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Featured Ford 9n grounding

Discussion in 'Ford 9N/2N/8N' started by voncalvin, Oct 7, 2017.

  1. voncalvin

    voncalvin New Member

    Oct 7, 2017
    I have a Ford 9N which has been converted to 12 volts and has an altenator. It has no battery and both cables are red. How can I safely determine if it is still positive ground or been converted to negative ground.
  2. Fedup

    Fedup Registered User

    Feb 25, 2014
    On top post batteries the positive post is slightly larger than the negative. Cable ends/terminals are also made to reflect this size difference. For example, a positive cable end will be sloppy loose on the negative battery post and may not actually tighten up without extra effort while the negative end will be hard to fit onto the positive post. Try your present cable ends ONE AT A TIME on your new battery and see which one fits which post better. Then make sure the negative battery post is the one now connected to ground.
    sixbales likes this.

  3. voncalvin

    voncalvin New Member

    Oct 7, 2017
    Thanks, helps a lot.
  4. willys55

    willys55 Caractacus Potts Staff Member Supporting Member

    Oct 13, 2016
    12 volt systems are always negative ground, positive ground for 6 volt
    sixbales likes this.
  5. startinghandle

    startinghandle New Member

    Oct 31, 2017
    hello willys 55
    it is incorrect to say 12 volt systems are always negative ground
  6. willys55

    willys55 Caractacus Potts Staff Member Supporting Member

    Oct 13, 2016
  7. HomicidalBeaver

    HomicidalBeaver New Member

    Nov 7, 2017
    Follow the leads to their termination . On a 12 volt system the 12 positive goes to the solenoid.
  8. deerhide

    deerhide Retired Canadian

    Those old Fords were neg. ground; 6volt original or 12 volt conversion. The positive cable from the battery goes to the starter. The battery polarity is checked by: positive post having a + symbol near it or coloured red, but a top post one is always larger.
  9. big job

    big job New Member

    Nov 21, 2017
    Most alternators are negative ground. Engine ground cable to - neg
    on battery + pos cable to fat plus terminal on battery. All you have
    to do is swap two terminals on the ampmeter so it shows charge..
  10. deerhide

    deerhide Retired Canadian

  11. willys55

    willys55 Caractacus Potts Staff Member Supporting Member

    Oct 13, 2016
    Well, don't just say wrong, offer up some proof.
  12. willys55

    willys55 Caractacus Potts Staff Member Supporting Member

    Oct 13, 2016
    and just for the info, 12 volt batteries are designed to charge the plates across the plates from positive to ground. The 12 volt battery would need to be completely discharged to the state of being an empty vessel, then using a battery charger without "smart charge" technology you could slowly trickle charge it reversed, but, for all intents and purposes, the battery will be ruined. The plates are designed with the positive plates being lead dioxide, and the negative being composed of a sponge lead, which would now be reversed. Because the reversed battery is no longer formatted correctly, it will only work to a limited degree and eventually fail completely.
    FredM likes this.
  13. z445guy

    z445guy Active Member

    Mar 10, 2017
    Willys55 if my memory serves me correctly back in the late sixties and early seventies some big rig trucks had a positive ground charging systems on them

    Sent from my iPad using Tractor Forum
  14. deerhide

    deerhide Retired Canadian

    Ford, GM and Chrysler changed to 12volt in the mid fifties,the old 6 volt systems were neg. ground. Early British imported cars(to N A) were pos ground, both 12 and 6 volt, they changed to neg. ground in the 1950's too. German and French cars were neg. All the NA farm tractors I have seen , 12 and 6 volt, were/are neg.
    British, French, Spanish, Italian and Russian imported tractors(I can only remember back to the 1950's)6v and 12v. were neg. ground. However some 2nd. hand, grey market tractors, imported from the UK were pos. ground when they got here. I don't know much about lawn and garden tractors but all I have seen were neg. ground. I don't doubt there are exceptions though.
  15. willys55

    willys55 Caractacus Potts Staff Member Supporting Member

    Oct 13, 2016
    Keep in mind, we were discussing whether or not 12 volt system had positive ground........the
    24 volt systems did if I remember correctly. At least the M923A1 I drove was.
  16. willys55

    willys55 Caractacus Potts Staff Member Supporting Member

    Oct 13, 2016
    in any event though, DC systems are not like AC, unlike AC which has one live wire until a circuit is completed.....DC has 2 live wires, and the system doesn't really care which direction the current flows. The original design of automotive batteries prior to the early 50's was basic and easily converted to either positive or negative ground. However 12 volt batteries were developed to handle the needs at that time, prior to the early fifties automobiles and tractors for that matter had lower compression ratios and required little effort to spin them over to start, however the 6 volt batteries would struggle to start a hot engine because of their weak design and CA being low. The standard for the early 12 volt batteries was to go to negative ground, I remember seeing a transcript at the Interstate Battery factory for a radio show commercial back in 1950 that discussed the "new Technology" coming to the american automobile. It was in a nice display in the lobby of the factory.
  17. PSJ

    PSJ Dusty

    Sep 20, 2011
    Totally agree, there were 12 volt positive ground systems. PJ
  18. big job

    big job New Member

    Nov 21, 2017
    Most autos were 6vt pos grd. and most if no all: Gm were neg grd.
    (thats in my lifetime). In general about all went to 12Vt neg grd in
    1956. Out of high school I worked in my uncles bus co. The Flxible
    always had 12 vt. pos ground up to I think 1957 and after. We had a
    White W28 12 vt pos grd 1956. So back to ya post your tractor was
    6vt pos grd right; someone put alternator right; most likely a run of
    the mill GM neg grd alternator. so ya block cable color it black goes
    to neg small terminal starter cable color it red fat terminal on battery.
    Now find out if somebody put a solonoid in which origional used a
    contact push with ya foot button. My push with foot took a dump
    so I put 12vt solonoid and a push to start button on the dash 12vt
    neg grd. all I did was swap wires on ampmeter to show charge...sam
  19. deerhide

    deerhide Retired Canadian

    As far back as I can go to have 'hands-on' experience with old Ford tractors is 1941, at least that is what the title said, probably a 2n, it was my Aunt's when I was a 'lil kid (early 50's)then later my cousin's. It was 6 volt neg. ground then and later on changed to 12v neg. It had a Delco 12v generator on it when I took it in trade on a new MF 255, that was probably 1985.
  20. PJ161

    PJ161 PJ

    Sep 12, 2016
    Aside from 4 tractors and one is a converted Ford, my hobby is British MG sports cars, I have now a restored 1955 MGTF 1500 and it's positive ground as factory, by merely changing a couple wires, as to ammeter, coil and replace the fuel pump, I can just switch cables on the battery and it becomes negative ground. This is a common conversion for anyone who wants to use standard negative ground electronic equipment on the car, nothing needs to be done to the battery, just switch cables. Never heard of a positive ground alternator bought off the shelf, a special one can be bought from an English firm for about $400.00. PJ

    Oh yeah, all Ford cars in the 40s were positive ground!