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Technical 1954 Ford Positve Ground Vs Negative Ground

Discussion in 'The Hokey Ass Message Board' started by anothercarguy, Oct 2, 2021.

  1. A buddy of mine has a restored 54 Ford COE (239 Y-block) with 6v positive ground electrical. He's having electrical issues (battery drains, generator not charging, no fuses, most of the wiring is routed through the ignition switch to name a few issues) that he's asked me to troubleshoot and work on for him. Because my mind automatically thinks in terms of negative ground, I'm tempted to re-wire the truck with negative ground and add a small fuse block etc. (the wiring harness is new and was replaced by someone else). Is there an advantage to negative vs positive ground? Why did all the major car mfg's go to negative ground shortly after this time period?
     
  2. nosford
    Joined: Feb 7, 2011
    Posts: 550

    nosford
    Member

    Some 6V cars were negative ground and some were positive ground, the electrons don't care which way they go as long as there is a complete circuit. When everyone switched to 12V (1955 for Gm, 1956 for Ford, 1967 for VW) I think most of the US manufactures all went to negative ground, some off shore stayed with positive ground. When accessories like fancy radios and record players with TRANSISTORS came along they cared about + and - and it became easier for manufactures to get items like this in negative ground as that seems to be what all the electronics industry adopted. Just a guess on my part. Mark
     
  3. Positive ground is supposed to be better for corrosion.

    not sure, the switch to 12 volt negative was I think just to standardize stuff.

    I had a 53 Chrysler that was 6 volt positive ground I switched it to negative ground by flipping the wires on the coil and a couple other things , all in all about a 1 hour job.

    I think it would be advisable to rewired your buddies car negative ground and with fuses
    Simply as it’s been the norm since the mid 50’s snd just easier to work with .
     
    Last edited: Oct 2, 2021
  4. joel
    Joined: Oct 10, 2009
    Posts: 1,986

    joel
    ALLIANCE MEMBER

    My 41 p/u is positive ground with a new wire harness. After installing the new wiring I was able to track down the battery drain problems. Here is a list of items that were bad or not functioning properly:
    2 new voltage regulators not set correctly, rear bushing in generator wore out, starter button shorting to ground (rust inside), stop light pressure switch ground leak, ignition switch also had bad contacts.
    None of these problems occurred because of a positive ground system, as far as I can tell.
     
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  5. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,668

    gimpyshotrods
    ALLIANCE MEMBER

    Yeah, starters seem to not really care about voltage, so long as you are not staying on the switch until you kill it. Horns too.

    On every 6V to 12V conversion that I have done, the starter stayed, with the warning that in the future it might need to be replaced. Then again, that is true with about any starter.

    Nobody ever came back to complain. I still see many of these cars out and about. Never a mention of the starters.
     
  6. tubman
    Joined: May 16, 2007
    Posts: 5,852

    tubman
    ALLIANCE MEMBER

    I don't see how a change in ground polarity will help solve the problems mentioned "battery drains, generator not charging, no fuses, most of the wiring is routed through the ignition switch to name a few issues". Those problems should be solved in their own right, not by an attempted polarity change.
     
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  7. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,668

    gimpyshotrods
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    The post WWII largess and new-found wealth drove people to seek more luxury.

    Luxury in automobiles means accessories, or more standard features. All of those add up to a higher power demand. That pushed automakers to improve charging systems, and to place pressure on battery manufacturers to improve batteries.

    So what does that have to do with grounding?

    The archival explanations that I have been able to find all mention roughly the same thing: The radio. As the complexity of the vacuum tube and the surrounding circuit design increased it became more efficient to use a negative ground and a positive plate supply. When tube based radios were installed in cars it was much simpler to tie the negative battery terminal to the chassis then to electrically isolate the radio on a positive ground.
     
  8. RodStRace
    Joined: Dec 7, 2007
    Posts: 2,700

    RodStRace
    Member

    As tubman says, ALL the issues are due to changes and deterioration to the electrical system after manufacture, not polarity. Think of it as negative ground and fix it the same way you would if it was that way. Once everything is fixed, connect the battery.
    I once had a guy swap work with me. I had to fix his 50s truck that was messed up like yours. First, every added loose wire was removed. Then basic ignition, starting and charging were traced and made clean and connected properly. Last the accessories (lights, horn, radio, gauges) were run, using original wire if still present.

