9n coil

[ffinmich]

Hi, I have a 9n converted to 12v. Is
there a simple way I can check the coil
to see if it's 12v or 6v coil.
Thanks

 

[JMOR]

(quoted from post at 11:14:44 02/09/22) Hi, I have a 9n converted to 12v. Is
there a simple way I can check the coil
to see if it's 12v or 6v coil.
Thanks

es, accurately measure the primary winding resistance.

 

[Bruce (VA)]

With an ohm meter.

Put it on the lowest scale. Hold the probes tightly together to see the resistance of the probes themselves. Subtract that reading from your coil reading.

Then measure the resistance on the primary circuit, post to pig tail. If it's 2.25 ohms or more, it's a 12v coil. Less than 2 ohms, usually 1.5 ohms, it's 6v. The OEM Ford coils are usually less than 1 ohm.

12v or 6v coil, you always need the oem ballast resistor on a front coil. See tip # 30.
75 Tips

 

[tractorguy2]

Odds are if you have a square coil. you have a six volt.

 

[ffinmich]

Checks 2.7 so must be 12v. Thanks for all the responses.

 

[Tim PloughNman Daley]

A coil can be 6V or 12V so don't assume if a square coil for a front mount it is 6V. Bruce(VA) has the easiest method listed. Picture below shows how to test a front mount square coil with a VOM. Set meter to OHMS; touch probes to coil contacts - polarity doesn't matter - as shown. Touch one probe to pigtail contact on bottom, other probe to coil terminal top post. A 6V coil should read approx 1.5 OHMS static, a 12V coil about double that. That doesn't guarantee the coil is good; you need a sophisticated, expensive test unit to do that. If ignition switch was left on and points were closed, probably melted the tar inside the coil and once it gets hot will fail. There a 2 or 3 correct ways to wire a 9N for 12V and a thousand incorrect ways. Which do you have? 99.98% of all non-starting issues are due to incorrect wiring regardless if 6V or 12. A 9N/2N 12V switch out job should be: 12V BAT; OEM GENERATOR removed, 12V ALT installed with a belt tensioner; the OEM Roundcan Cutout Circuit is removed; and the OEM BALLAST RESISTOR must be used with both the 6V and a 12V system. If you use the OEM 6V coil with a 12v job, you need to add an external 1-OHM ceramic resistor or equivalent in the in-line coil wire circuit. If you swap the 6V coil out for a 12V coil, you do not add the external resistor. User error #3 is many do not know what the OEM Ballast Resistor is and what the roundcan cutout is. They are totally different animals. Know which is which via manuals. Wait, you're not done. Either system is dependant on the front mount distributor and if it is timed, tested, and mounted correctly on the engine. DIST mounts one correct way and if it is forced down 180 DEG off, it will damage the base and render it junk. The DIST CAM & WEIGHTS have a male tang that is OFFSET and when mounted correctly on engine, must mate with the OFFSET female slot on the cam shaft face. Many fellas do not know this, is one of the top non-starting reasons with the front mount, and when they damgag the DIST and it won't start, assume they need to switch to 12V. RULE: If t won't run on 6V, what makes you think it will on 12V? Just saying. There is nothing wrong with 12V, and there's nothing wrong with 6V; they both have their Pros and Cons. The most important thing is that whatever system you choose to use, you have it wired correctly. A good wiring harness is essential. Good, clean battery cables are essential. A 6V battery uses heavier gauge cabes. A 12V battery uses the smaller diameter gauge battery cables like used on your car or truck. Finally, regardless if you use a 6V/POS GRN setup with a GEN and Cutout or if you use a 12V/NEG GRN setup with a 1 or 3 wire ALTERNATOR, you must use a fan bet tensioning device on it otherwise you will never charge the battery, failure #2 on wiring jobs. Your ESSENTIAL MANUALS have all the OEM 6V Wiring Diagrams. JMOR's Pictograms have all the correct 6 and 12V wiring diagrams.


FORD N-SERIES FRONT MOUNT COIL TEST:

FORD 9N/2N TRACTOR WIRING PICTOGRAMS by JMOR:

FORD N-SERIES TRACTOR FRONT MOUNT DISTRIBUTOR, AND CAM SHAFT:

NOTE: OFFSET TANG AND SLOT.

N-SERIES FRONT MOUNT DISTRIBUTOR WHEN MOUNTED 180 DEG OFF:

FORD 9N/2N TRACTOR ESSENTIAL OWNER/OPERATOR/PARTS/SERVICE MANUALS:

Tim Daley(MI)​