The Stovebolt Site Forums The Shop Area The Electrical Bay 12V or not to 12V: That is the question

I'm new to the board having recently aquired a '46 'Big Bolt' 2 Ton and have been making a mental list of the things i'd like to do to the truck.

Naturally since my truck has been sitting for quite awhile, I figured plugs, wires, cap, rotor would be obvious things to replace, but then I got to thinking about the generator and coil, and it occoured to me that maybe I outta have the 6V generators field coils changed to 12V while I was doing the rebuild, and replace the regulator with a 12V and the coil.. pretty much a 12V conversion.

So I mentioned this to a friend of mine, and he thinks it's a bad idea to go to 12V. Here's what he says:

So whats the opinion of the Stovebolters here? Am I going to do more damage than good converting to 12V? What are the pros and cons of both?

This has been discussed many times before. If
you use the search and type in "conversion", you
will get a lot of feedback. Personally, I don't
see a need for it unless you plan to install a
lot of electronic extras. Cecil........

There is nothing wrong with a 6 volt system. The main rule is "good grounds". The second rule is "big battery cables". Many people make the mistake of replacing the cables with the 12 volt ones from the FLAPS. (That's the Friendly Local Auto Parts Store) They won't carry the current you need for your 6 V system.
As to the theory about a 12 volt spark- Most 12 volt systems use a ballast resister in the ignition circuit to reduce the voltage to the coil. I thought it was to keep the points from burning up. This is the first I've heard of the theory about "...........and will affect piston and cylinder life, and head and valve life."
Congratulations on your new truck. If it were mine I'd keep it 6 volt.

I m staying with a 6V...it all works...and if it works...don't mess with it...I'll spend my money on some other parts for now.

6v voltage to plugs 30,006 volts
12v voltage to plugs 30,012 volts

Most point systems reduce voltage to the points to around 7-9 volts while running. I don't think it will hurt the engine. But with big cables 6 volt is fine. Brian

See I learned something new today. The 6 volt systems produce and ignitions spark that is "kinder and gentler " then the 12 volt counter parts!

Properly wired, the 12 volt system will provide the same voltage to the plugs as a 6 volt system. You just need to get the correct coil and resistor. As far as destroying the engine with hotter spark and the 216 not able to handle it, he's blowing smoke. The 235 block and head were cast from the same metal as the 216 and have been running on 12 volts systems for a long time.

I have no problems with a 6 volt system until it gets cold out. And seeing you're from western Nebraska, I know it can get cold out there. If you run a 12 volt system with a 6 volt starter, your engine will turn over a whole lot faster, needed when it's cold. I've spent some time in the sandhills and have witnessed the effects of -25F temps with strong winds. Bad enough that we would not only plug in a block heater, but wrap a tarp around the tractor engine to keep the wind from sucking out all of the heat. Even with that many times we only had one tractor that would start reliably, a F-20 with a hand crank.

I put a 12 volt 10SI alternator on my 52 four years ale, and have never looked back.

I agree with all of the above. 12 volts wont hurt your engine and it will help when it is really cold but 6 volts will work bettet than a lot of people think. I converted my old tractor to 12 volts but it still was'nt great about starting.I have left my 54 gmc one ton 6 volts just because I didn'nt want to fool with changing everything.e.g. lights, gauges,etc. If you do the change you can get by with out changing the starter.It will work a long time on 12 volts. Just dont crank it till it gets hot.As above the cables on 6 volts need to be the big ones and the grounds need to be really good. Battery to engine, engine to frame,frame to body etc.

if you have a 6 volt system you will be messin with it to keep it mantained so it will start good they are fine but im spending the time and money on my riggs to go with 12 volt as iv had 6 volt in the past and dont want to go there any more ra ra ra ra vrooommmm " lets push it

The information in your quote is nonsense. Some people like 12 V better and some don't. The problem areas are in the gauges and heater blower, etc. If you sort them out you will have a good 12V system. Oh, and there seems to be an overwhelming opinion that 6 V starters work fine on 12 V. However, it is also often stated not to turn it over too long at one time on 12V.!!

Do any of you go the 8-volt route? Enough extra juice to spin the starter, nit so much that you cause problems.

I had an 8v battery in my truck for a while and it was nothing but a pain. Keep blowing light bulbs and couldn;t get my generator to charge correctly. Put in a 6v Optima battery and 00 battery cables, all my problems are gone. It spins my starter as well, if not better than the 8v.

Just joined and read a ton of interesting info I probably wouldn't have seen elsewhere. I just got a 1950 Chev 3600 and have pretty much decided to convert from 6v to 12v. My question is: Should I include a rewire harness job at the same time for safety / reliability sake? The tail light/brake light & rear turn signals work fine but the instrument (dash) lights and head lights only work when they feel like it! I'd also like to add some decent additonal taillights. Some of the articles I've read talk about just going to a 12v generator instead of an alternator.
This is my first "oldie" and could use some advice. Thanks.

Some people like the 12V generator because it looks like the original. As far as your wiring harness is concerned, the 12V will actually use less current. A good 6 volt harness will work just fine. However, I would be tracking down the problems that you mentioned before modifying anything.

Thanks for the input. Now it seems that the floor button low/high beam dimmer is involved. I got the headlights to go on, but when I hit the dimmer, they went out.

Mine does the same thing, I just keep hittin it till it comes back on. Probably bad ground, bad dimmer switch??????

Well the '46 has come a long way since I first asked the question.. I was pretty much fishing around to figure out what to put on my "to do" list.

In my experiences so far, I have to say that I really don't have a problem with the 6V system, so long as you've got a good solid FAT ground. 12V systems are far more forgiving to weaker grounds.

Every day I get something new running on this truck, i'm more and more convinced I outta put her back together as close to she was when she was new.. so I guess i'm going to stick with the 6V system, since the biggest argument for going to 12V seems to be faster cranking when it's reall cold out.

Hey, if it's -25 outside.. you won't catch me toolin' around in that truck!

Good choice, I just finished, (well sort of) my 46 1.5 Ton, kept it mostly original, but I love being somewhere and telling them it is stock with a 6 volt system. It was worth it, just for that look I get from them. You know, that 'calf at a new gate' look. 6 volt?

One other thing you will have to think about .How safe is your 6 volt lights at nite? I know i changed my 48 over to 12 volts and am not a public danger at nite anymore. Before that i was hard to see and my headlites were not as bright. I also like to have a radio. You can not tell my truck has been changed over as it runs a generator off a 56 chevy and the batt is hidden. Dont waste money on 8 volt batts . The next thing is 6 volt batt are more expensive,not found on a sunday. Not worth the torment . Its easy safe and a cheap way to have a very nice running and STARTING truck. Mine cost me about 150 dollars with batt , light bulbs,one voltage drop for fuel gauge and heater motor. My next plus is i will be changing to electric wipers that no one will even know it has.
Lots of +s for 12 volt not many for 6 volt except you can just jump start it now and than.
Next time your sitting there with a hot motor at the gas pumps and everbody is looking at you and it wont start you just may change your mind.I know i did after wasting moneys on batts, cables starter rebuilds. The biggest plus is it runs so much nicer,maybe its just me.If you drive it 12 volts is the only way to go.
Oh and Hello nice place, thanks for a great place to learn.

I've never had a problem with 6v light brightness, using 6v bulbs. That said, I prefer to convert to 12v for most things.

I had the same problem with the dimmer switch, ChevyShelly and First 50, just replace the switch--works fine.