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Technical Explain to me about Positive ground

Discussion in 'Traditional Hot Rods' started by blazedogs, Mar 3, 2020.

  1. blazedogs
    Joined: Sep 22, 2014
    Posts: 445

    blazedogs
    Member

    Working on a old 60,s engine today . It calls for positive ground, in my case a British engine.. I have run into this in the past with other projects.The last one was a old farm tractor Mpls Moline . Have never known why this is. What makes it positive ground and for what reason ?? Gene
     
  2. 1-SHOT
    Joined: Sep 23, 2014
    Posts: 1,799

    1-SHOT
    ALLIANCE MEMBER

    Because electricity flows out of the negative post
     
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  3. VANDENPLAS
    Joined: Dec 14, 2009
    Posts: 2,377

    VANDENPLAS
    Member

    Battery positive is connected to the frame and negative is through the wiring.

    same principle as negative ground.

    you can switch to negative ground easily if you want

    switch the battery around
    Coil wires swapped
    Distributor depending on hei, electronic or points need to be switched

    ammeter if your still running one.


    No big deal about positive earth, other then it being different then what we are all used to.

    I think it was done for radio or ignition interference back in the day or some malarkey like that.
     
  4. VANDENPLAS
    Joined: Dec 14, 2009
    Posts: 2,377

    VANDENPLAS
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    that’s highly disputed both ways, not saying your wrong, but I cant answer that 100% either way as fact.
     
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  5. 1-SHOT
    Joined: Sep 23, 2014
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    1-SHOT
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    If you store a car and pull the positive cable off the battery it will discharge. If you pull the negative off you won’t have a parasitic drain on your battery
     
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  6. anthony myrick
    Joined: Sep 4, 2009
    Posts: 5,822

    anthony myrick
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    It’s for cars with reverse cut gears.
    Everything runs backwards
     
  7. 1-SHOT
    Joined: Sep 23, 2014
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    1-SHOT
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    Someone needs to take basic electrical and then advanced electrical at dealership. I got mine at Ford schooling in Carrolton Texas.
     
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  8. jimmy six
    Joined: Mar 21, 2006
    Posts: 6,390

    jimmy six
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    Because the Prince of Darkness...Mr. Lucas thought it was a good idea.:rolleyes:
     
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  9. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 2,355

    2OLD2FAST
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    from illinois

    I know that the way you reverse an? HO train is by reversing polarity , same with a fan motor and a golf cart , so how's that work with a DC starter motor ??
     
  10. That's what happens when you put the steering wheel on the right side.

    Phil
     
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  11. blazedogs
    Joined: Sep 22, 2014
    Posts: 445

    blazedogs
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    Yes, Jimmy 6 Right I,m impressed(Lucas)
     
  12. 500caddy
    Joined: Feb 8, 2019
    Posts: 78

    500caddy

    I have heard that with positive ground you won’t have corrosion on the battery posts


    Sent from my iPhone using The H.A.M.B. mobile app
     
  13. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,681

    Blues4U
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    from So Cal

    Electron's flow from negative to positive, but the flow of electricity is actually opposite that. As the electron's flow along a conductor, jumping from atom to atom, they leave an opening behind them. This is the "Hole Theory", which is the dominant theory of electricity. Hole movement IS electricity. While some people like to claim one or the other is correct, as a technician you can consider it either way.

    https://mste.illinois.edu/users/Murphy/HoleFlow/HoleFlow.php
     
  14. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,681

    Blues4U
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    from So Cal

  15. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,681

    Blues4U
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    from So Cal

  16. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,475

    seb fontana
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    from ct

    It doesn't care about polarity..To make a starter motor rotate in reverse the brush plate must be rotated 90°.
     
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  17. VANDENPLAS
    Joined: Dec 14, 2009
    Posts: 2,377

    VANDENPLAS
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    well, someone put some facts together!!!
    Thank you for that.
     
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  18. funny I was going to ask this eventually.....my 1956 Dodge - positive ground....had a 1954 Dodge Little Ram put in it....has always seemed to run okay around the yard with a little missing....never have done anything to the motor exceprt a carb refresh over the years.........had it maybe 20 years or so........
     
  19. Mimilan
    Joined: Jun 13, 2019
    Posts: 569

    Mimilan
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    Lucas is also responsible for the first intermittent wipers, and the self-dimming headlamp.
     
