positive ground cars

[mrspeedyt]

what american cars were positive ground ... and what years? my '41 de soto and '40 la salle is positive ground. the '23 buick is negative.

[De Soto Frank]

Prior to the 12-volt changeover in '53-'56, the majority of American vehicles were Positive-Ground.

Major exceptions were:

Buick, Chevy, Olds, Pontiac.


MoPar, Ford/Merc/Lincoln, Caddy & La Salle, GMC, Packard, Nash, Hudson, Pierce, Studebaker were all positive-ground.

[W_Higgins]

Model T's were negative, but Model A's where positive, in one of those rare instances where Ford actually changed their standard for something.

[Jim_Edwards]

Model T's were negative, but Model A's where positive, in one of those rare instances where Ford actually changed their standard for something.

And all Fords through 1948 remained on the positive ground concept. The story is that Henry thought that electron flow not current flow should be the standard. I suspect his friendship with Thomas Edison may have had a lot to do with that.

[Skyking]

Metropolitans were pos. ground, although, most of us changed them to neg..... 2 of mine are still positive ground.

[mrspeedyt]

any advantage to positive ground?

[Silverghost]

Brittish cars were + positive ground for decades into the 1960s.

On a + positive ground car does the spark not jump in the opposite direction on the ignition point set and also the spark plugs ?

Why was the change eventully made to - Negative ground ?

[billybird]

At least the Model T ended on a "positive" note.

[Skyking]

I heard that there was less corrosion on + positive ground cars. I never noticed the difference.

[dei]

My (Dad's) 51 Nash Canadian Statesman is positive ground. My original 52 Ford flathead pickup is positive ground also.
As to rust, the Nash has almost 100,000 miles on it and with only ever having seen one winter of driving in it's life it still wears it's original factory paint so it does not have anywhere rust you would expect on a car with that kind of mileage.

[mrspeedyt]

any cars world wide that were 12v positive ground? (i know the brits were for the most part)...

[JD in KC]

Yes, 1955 Packard and Clippers were 12V Positive Ground.

[mrspeedyt]

found a good thread on the cadillac/ la salle club message forum 'reason for neg vs pos ground?' they got into the subject a little (actually... a lot...) deeper.

[W_Higgins]

How about a link?

[mrspeedyt]

I haven't yet mastered the art of posting a link. sorry...

[mrspeedyt]

http://www.cadillaclasalleclub.org/f...,109562.0.html hope this works...

[W_Higgins]

That works -- you done good.

[Skyking]

They stated what I had said, less corrosion.........

[W_Higgins]

Three pages and no definitive answer. Here another link that offers lots of theories and no answer:

Model T Ford Forum: Why the Switch to Positive Ground on Modren Fords?

I'd lean toward it being a battle of theories with no merit and it ending in standardization.

[mrspeedyt]

standardization DOES simplify things.... (at least a little... )

[Dandy Dave]

Somewhere around I have a Dykes Auto book from the mid 20's, In it is a list of negative and positive ground Vehicles dating back to the begining of batterys, charging systems, and starters. The list is quite long. Over all, with the number of cars listed the N&P Ground was about equal. Dandy Dave!

[De Soto Frank]

I heard that there was less corrosion on + positive ground cars. I never noticed the difference.

I never noticed a MoPar that rusted less than a Chevy of the same vintage / climate... have seen /owned very crusty examples of both.

[Skyking]

I never noticed a MoPar that rusted less than a Chevy of the same vintage / climate... have seen /owned very crusty examples of both.

Frank, I'm referring to corrosion in the electrical system. Battery post, contacts, etc.

[De Soto Frank]

Frank, I'm referring to corrosion in the electrical system. Battery post, contacts, etc.

I've encountered more than a few folks who expressed the theory that positive ground lessened chassis / body corrosion...


I'm trying to think if the battery terminals corrode less on my positive-ground cars or not... I run conventional lead-acid batteries in all my vehicles, 6 or 12 volt, positive or negative ground...

I don't think I recall seeing fluffy-white corrosion on the terminals of my positive-ground MoPars, but do see it frequently on my 12-volt negative-ground modern stuff, and seem to remember fluffy-white on my 6-volt negative ground Chevies...

One thing I have noticed on all my lead-acid batteries, regardless of polarity, is that the positive post & clamp tend to develop a hard, black coating, while the negative post and clamp just turn a dull-grey that brightens quickly with a few twists of the terminal brush.



Frank

[DavidAU]

I have read an article in one of my Rolls Royce Club magazines regarding extensive testing that Rolls Royce carried out in the early years (1915 - 18 I think) as they were observing problems with corrosion in the cooling system when cars were returned to the factory for service.
Rolls royce was a bit different to all other manufacturers in that most cars were returned to the factory for service or if that was not possible a company employee would go out to the car where ever it was in the world (the owner paid of course) so they had records of most cars and the problems they were having particularly as they started to age.

Henry Royce was a brilliant electrical engineer before he started Rolls Royce Motors and he had designed the electrical system with positive earth as this was the most efficent way for the electrical current to flow however their testing proved that this was what was causing the corrosion in the radiators, blocks, heads etc. and all the cars were changed to negative earth from that time on.
If I can find the article I will post it.

David

1923 Metallurgique Torpedo
1931 Rolls Royce Phantom 11 Continental
1940 Ford Deluxe Coupe
1947 Mercury Coupe