Countryss Posted March 30, 2009 Report Share Posted March 30, 2009 hey guys, I am planning on replacing some old wiring that runs for the head lights and the brake lights and signals (you get the point) My question is what gauge wire to use. This car is still operating on a 6 volt system. Quote Link to comment Share on other sites More sharing options...
steveplym Posted March 30, 2009 Report Share Posted March 30, 2009 I would use at least 12 gauge. I'm pretty sure that was the factory wiring. If you look in a shop manual and go up to the '49 or '50 diagram it gives you the gauges. 12 would work well. Quote Link to comment Share on other sites More sharing options...
Countryss Posted March 30, 2009 Author Report Share Posted March 30, 2009 thanks i wasnt sure. I dont own a shop manual either and figures that a bunch of you guys do. appreciate it. Quote Link to comment Share on other sites More sharing options...
dezeldoc Posted March 30, 2009 Report Share Posted March 30, 2009 14 gauge is more than fine 12 ga is to big, that is what is used on the charging circuit. Quote Link to comment Share on other sites More sharing options...
Young Ed Posted March 30, 2009 Report Share Posted March 30, 2009 OEM is 12g for 1 of the 2 power wires to the headlights. Thats presumably the high beam wire. The charging circuit uses 10 or 16. Quote Link to comment Share on other sites More sharing options...
TodFitch Posted March 30, 2009 Report Share Posted March 30, 2009 If cost is no option, then the larger diameter (lower gauge number) the better. I had a 1957 VW Beetle back in the 1970s. Used 8 gauge where 12 was called for and 10 gauge where 14 was called for. And got rid of those crappy OEM fuses (put in American style Buss fuses). Made a big difference in the lights on that 6v car. OEM sized wire is okay and adequate but you can, if you want to pay the extra cost, so better. The one thing you don't want to do is use wire sized for a 12v system. Quote Link to comment Share on other sites More sharing options...
steveplym Posted March 30, 2009 Report Share Posted March 30, 2009 That is what I was thinking Tod. I tried to use as much larger wire on my car as I could where needed. I had and still have plenty of 10 and 12 gauge. Now I have converted to 12 volt so I guess it doesn't matter as much. Quote Link to comment Share on other sites More sharing options...
Countryss Posted March 30, 2009 Author Report Share Posted March 30, 2009 thanks. now how do I tell the difference between wire for 12v or 6v system Quote Link to comment Share on other sites More sharing options...
Young Ed Posted March 30, 2009 Report Share Posted March 30, 2009 you need heavier wire for 6v. My advice is to wire for 6v and then it will be good enough for both. If you wire for 12 you are stuck with 12 Quote Link to comment Share on other sites More sharing options...
Countryss Posted March 31, 2009 Author Report Share Posted March 31, 2009 gotcha. but what I mean is when i go to the speed shop tell them I need whatever gauge wire for 6v? Is that how it works? Or by going with a lower gauge signify that it will be suitable for 6v Quote Link to comment Share on other sites More sharing options...
TodFitch Posted March 31, 2009 Report Share Posted March 31, 2009 thanks. now how do I tell the difference between wire for 12v or 6v system Wire is pretty much wire. Forgetting RF frequencies, the cross-sectional area determines how much resistance there is for DC loads. The larger the area (larger diameter) the lower the resistance. The lower the resistance the better, especially for 6v loads. A 6v load of the same power draw needs twice the current as for an equivalent 12v load. You can do the math but basically the wire must be much lower resistance for a 6v system to run efficiently. The other factor is how high the breakdown resistance is for the insulation. And basically that is much higher than 12v so you can use it for either 6, 12 or even 120v systems. The other factor on insulation is how well it stands up to the environment it is in (abrasion, chemicals, etc.). Modern plastic insulated wire is pretty good in the auto environment. In the old days the insulation was rubber which abraded easily so they covered it with cloth for abrasion resistance. Rubber also breaks down when exposed to ozone (ignition level voltages generate ozone) and petroleum products (grease and oil). Finally rubber and cotton cloth oxidize with age. So basically everything about your old car was bad for having the old wire lasting. Grease and ozone from the start and now 50 (or in my case 76) years of oxidation. If you get a reproduction wiring harness from a place like YnZ's or Harnesses Unlimited it will have modern plastic insulation covered with cloth to make it look period correct. It is actually better quality wire than the original because it has a better material for insulation. All this is just a long post to get around to saying that on a car the difference between 6v wire and 12v wire is how thick it is. And that you can use "6v wire" on a "12v car" and all you are out is the extra money for buying the more expensive (has more copper in it) wire. Quote Link to comment Share on other sites More sharing options...
Countryss Posted March 31, 2009 Author Report Share Posted March 31, 2009 wow. thanks that sums it up!!! Quote Link to comment Share on other sites More sharing options...
greg g Posted March 31, 2009 Report Share Posted March 31, 2009 The other day I posted a link to Rebel wire who is making a basic 8 circuit wiring harness suitable for 6 V applications. Should be down the forum, as Saturday post. Quote Link to comment Share on other sites More sharing options...
dezeldoc Posted March 31, 2009 Report Share Posted March 31, 2009 Strange yesterday I pulled out all the wiring on the 50 and most of it was 14ga & 16ga. with the exception of the charging circuit that was 10ga & 12ga. Why is it if their is a differance between 12v and 6v systems, that the harness I got says will work for 12v or 6v? and it is meant for 12v. Quote Link to comment Share on other sites More sharing options...
Countryss Posted March 31, 2009 Author Report Share Posted March 31, 2009 well im not planning on changing the whole harness just the front lighting wires Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted March 31, 2009 Report Share Posted March 31, 2009 I rewired a 1939 Desoto with modern wire and used 14 guage wire for the car. I used the 12 guage wire when I was coming off the stater motor to bring the current over to the headlight relay you can use 10 g here. There is not difference for wire verus 12 v or 6v in reference to gage. Gage is a standard measurement for wire thickness. The lower the number the thicker the strands. In 6v you should always have a lowere number. Also remember that back in the 30 some of the wire was steel an not alwasy cooper. I found this in my headlight wires. Also of not for your lights make an extra wire as a ground wire this will improve your lighting and also insure that if you painted something in the headlight and tailght area you will always get the lights to work. My tailights were working and then had to have the rear fender painted and then lost the stoplight. It was the loss of a good ground. Grounding is very important with a 6v system. As stated before the companies that are reporducting wires looms are using modern wire coated with palstic and then a cloth covering. The old cloth covered wires just had the cloth over the wires and when the water would break down the cloth you lost electric power. Use modern wire if this is a driver and then go for the newer wire harness if going for AACA or show car. Quote Link to comment Share on other sites More sharing options...
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