12 volt or 6 volt

[Pooshoe]

I’m  thinking about 12 volting my car. It’s all stock, just kinda hard to start in the morning and when it’s cold. I have the hei distributor but I do like the six volt systems and The car has ran with the 6 volt system for year with no problem . the wiring harness is not in bad shape for the age so I’m not worried about that, going to 12 volt I will pull less amps. Should I try to change the fields in my generator, get a last model 12 volt generator or go to and alternator?  I know I have a few other things to change also but I’m torn to keep it stock or do the upgrade.

[maddmaxx1949]

I would make sure you have extra thick battery cables if you haven't done that yet. Helps cranking on 6v a ton.  I have seen people use 8v to get a little more oomph during cranking but that is known to be hard on lights and electronics. I am a little biased towards 6v just because I like the stock configuration and I'm not entirely sure what the 12v conversion constitutes of. 

[Sniper]

I converted my 51 to 12v last year.  Battery, alternator, regulator and bulbs where all I had to change.  I emulated the charging system of an 87 Diplomat in my case. 

 

http://www.yourolddad.com/12-volt-conversion

 

Napa was able to give me 12v versions of my 6v bulbs, just took them in and they set me up. 

 

I did put in a 12v heater blower motor mostly because my original 6v one was not useable.

 

http://www.yourolddad.com/blower-motor

 

Wipers were a whole 'nother deal and I ended up fabbing up a current limiting circuit to slow them down, not 100% satisfied with it though, seems to be too slow for a one speed setup.  The speed I have would be perfect for a slow speed setting on a two speed setup.  Still mulling over what to do here.

 

 

[Pooshoe]

24 minutes ago, Sniper said:

I converted my 51 to 12v last year.  Battery, alternator, regulator and bulbs where all I had to change.  I emulated the charging system of an 87 Diplomat in my case. 

 

http://www.yourolddad.com/12-volt-conversion

 

Napa was able to give me 12v versions of my 6v bulbs, just took them in and they set me up. 

 

I did put in a 12v heater blower motor mostly because my original 6v one was not useable.

 

http://www.yourolddad.com/blower-motor

 

Wipers were a whole 'nother deal and I ended up fabbing up a current limiting circuit to slow them down, not 100% satisfied with it though, seems to be too slow for a one speed setup.  The speed I have would be perfect for a slow speed setting on a two speed setup.  Still mulling over what to do here.

 

 

What size pulley did you have for the alternator?

[garbagestate 44]

I changed my 47 to a 12v to start but everything else is still 6v positive ground. It required 2 batteries. I had to do it that way because I have a fluid drive coupled to an m5 transmission and I didn't know what 12v would do to those expensive and hard to find solenoids and other stuff. Rube Goldberg would've been proud. I don't know if I'm going to keep it that way but it makes the it easier to start until I can get it on the road and run the motor in a little bit. Also, I used a 56 Dodge starter that is 12v but has a gear that is compatible with the tooth count on the flywheel. (144 teeth or something like that) The next year they upped the tooth count to 177 so a later starter won't work. Some have suggested that although the 6v started works fine on 12v, binding and failure to disengage can happen. Anyway, good luck

[Merle Coggins]

I remember working on some Link Belt excavators 'back in the day' that had a 12/24 volt system All of the electrical system was 12 volt, with a 12 volt alternator, but the starter was 24 volt. It had 2 - 12 volt batteries with a fancy series-parallel relay/switch in between them. It would connect the batteries in parallel under normal conditions for 12 volts, but when you pressed the start switch it would switch to series connection to give 24 volt to the starter motor. It worked well, but it was weird to work on.  

[Sniper]

10 hours ago, Pooshoe said:

What size pulley did you have for the alternator?

Whatever it came with, just bought a 78A alternator for an 87 Diplomat.  I also had to add a ballast resistor to the feed for the coil and I updated to a newer coil as well.