    As for why, here are some thoughts.
    https://mechanics.stackexchange.com...he-tradeoffs-for-positive-vs-negative-ground#


    EDIT: This is for a regular truck, but should get you darn near the finish line
    https://1954ford.com/forum/viewtopic.php?f=32&t=3018
    https://1954ford.com/forum/viewtopic.php?f=20&t=3164
     
    Last edited: Oct 2, 2021
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  9. Budget36
    Joined: Nov 29, 2014
    Posts: 7,218

    Budget36
    Member

    I’d think the battery goes dead because as mentioned, the generator isn’t charging.
    But is the battery going dead over night, in a week, an hour?

    start with cleaning all connections and the surfaces they attach to as well.

    As mentioned, if you plan on putting new battery cables on, don’t use AP shelf items, make or have made up some good thick gauge cables.
     
    anothercarguy likes this.
  10. Thanks guys...yes the plan is to troubleshoot one system at a time until I find the drains. I understand that changing the polarity isn't going to solve the issue (just makes it easier for my automatic negative ground thinking mind) If there is no advantage to switching, I'll just need to re-calibrate my mind ;).

    I know the generator not being connected is not helping the situation...but based on the info supplied by my buddy, the batteries (2 6v connected in parallel) go flat overnight after being fully charged so something is drawing them down. I'm also considering adding a marine isolator switch so he can run on battery #1, #2, both or turn them off.
     
  11. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,668

    gimpyshotrods
    ALLIANCE MEMBER

    Two fully charged batteries in parallel going dead overnight is a pretty serious drain.

    What condition are the batteries in?
     
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  12. Budget36
    Joined: Nov 29, 2014
    Posts: 7,218

    Budget36
    Member

    Have your buddy charge the batteries. Wait an hour after charge and check the voltage on them.
    Then wait 24 hours and recheck the voltage.
    Do this with the batteries disconnected from the car.
     
  13. RodStRace
    Joined: Dec 7, 2007
    Posts: 2,700

    RodStRace
    Member

    Here is a post I wrote for another thread, it applies here. Fix the drain, clean connections as much as you can and fix any obvious messes.
    https://www.jalopyjournal.com/forum...n-san-francisco.1204990/page-50#post-14127355

    The polarity is just in your head. If it makes it any easier, just reverse the leads on the meter (Red to ground, Black to +) and you will connect the same and see the same results.

    Once the issues are found and fixed, it should not need the cutoff, but would add a measure of protection and peace of mind.
     
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  14. nochop
    Joined: Nov 13, 2005
    Posts: 2,300

    nochop
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    from norcal

  15. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,602

    Ebbsspeed
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    Yes, it is a serious drain for sure. IF these are GOOD batteries, they should be disconnected until the issue is found and resolved. Good batteries going down that fast are creating HEAT somewhere in the wiring. Too much heat and the COE will become COokEd.
     
  16. Happydaze
    Joined: Aug 21, 2009
    Posts: 1,173

    Happydaze
    ALLIANCE MEMBER

    I thought it was the other way around, reverse polarity if you will, ha ha! I could equally be mistaken though!

    I recall my first car, 1966 Morris Minor, was 12v positive earth / ground, and the white fury stuff that would mysteriously grow on the battery terminal, I forget which, was crazy.

    But the corrosion thing, as I understood it, was to do with the car body itself. Some kind of electrolytic deterioration. I never was a great scholar of physics!

    Swapping to negative earth was simple enough (no rewiring, just a repolarisation of the dynamo, aka generator), and 'modern' negative earth radios could be fitted! Only upmarket cars had radios in the UK in those days.

    Chris
     
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  17. Lots of great advice...thanks. I'll pass along the advice to keep the batteries disconnected until he brings the truck to me for troubleshooting. I'm not going to get at this for another 3-4 weeks. I'll check in with my findings once I get at it.
     
