have stated 12V is the better option especially since you say the gages are trash.

I will take exception to the common belief that a 6 VDC motor is just fine on 12VDC. After all the effort why stay with what is wrong and just do the job rignt?
Yes it will run BUT for how long?

I would for sure carry a spare starter if you go a long ways from town in freezing weather.
JUSTIFICATION for my argument
current is proportional to torque.
speed is proportional to voltage
Horsepower is proportional to speed

the torque demand of cranking does not change. You do speed the motor up -- by near doubling crank speed so it should start easier which is the reason it is favored. I have done it too especially with balky engines or new and tight OR if all I had was 12V.

What may be saving you is the counter EMF being higher at the higher speed thus reducing current.

For your other question on whether it is 6 or 12 now. Count the cells in the battery (3 for 6V and 6 for 12V) or measure volt across battery terminals.
Dan Bentler

A 6 volt starter motor will last longer on 12 volts then it will on 6. There is very little difference in them.
I vote for the 12 volts & an alternator. There is a lot of darkness up there, You will be useing lights most of the time. At slow speeds you will still maintain the bat.

First all... cold is your problem. Starting a truck with a cold battery, 6V or 12V it doesn't matter, is tough. Batteries lose their charge in the cold. I'd consider moving the battery from under the cab into the engine bay, or a warmer place in the truck.

Second, your wires are more a problem than the equipment. If your wires are creating a short ("cracked/corroded/just bad"), it doesn't matter which starter, alternator, generator, etc. you have. You won't have power. Make sure you have the proper gauge wires for a 6V system. 6 volt systems require more current, which requires a heavier gauge wire. Get a wiring diagram and check the connections and gauges of each wire.

Those things are rather independant from the 6V/12V issue. But my vote also goes for the 12V & alternator setup. It seems to fit your needs, and you should be able to find everything in Fairbanks.

Just did a 12 volt conversion on mine, was well worth it. I to wanted to keep it as original as possible, but with the easier starting and maintaining of the 12 volt system and avl. of accessories, It was the right choice for me.

Well I am just an industrial motor control electrician so what do I know? ONLY that equipment operated at design parameters lasts a long time.

Take a drill motor and connect it across 240 and see how well it does. Drill motors are basically a series motor - near same as starter motor.

I find it interesting that there are so many posts on starter problems.


Dan Bentler

Most likely, there are many posts on (6v) starter problems because most old trucks have wrong gauge battery/ground cables. Add to that the higher probability that the 6v starter motor is older and more worn out than 12v starter motors.

Regarding a 6v starter having a shorter life when run with 12v, that is hard fact to argue against. Except that the amount of time needed to start a well-tuned truck with a 12v electrical system and a 6v starter should only be a few seconds of operation for each start.

There have been many 6V starters run on 12V for years.

It is not as simple as just swapping the starter. The flywheel must be changed too. That is a good reason to keep a 6V starter.

Dan, you're obviously not particularly familiar with the construction and maintenance of an automotive starter. There are at least three methods of winding a starter, and the General Motors 6-volt starters are usually wound with three field coils in series, and one shunt coil to control the speed at a reasonable level. "High-Torque" 12 volt starters actually use a 6 volt armature, so there's a lot of interchangeability between systems. "Super-Torque" 12 volt starters that we used to install on the race cars are actually built with all 6 volt parts, armature and field coils. A starter is designed to run at a massive overload for a few seconds, then have a long cool-down period. The GM factory standard operating conditions call for a maximum cranking time of 30 seconds, followed by a 20-minute cool down. Try disabling an ignition system and actually running a starter for 30 seconds. It feels like forever. If an engine doesn't start in the first 5 to 10 seconds of cranking, something is drastically wrong.

6 volt starters will last for many years on 12 volts, as long as the engine is kept in a reasonably good state of tune. The "stomp start" stovebolt engine starters with the manual engagement of the pinion gear and a simple mechanical on/off switch will outlast a solenoid-engaged starter by a factor of 3 or 4 to 1.
Jerry

Okay before this gets out of hand I'm finishing the starter debate with a simple equation (me + 2 6v starters + no money for a 12v starter = sticking with the 6v starter with 1 extra replacement for oh crap situations)

Can anyone explain the 12v internal parts for the 6v generator for converting the excising 6v to a 12v while still using the housing?

Has anyone done it?
Is it something the amateur mechanic can do?
Or should I just buy a 12v generator to start with and jerry rig a bracket?

not something for an amateur, you should find a 12V generator and bolt it on, it'll be almost identical to the 6V, no need to camouflage it

Bill

OK, this topic is moving into a new area that also has the potential to get a variety of opinions.

12v generators can be easily found and a bracket should be easy to find with a used generator. You should also get a matching voltage regulator.

If you want the simplest, most reliable, and best-performance (non 6-volt) charging system (at all RPM), consider an alternator. The simplest alternator to install would be a one-wire alternator. You will need mounting bracket(s) and if you want to buy it/them (this bracket set might work on your 216).

You may use your existing generator wiring. Maybe someone with first-hand experience will post information about how to hook this up to you ammeter/voltmeter (what was used-in or is available for a 1946 truck).

The 12 volt generator will be slightly longer than the 6V, requiring a different mounting bracket or a spacer to take up the difference in length. Nobody but a concours car show judge would be able to tell the difference in appearance. I agree that the alternator would be a much better choice.
Jerry

So what’s the difference advantages/disadvantages of a generator or alternator

An alternator can be spun much faster than a generator because of its internal construction. With a small diameter pulley, that means the alternator can produce enough current to keep the battery charged at idle. A generator must be revved up above idle to produce enough current to keep up with the demand of things like headlights, heater blower, electric wipers, and other drains such as stupid-high wattage sound systems, etc. The alternator can handle all those loads, and still have some amperage left over to charge the battery.
Jerry

So would I just buy an alternator and drop it in or is there something I need to add in the electrical system?

About how much do 12v generators/ alternators cost?

An alternator mounting bracket kit that might work on your engine is in a post above.

Here are some sources on one-wire alternators and a one-wire alternator wiring diagram.

If you are converting to 12v, here is the 12v conversion Tech Tip if you have not already seen it.

Sort of on topic for you. Are you sticking a block heater in your truck? Also, sticking a magnetic heater on the oil pan is nice, to warm up the oil. Even with multigrade modern oil, it's amazing how much more drag there is on the starter, even at freezing, let alone at colder temperatures.

For you warm climate types, magnetic heaters are whacha stick on the ski-doo to fire it up, or the snow blower.

If you are in Alaska though, I'll betcha you know this!

Yes I plan on installing at least a pan heater it’s kind of critical for any cold weather starting up here.