9N coil burnt !

[RayinVA]

I need some electrical advise on my dad's 1940 9N that I restored over the past year with lots of help from this forum..Thanks... I returned it to the farm last month and it was used a few times until it wouldn't start because of the lack of spark. Noticed that the coil was cracked. Is this due to an old coil,,,or too much voltage. As shown on the wiring diagram I placed the resistor inline with the coil. I bought the resistor at a ford tractor dealer so I think it is the right one for the converted 12 volt system.. Could anyone tell me what the resistance should be between the ignition switch and the coil (with the resistor)?? I will check the resistance when I go to the farm next week. the diagram from the ford dealers shows a second resistor inline with the first one.. should I place two of the same resistors if the resistance is not high enough?? thanks for your comments.
ray

 

[JMOR]

(quoted from post at 21:39:24 07/01/11) I need some electrical advise on my dad's 1940 9N that I restored over the past year with lots of help from this forum..Thanks... I returned it to the farm last month and it was used a few times until it wouldn't start because of the lack of spark. Noticed that the coil was cracked. Is this due to an old coil,,,or too much voltage. As shown on the wiring diagram I placed the resistor inline with the coil. I bought the resistor at a ford tractor dealer so I think it is the right one for the converted 12 volt system.. Could anyone tell me what the resistance should be between the ignition switch and the coil (with the resistor)?? I will check the resistance when I go to the farm next week. the diagram from the ford dealers shows a second resistor inline with the first one.. should I place two of the same resistors if the resistance is not high enough?? thanks for your comments.
ray

If original 6v coil, then the original Ford `12250 ballast res isn't enough. If the so-called 12v square can coil then it is enough. The original 6v coil was about 0.5 ohm primary & replacements anywhere from about 0.5 to 1.5 ohms, where the "12v" coils are about 2.5 ohms.

 

[souNdguy]

if oem coil.. then dash resistor plus conversion resistor are needed.

soundguy

 

[RayinVA]

Thanks... Can you tell me what a Dash Resistor is? Can I get it at Radio Shack,,,,or the ford tractor dealer???

I will get a coil today.. If its an OEM coil I'll get a Dash resistor and the ballast resistor... If it's not an OEM coil,, then I'll go with the ballast resistor only...

thanks,
Ray

 

[souNdguy]

the front mount fords used a resistor mounted ont he back of the dash.. it's in the parts manual

soundguy

 

[JMOR]

Ray, I gave you the part number 3 days ago...and it is still 12250.