> Henry Ford was positive ground until 1956 on all of his autos,
> way back in
> the 19 teens he stated the plugs fired much better and current flowed
> better, quite a few of my Henry Ford books states his theory on
> the plugs as
> the main reason for + ground.
Of course, he also believed in Hitler ...
Turns out you can wire the coil to give any spark polarity you want, it
really doesn't matter which pole of the battery is wired to ground. That's
why you switch the coil wires when you change the ground polarity.
I believe other people have theorized that positive ground reduces
electrolytic corrosion of the frame and body. I've heard it was White
Trucks that did an actual study of this, which claimed to show reduced
corrosion with + ground, and I know Mack was still supplying + ground trucks
in the 70s, so that might well be the (historical) reason for those military
trucks to be positive ground. John Deere and many other heavy equipment
makers also continued to use positive ground for a long time, although AFAIK
they're mostly negative ground today.
Personally, I think the main reason for positive ground is that one side of
the battery has to be grounded, and positive is just as good as negative.
There really wasn't any reason to change, and there was a mixture of both
systems in common use, until electronics started being found in cars.
GM/Delco was the "300 pound gorilla" at the time and they used negative
ground, so gradually negative ground became the standard. Negative ground
does work slightly better when building electronics, especially vacuum tube
electronics, but it's not a huge difference.
Randall
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