6 volt or 12

frank-k

Active Member
I pulled the engine yesterday and decided I am going to clean things up while it's out. I am going to install a new wiring harness and I am looking for opinions on keeping the 6 volt system or upgrading to 12.
The purist in me says keep the 6, but the practical side thinks I may be better off with a 12 volt system (along with encouragement from coworkers). Can anyone chime in with the pros and cons?
This also may be the wrong forum for this post. If so, please let me know.
 

Pat n Pat

Active Member
Hi Frank-k:

If you are rewiring the car, wire it for 6 volts. six volt wiring is larger than 12 volt wiring as it has to carry twice as many amps to provide the same amount of energy. Six volt wiring is more than ample to carry 12 volts.

Given that, you could run 12 volts with no problem and convert back in the future should you decide to go "purist". You would need to replace all light bulbs and your turn indicator "flasher". Your starter will work very well on 12 volts (and spin fast). We have run 12 volts through our 6 volt starter on our '31 Buick Track Racer for over 5 years on the Great Race. Never a problem. You may need to replace your solenoid. I am not sure how yours is set up.

You will also need to have your generator to 12 volts. Keep the replaced parts if you decide to go back to 6 volts (or better, convert to an alternator).

Pat n' Pat
 

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LONG

Active Member
converted my stock wiring to 12V. installed a gm 10si and I have a pertronix 12v dizzy. nice to be able to charge cell phones/ GPS/ have a radio.... and find parts. all depend on how you want to experience driving a 60+ year old car. easy convert.
 
Or I could supply you with a 12volt "Mini" starter that's a direct bolt-in.
While you are upgrading go for the alternator.
 

frank-k

Active Member
Finally back on my project...I purchased a generic wiring harness from Kwikwire. Before I ordered it...a little over a year ago, I inquired to make sure it would work in a 6V application. I was told yes and have had that reconfirmed recently. I have been reading through the instructions and looking at the original wiring diagram in the Buick repair manual. I am trying to make sure the generic kit is going to work without a lot of extra effort.
The original had 5 circuits and the new one is 14. Some of the wire sizes are the same as the old, but a few are smaller. For example, the dome light circuit is 30A fuse 14 Ga wire, and the new kit is 25A fuse 16Ga wire. I can change that fairly easily, but do not want to rewire a substantial part of the harness.
I chose the generic for budget reasons. $250 as opposed to $1500+- for a direct replacement. I am not restoring the car. I am only working on the mechanical functions to make it safe, reliable and fun to drive. I didn't have 30-40K to invest in a car that when finished would only be worth 15-20K.
I am a novice, so any expert advice is appreciated. What are your thoughts?
 
Buick had standardized on a 30 amp dome light circuit in all cars a few years prior to 1953. The capacity was beefed up to handle the rear seat cigar lighter used in the 4-dr senior series cars.

A look at the wiring diagram for the '48-49 Special shows 16 ga wiring was used in the dome light circuit. The wiring diagram for the '49-50 Pontiac (no rear lighter either) shows a 14 amp fuse in the dome light circuit. So the 16 ga wire in the new harness should be fine for your car.

The extra circuits in the new harness could be used to power some loads if other fuse/wire sizes appear under-rated. By examining the loads on the other circuits, we could determine suitability of the new fuse/wiring.
 

frank-k

Active Member
Buick had standardized on a 30 amp dome light circuit in all cars a few years prior to 1953. The capacity was beefed up to handle the rear seat cigar lighter used in the 4-dr senior series cars.

A look at the wiring diagram for the '48-49 Special shows 16 ga wiring was used in the dome light circuit. The wiring diagram for the '49-50 Pontiac (no rear lighter either) shows a 14 amp fuse in the dome light circuit. So the 16 ga wire in the new harness should be fine for your car.

The extra circuits in the new harness could be used to power some loads if other fuse/wire sizes appear under-rated. By examining the loads on the other circuits, we could determine suitability of the new fuse/wiring.
Thanks Todd,
I am on the fence on what to do. I have been cross referencing the Buick wiring diagram with the specs from the new harness. about 40-50% are one size smaller on the new harness. I wasn't sure if the existing wire was larger because of the load on it, or it was sized because the fuse feeding it was larger so it could supply multiple circuits.
I figured I could change a couple of wires if they were undersized, but I did not want to start replacing a lot of wires in the harness. Kwik wire said I can return the harness, but if it will work, I would prefer to keep it. I did see that Ron Francis Wiring makes a 6V universal harness. I don't know if that would be a better option.
If I was doing a restoration on the car I would opt for a direct fit harness. Unfortunately I can't afford to go that route. I have considered attempting to build the harness myself by using the old harness as a pattern. resourcing all the correct wire and connectors made me shy away from that. Along with it may slow things up even more. I'm not sure how long it would take me to duplicate it. I would also have to correct any splices made in the old harness over the years.
I would like to hear from folks that have used the universal fit harnesses and get their opinions as well. I am definitely a novice when it comes to rewiring an entire car.
 

HighOctane

Member
converted my stock wiring to 12V. installed a gm 10si and I have a pertronix 12v dizzy. nice to be able to charge cell phones/ GPS/ have a radio.... and find parts. all depend on how you want to experience driving a 60+ year old car. easy convert.
Beautiful car man! Do you have any pics of your alternator brackets? Did you find one from a vendor or did you fabricate your own?
Thanks
 
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