Coil Question

NCmau · Aug 3, 2018

52 8N, Alternator w/external regulator. In assembling this engine together, I noticed the coil is marked with an inscription that needs a resistor. There is no resistor that I can see anywhere in this tractor. So I don’t know what the wisdom was by the previous owner of running the tractor with this coil. Unless I am missing something, this coil would provide too much current and eventually burn the points. I am not at the stage where I can measure electrical readings yet but I think should need a coil with a built in resistor. What you think?

JMOR · Aug 3, 2018

(quoted from post at 10:49:29 08/03/18) 52 8N, Alternator w/external regulator. In assembling this engine together, I noticed the coil is marked with an inscription that needs a resistor. There is no resistor that I can see anywhere in this tractor. So I don’t know what the wisdom was by the previous owner of running the tractor with this coil. Unless I am missing something, this coil would provide too much current and eventually burn the points. I am not at the stage where I can measure electrical readings yet but I think should need a coil with a built in resistor. What you think?

arking on coil says it needs resistor. What is the question?

Bruce (VA) · Aug 3, 2018

" What you think? "

I think you need to go to NAPA and buy p/n IC14SB. That's a coil w/ 3.25 ohms internal resistance suitable for 12v applications & no external resistor required.

Or, do exactly as JMOR & the label said; go to NAPA and by a dropping resistor . The resistor you will need depends on the internal resistance of your coil. See tip # 30.

" Unless I am missing something, this coil would provide too much current and eventually burn the points."

You are.

Points don't care about 6v or 12v. Ever see different part numbers for 6v or 12v points? Using your current coil on 12v will eventually burn up the coil, not the points.

" I think should need a coil with a built in resistor."

No automotive coil has an ?internal resistor?. Internal coil resistance is determined by wire gauge and the number of turns. Higher resistance is provided by smaller gauge wire with greater turns. If the coil is marked or sold with a notice ?requires an external resistor? that simply means it has a low internal resistance and will be damaged by excessive voltage. It does not mean the coil has an internal resistor.
75 Tips

NCmau · Aug 3, 2018

Tip #30: 3.25 ohms internal resistance coil…. Thanks!

Coil Question

NCmau

Member

JMOR

Well-known Member

Bruce (VA)

Well-known Member

NCmau

Member

Similar threads