[Sam Buchanan]

Here is the 6v system in my '48 P-15. It spins as well as any older 12v vehicle I've had and has never failed to start. The key components are fresh, properly-sized battery, starter and ground cables, and the 6v alternator which keeps the battery hot all the time. 

 

 

Here is the vendor where I sourced the alternator:

 

https://www.ebay.com/str/HowardEnt?_trksid=p2047675.l2563

 

It is internally regulated so one wire is all that needs to be connected, the old regulator gets tossed.

 

Battery cables:

 

https://www.batterycablesusa.com/1-0-gauge-battery-cables-0-awg.html

 

Provided the starter and ignition is in good shape there is no reason why a 6v system shouldn't start your car reliably.

[DJK]

I went with the Bill Howard 6v pos ground alternator, very happy with it. 

[Booger]

Listen to Sam and DJK (and the rest of the pureists, to which I am one)

the conversion will keep you constantatly chasing problems

I like the 6v alternator

you got bigger fish to fry

[keithb7]

There are good arguments either way. 6V or 12V. Whatever works for you go for it.

My personal experience is that I like to keep them 6V. When properly maintained, 6V works well for me. I have zero complaints. I own two 6V positive ground Mopars. I have no reason at this time, and no future plans to convert to 12V.

 

Same could be said by someone who prefers 12V.  What you choose to do with your car, is nobody's business really. I heard a great saying recently about working on old cars...."Doesn't matter how it's done as long as you have fun."  So true. 

 

I also get a kick out of the younger crowd who come chat about my old Mopar car. "6V positive ground" I declare. They sorta go "Huh?" Or "Wow. Really?"  Yep really...And a carburetor! 

Edited December 18, 2020 by keithb7

[Sniper]

If a 12v conversion has you constantly chasing problems the issue isn't 12v vs 6v but rather the mechanic that did the conversion.  Converted mine last September, zero issues to date. 

 

Now if you want to keep it 6v have at, it's your car.  If you want to convert to 12v, have at it, it's your car.  But let us at least be honest in our comments here.

 

My thinking on keeping it 6v positive ground is that is fine if you are planning to keep it near original.  If you want anything in the way of modern conveniences, like AC or a radio that doesn't have vacuum tubes in it then going 12v makes that so much easier.    Some guys put in a hybrid 12v/6v setup to run some modern stuff and my thinking there is why?  Just convert completely or do without the 12v stuff.

[JBNeal]

I cringe when I see these old cloth covered wiring harnesses as they are hiding a nasty little problem:  impedance due to oxidation.  This could be a ticking time bomb on an original buggy...

 

additional information - minor starter upgrade

[Jeff Balazs]

FWIW you can pretty much have everything you need with a 6v system. Putting a 6V single wire alternator in makes it very reliable. I am in my 6th year of using my 52 B-3-C daily and it has not let me down yet. I am running a full time electric fuel pump and have a very decent stereo system. It works just fine.

Jeff

[RobertKB]

I don't see the point of changing to 12V if your 6V system is working well. I don't even see the point if the wiring did need replacing.

 

Making sure you have the thick battery cables for a 6V system is important for starting as is having clean terminals throughout. A known good starter or a rebuilt one is also a plus. I have three old Mopars and sold a fourth one and all start and run well with the 6V system. 

 

No need to make work for yourself if not really necessary. Just my "two nickels worth" as we got rid of cents years ago in Canada.

Edited December 18, 2020 by RobertKB

[laynrubber]

I converted and it was no real hassle. Reason was.... we do long distance trips with it and it’s just easier to find parts on the road. Last time out I needed a 6 volt flasher....found it but it took some digging. Another time was a headlight. What ever your reason to convert it was no real trouble. I went with a 60s Ford style alternator because I have several other Fords PLUS I wanted to run an electric radiator fan.....an alternator gives more consistent charging while sitting at idle, where I needed better voltage to run the fan. 6 volt is fine, we all have our reason to have converted. I don’t regret bringing it up to 12 V