# Ford 9n grounding



## voncalvin

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.


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## Fedup

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.


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## voncalvin

Thanks, helps a lot.


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## willys55

12 volt systems are always negative ground, positive ground for 6 volt


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## startinghandle

hello willys 55
it is incorrect to say 12 volt systems are always negative ground


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## willys55

yes


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## HomicidalBeaver

Follow the leads to their termination . On a 12 volt system the 12 positive goes to the solenoid.


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## deerhide

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.


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## big job

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..
sam


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## deerhide

willys55 said:


> 12 volt systems are always negative ground, positive ground for 6 volt


wrong!


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## willys55

Well, don't just say wrong, offer up some proof.


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## willys55

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.


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## z445guy

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


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## deerhide

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.


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## willys55

Keep in mind, we were discussing whether or not 12 volt system had positive ground........the


z445guy said:


> 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


24 volt systems did if I remember correctly. At least the M923A1 I drove was.


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## willys55

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.


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## PSJ

startinghandle said:


> hello willys 55
> it is incorrect to say 12 volt systems are always negative ground


Totally agree, there were 12 volt positive ground systems. PJ


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## big job

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


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## deerhide

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.


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## PJ161

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!


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## The Old Home

Done a lot of 12v conversions on Ford Tractors. Negative Ground. Google 12v conversion for a ford 9n/2n/8n. There are a lot of really good helps out there.


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## Yukon 60

In my opinion it would be a negative ground system, especially if you are now running a delco alternator and a 1 wire system. If you were to hook that up as a positive ground, I believe you would be smoking the system, the alternator at least.


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## Fitter

Buy a multimeter for $20-$40 watch a few you tube videos if you don't know how to use one. There indispensable, you could set set it to ohms scale found out in seconds which batt lead was ground.


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## Buckisland

Hello

My father purchased several military surplus trucks in the late 40’s when I was only 9 years old.

When I got older he explained to me why some of them were 6 volt positive ground and some were 6 v negative ground.

It seems there was a dispute between the Navy and the Army as to which was correct. The Nave trucks were wired one way and the army trucks were wired the other way.

So the 6V trucks we had both positive ground and negative ground.

The when Chrysler started using alternators I went to a training class about them the 12V system were negative ground.

I was recently involved in the purchase of a 1967 Kaiser Jeep M35.

It is 24V and has an alternator charging system.

Before hooking up the batteries I called several alternator repair companies and they assured me there are no positive ground alternators.

Buckisland


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## pogobill

I have two 6 volt tractors, an 8n positive ground and a Cockshutt negative ground!


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## Ed Williams

deerhide said:


> 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.


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## Ed Williams

My 54 NAA was originally 6 volt positive ground. I changed it to negative ground with the 12 volt conversion.


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## Ed Williams

My 54 NAA was originally 6 volt positive ground. I changed it to negative with the 12 volt conversion.


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## John Liebermann

Ed Williams said:


> My 54 NAA was originally 6 volt positive ground. I changed it to negative with the 12 volt conversion.


Ford was positive ground including the 9N, 2N, 8N, cars and pickups of that era, and I think even my 860.

Since electricity actually runs from negative to positive Henry probably thought that was the correct way to wire the vehicle. General Motors was always negative ground but I think Chrysler was positive ground.

The battery itself has nothing to do with whether the vehicle is positive or negative ground. Regardless it has to be wired the way the vehicle wants it to be positive or negative ground the battery does not control it


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## Ed Williams

deerhide said:


> 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.


My 53 Ford NAA was positive ground from factory. Changed to negative ground with 12v conversion


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## Dewayne Keeton

startinghandle said:


> hello willys 55
> it is incorrect to say 12 volt systems are always negative ground


T


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## Dewayne Keeton

This is true and not all 6 volts are positive.


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## John Liebermann

Dewayne Keeton said:


> This is true and not all 6 volts are positive.


Correct, GM was 6V Neg Ground


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## LouNY

Interesting, I've read thru this thread a couple of times it's been in existence for a few years now,
and I'm surprised no one has mentioned checking the coil to see how it is installed.









As you can see in a negative grounded system the coil negative goes to ground thru the points,
in the same vein if it was a positive ground system the coil positive would go to ground.


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## Sam Sevier

voncalvin said:


> 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.


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## Sam Sevier

The positive terminal on the alternator must be connected to the positive terminal on the batter and the negative battery able to the Tractor chassis. This is not show in the above diagram.


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## Sam Sevier

Fedup said:


> 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.


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## Sam Sevier

The most certain way to check is to find the other end of the battery cable, If it is connected to the chassis it is the negative cable for a + 12 volt system. A inexpensive multimeter is good for the application, use the ohm setting to measure resistance to the chassis. I should be less than 1 ohm for a good connection.


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## John Liebermann

A point about the coil. I cant remember ever checking this out by test, but I don't think it makes a difference if the coil is wired incorrectly so it may not be a good indicator of how the system is grounded. 

In the case of these older non solid state systems the biggest component dictating polarity has to be the alternator. 

Im not even too sure a generator cares about polarity,, would someone comment please.


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## LouNY

Coil polarity seems to have an effect on how well an engine starts and runs.
I have seen engines that didn't run just right with no other changes start working better when the coil was installed with the proper polarity. Why else do the put they + and - on them.


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## John Liebermann

LouNY said:


> Coil polarity seems to have an effect on how well an engine starts and runs.
> I have seen engines that didn't run just right with no other changes start working better when the coil was installed with the proper polarity. Why else do the put they + and - on them.


Lou, I agree with you re how the engine runs. Since it does run albeit poorly, it maybe would not be a good indicator of vehicle polarity.

The secondary circuit of the coil is completed thru the input primary. I've never completely(or partially) understood that. So,, if a coil is installed backward the secondary circuit would complete thru the point side of the primary winding, possibly making firing erratic I would think.

Edit: Explain better secondary winding


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