9N 12 Volt conversion resistor question

[Hick-From-Hell]

MY 9N front mount distrubator does not like to start when I have the both resistors wired up (the big white resistor and the wire type resitor that changes as it gets warm) when I remove the white resistor that comes with the kit it starts and runs great but with it it will hardly start and runs rough. Do I need that white resitor?

 

[JMOR]

(quoted from post at 15:58:43 10/04/10) MY 9N front mount distrubator does not like to start when I have the both resistors wired up (the big white resistor and the wire type resitor that changes as it gets warm) when I remove the white resistor that comes with the kit it starts and runs great but with it it will hardly start and runs rough. Do I need that white resitor?

aybe not. Depends on whether you have the old original 6v coil or have replaced it with the 'so-called' 12v coil Old is about 0.5 ohms & "12v" is about 2.5 ohms. With the higher resistance coil. you do not need the additional resistor. Even if you do need it, as with an old 0.5 ohm (6v) coil, you need to verify the white resistor's value.........those run all over the map & if it is too large a resistance it may result in producing your symptoms.

 

[Hick-From-Hell]

I used the new "12 volt" coil that came with the conversion kit off this website. Should I measure the resistance of it? or just leave it out since it runs so much betteR?

 

[JMOR]

(quoted from post at 16:15:48 10/04/10) I used the new "12 volt" coil that came with the conversion kit off this website. Should I measure the resistance of it? or just leave it out since it runs so much betteR?

easure it for peace of mind if you like, but IF YT did their stuff right, then it will be a 2.5 ohm coil & you can chunk the white resistor.

 

[Turnaround]

The resistor/s is used to limit the current (amps) across the points. Points can only handle up to about 4 amps, and at the max of 4 amps, the points do not last real long. The resistor/s should be wired so that the starter circuit bypasses the resistor and supplies full battery voltage when the starter is cranking. Then, once you let go of the starter, the engine"s coil should be wired through the resisitor/s. Put an ammeter in the wire with the coil"s primary wire and use enough resistors (including the coil"s own resistance) so that the points are carrying less than 4 amps. One caution here, be sure to have clean points when doing this check, as slightly burned points will produce some additional resistance, and all resistances add together to give the final point amperage.

 

[JMOR]

(quoted from post at 17:00:22 10/04/10) The resistor/s is used to limit the current (amps) across the points. Points can only handle up to about 4 amps, and at the max of 4 amps, the points do not last real long. The resistor/s should be wired so that the starter circuit bypasses the resistor and supplies full battery voltage when the starter is cranking. Then, once you let go of the starter, the engine"s coil should be wired through the resisitor/s. Put an ammeter in the wire with the coil"s primary wire and use enough resistors (including the coil"s own resistance) so that the points are carrying less than 4 amps. One caution here, be sure to have clean points when doing this check, as slightly burned points will produce some additional resistance, and all resistances add together to give the final point amperage.

e doesn't have such an option on his old "N" tractor.
"The resistor/s should be wired so that the starter circuit bypasses the resistor and supplies full battery voltage when the starter is cranking. "

 

[Turnaround]

I bought two coils from a tractor dealer, and one coil from Charlotte, NC (all in one week) before I got one that would work with out overheating the points (by supplying too much amperage). Problem was the offshore repo coils just didn't have enough wire in them compared to the quality coil. The cheapo coils would start with full battery voltage, but they burned the points like right away. Installing the resistor to save the points, I found the cheapo coils would not start. The good coil worked just fine with Ford's wiring diagram (which supplies full voltage when cranking and resisted voltage when running). The cheapo coils had very little ohm readings compared to the good coil.

 

[Anonymous-0]

If you are using a "12V" coil, you can use the original resistor that was on the 6V system and everything should be OK. If you are using a 6V coil then you need an additional resistor to limit the current. Be sure that the coil supplied in the conversion kit is 12V.

 

[NOXJohn]

You may want to look at Hobo's web site and gut out an old square can front mount coil so you can use a real 12 volt no resister needed oil filled round coil. A real 12 volt coil takes all the resistance measurement out of the conversion and you will have a much tougher coil. It is not that difficult of a job and well worth it in my opinion.