  18. big john d
    Joined: Nov 24, 2011
    Posts: 255

    big john d
    Member
    from ma

    pull the positive terminal off and connect a test lamp between the cable end and the battery terminal if the lamp lights you have a draw start disconnecting things one at a time leave them disconnected when the light goes out what you just disconnected is the draw then leave that disconnected and reconnect everything back one at a time if the lamp lights that is also a draw
     
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  19. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,602

    Ebbsspeed
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    Nope. Think about it. Ever use an electric oven? Ever started a diesel or an R/C airplane engine with glow plugs? Those devices are not a "dead short", yet they get hot enough to light a fire.

    Lots of heat can be generated when there is a resistive short (Or as you say later in your comment "a big short").
     
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  20. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,608

    Rusty O'Toole
    Member

    If it is fucked up fucking it up worse won't fix it. Leave it positive ground and change whatever the last guy fucked up back to stock then go to work diagnosing and fixing the problems properly.
     
  21. BJR
    Joined: Mar 11, 2005
    Posts: 7,143

    BJR
    Member

    GM went to 12 volt negative ground in 1953 for the new Buick V8's, Cadillac, and Oldsmobile V8's. Chev and Pontiac went to 12 volt negative ground in 1955 with the new V8's.
     
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  22. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,025

    Mr48chev
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    On the drain= take your volt meter and check across the top of the battery with the negative lead on the meter connected to the negative post and probe around the top with the + lead. Dirty battery tops can cause a drain. I've seen a 9.5 volt drain across the top of a 12 volt battery in the dirt and moisture before. On one that was stumping folks because the battery would go dead in two hours.

    There are plenty of instructions out there to see how to correctly check the output of a 6 V positive ground Ford generator.

    I have to agree with RodStRace all too often electrical issues that drive you crazy are due to add on items on the rig. Extra wires for items that sometimes are no longer there. Micky mouse hookups for trailer connections, extra lights.
    Still bad connections on wires and cables are normally an issue. Do the simple stuff first, Make sure that the battery top is clean and that the battery posts and cable ends are clean. Make sure that every connection on the battery cables are clean and tight and that the areas on the block /engine that the ground goes to is clean bare shiny metal. Especially if the engine has fresh paint that can be an issue.

    Use your meter to make sure you have full power to the inside. Some times the main power feed system makes two or three stops with new wire taking of from a connection to the next connection.
     
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  23. joel
    Joined: Oct 10, 2009
    Posts: 1,986

    joel
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    @gimpyshotrods , Thanks for the info on the the factory switching from pos. to neg. ground. I learn something new on here all the time.
     
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  24. RodStRace
    Joined: Dec 7, 2007
    Posts: 2,700

    RodStRace
    Member

    One more thought before you get the truck and dive in.
    Restored truck with new wiring and equipped with a generator/regulator.
    We are used to buying a new part and bolting it on.
    Was the generator/regulator polarized properly?
    https://powertoolsgeek.com/how-to-polarize-a-generator/
     
  25. buick bill
    Joined: Dec 18, 2008
    Posts: 707

    buick bill
    Member
    from yreka;ca

    i have hooked up ovens backward before . keeps everything cool once you reverse the polarity
     
  26. OahuEli
    Joined: Dec 27, 2008
    Posts: 5,095

    OahuEli
    Member
    from Hawaii

    If you change ground polarity you will need to reverse the leads on your DC frequency meter.
     
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  27. Budget36
    Joined: Nov 29, 2014
    Posts: 7,218

    Budget36
    Member

    ? Can you explain. Or did you mean volt meter Or ammeter?
     
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  28. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,079

    Doublepumper
    Member

    Never seen a DC frequency meter in a Ford. Reversing the ammeter input is something that will need to be done if changing polarity, or the meter will read backwards.
    It's been my experience, a faulty voltage regulator can cause the battery to drain with the car elect. off. Sticking contacts and corrosion is something to check on.
     
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  29. manyolcars
    Joined: Mar 30, 2001
    Posts: 8,510

    manyolcars

    The best reason for negative ground is so you can give and receive jumpstarts
     
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  30. OahuEli
    Joined: Dec 27, 2008
    Posts: 5,095

    OahuEli
    Member
    from Hawaii

    No such thing as a DC frequency meter, its Buick Bills fault about hooking up his oven.:D:rolleyes:
     
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