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| | | | Joined: Jan 2010 Posts: 32 New Guy | | New Guy Joined: Jan 2010 Posts: 32 | I have a 56 gmc with pontiac engine and a 12 volt system which has a postive groung. When charging the battery do i still go positive to positive with charger to battery? seems logical thanks for help tom  | | | | | Joined: Dec 2006 Posts: 1,464 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,464 | | | | | | Joined: Mar 2006 Posts: 1,703 Shop Shark | | Shop Shark Joined: Mar 2006 Posts: 1,703 | Yup that is how I have my battery maintainer hooked up on my "positive ground" 67 Triumph motocycle....works just fine.
Tim | | | | | Joined: Apr 2005 Posts: 1,971 'Bolter | | 'Bolter Joined: Apr 2005 Posts: 1,971 | Yes, Just make it a habit to check the water/acid level before hooking up battery chargers. | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 |
Are you referring to an original GMC 1956 V-8 (maybe a 316 or 324)?
I think that all 12v GMC electrical system were negative ground.
Through 1955, all GMC 6V 6-cylinder electrical systems were positive ground. In 1955, GMC 8-cylinder electrical systems were 12v negative ground (except V-8s in school buses were still 6v).
Chevrolet changed to 12v for all engines in the 1955-2nd series trucks.
| | | | | Joined: Jul 2007 Posts: 461 Shop Shark | | Shop Shark Joined: Jul 2007 Posts: 461 | Seems to me the 1956 GMCs were negative ground, as I think all GM vehicles were by that time. But I don't have any specs on the GMCs.
Harvester | | | | | Joined: Feb 2004 Posts: 29,747 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,747 | On passenger cars, all the manufacturers standardized their electrical systems at 12 volt negative ground in 1957. There were a few 12V + ground systems in 56, notably Ford, Nash, and Packard, not sure about GMC. Commercial trucks like Freightliner kept the positive ground up through the mid-1960's with the idea it made for more reliable grounding and less galvanic corrosion, especially where aluminum and steel were used together.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | As Harvester posted, all GMC trucks went to 12v negative ground for all engines in 1956 ( See page 16 ). | | | | | Joined: Feb 2004 Posts: 29,747 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,747 | If there's a reference to ground polarity on page 16, I haven't found it yet.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Dec 2006 Posts: 1,464 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,464 | Yeah, I don't see it either, and what difference would that make anyhow? The original post says it's pos. ground, and he wanted to know how to hook up a charger. I believe him, it's pos. ground.
Even if the literature of the day says ALL units converted to neg. ground on such-and-such a date, from what I've seen, there always are exceptions to the rule. | | |
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