  20. Hemi Joel
    Joined: May 4, 2007
    Posts: 821

    Hemi Joel
    Member
    from Minnesota

    Electricity flows in a loop, so everything electrical needs at least 2 paths for the electricity for flow thru it. One path from the power source to the component, and another path back to the power source. When they build a car, they save wire by not running 2 wires (a + and a -) to everything. They run a cable from the battery to the chassis (ground). One side of each electrical component is either internally or externally connected to the chassis. (ground) Then only one wire to complete the circuit from each component to the battery. Now the electrical loop goes from the battery, thru the needed cables, fuses, wires, and switches, to the component, to the chassis, to the ground cable, to the battery. The only difference between positive ground and negative ground is wich side of the battery is connected to ground, as well as any polarity sensitive components.

    THere is nothing wrong with positive ground. No reason in the world to change it if you are keeping the stock electrical system in place. Just make sure to hook up the battery the right way, observe polarity when charging or jumping. If you want to run a neg ground radio or something, just add a converter, or isolate the component from ground.

    If you are swapping in a an engine with 12V negative stuff, you might want to convert the car over. Bulbs, starters, relays, solenoids, cig lighters usually work either way. Generators, alternators, radios, electronic ignition or electronic anything are polarity sensitive and need to swapped if you change the system. Heater fans you need to test, it could go either way. Obviously mechanical gauges are unaffected, but electric gauges probably need to be swapped if they are internally grounded, or rewired if they are externally grounded. Points don't care, swap the coil wires. I hope this helps.
     
    Last edited: Mar 3, 2020
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  21. lake_harley
    Joined: Jun 4, 2017
    Posts: 947

    lake_harley
    Member

    Lucas light switches have 3 positions; Off, Dim, and Flicker.

    Lynn
     
  22. Diavolo
    Joined: Apr 1, 2009
    Posts: 810

    Diavolo
    Member

    My understanding is that positive grounding increases galvanic response (rusting) of the body and cables where negative ground corrodes the terminals instead. Easier to fix.
     
  23. And warm beer.
    Bob
     
  24. Beanscoot
    Joined: May 14, 2008
    Posts: 1,409

    Beanscoot
    Member

    I thought the advantage of negative ground was because spark plugs worked ever so slightly better when the 'lectric jumped from the center electrode to the outside, or vice versa.
     
  25. 41rodderz
    Joined: Sep 27, 2010
    Posts: 4,722

    41rodderz
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    from Oregon

    I thought it was a persons attitude:oops:
     
    Last edited: Mar 4, 2020
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  26. Mimilan
    Joined: Jun 13, 2019
    Posts: 569

    Mimilan
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    That was from their refrigeration dept!

    At least their vacuum cleaners didn't suck
     
  27. BJR
    Joined: Mar 11, 2005
    Posts: 6,355

    BJR
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    What color is the sky in your world? This is just wrong.
     
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  28. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    Truck64
    Member
    from Ioway

    As far as electrons go, a spark "likes" to jump from hot to cold, the center spark plug electrode is far hotter than the ground electrode so consequently it takes less ignition coil energy buildup to start the spark from there.

    An ignition coil (transformer) will work either way it is wired, but it takes something like 20 to 30 per cent less energy to initiate the spark when wired properly.

    Interestingly enough this has nothing to do with whether or not the car is positive or negative ground!

    Don't really understand it (I just work here) and make sure my ignition coils are wired correctly. It probably wouldn't show up at idle, though maybe on a long uphill pull or hard acceleration, something like that.

    https://mgaguru.com/mgtech/ignition/ig104.htm
     
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  29. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    Truck64
    Member
    from Ioway

    I've learned not to discount crazy sounding shit. I haven't had any batteries discharge by being disconnected though.

    Carmakers (mostly) switched to 12 volt negative ground in 1956. Elvis was drafted not long after. So.
     
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  30. Boneyard51
    Joined: Dec 10, 2017
    Posts: 4,019

    Boneyard51
    Member

    Folks, when you disconnect either cable from your battery, it interrupts the circuit! Makes no difference which one you disconnect it will eliminate the parasitic draw! It makes no difference as to positive or negative ground as long as components are compatible! Some things are polarity sensitive, some are not. If you have a permanent magnet motor, simply reversing the cables will reverse direction. If you have wire wound field motor, you have to reverse the direction of the current in the fields to reverse the direction. That’s why some motors do and some do not! Simple!








    Bones
     
    Last edited: Mar 3, 2020
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