coil wire upgrade?
Moderators: FORDification, Thunderfoot
- RebelRider
- Preferred User
- Posts: 295
- Joined: Fri Feb 09, 2007 7:16 pm
- Location: Missouri, Monett
coil wire upgrade?
Can you replace the resistance wire that feeds voltage to the coil with a resistor? The insulation on mine is about shot.
- 68F250
- Blue Oval Guru
- Posts: 1174
- Joined: Thu Jul 22, 2004 3:26 pm
- Location: California, Brea
re: coil wire upgrade?
Is it the coil wire in the engine compartment? If it is, that's just plain wire. If it's the resistance wire under the dash in the harness, you can buy resistance wire to replace it at the auto parts store, look for 1.3 ohm resistance wire.
You can also replace the resistance wire with a ballast resistor. A regular resistor is not the same, the resistance wire and the ballast resistor have a positive tempco (temperature coefficient). As it heats up, the resistance goes up. It's a compensation factor built-in to regulate the coil voltage. You need this for a couple reasons, when an engine idles the coil is in saturation and heats up but a positive temco will heat up and cut down the voltage. When the engine is turning rpms, the coil is out of saturation and the temco cools down allowing more voltage to the coil. Same thing happens with the supply voltage from the battery, with high charging voltage the temco heats up and cuts down the excessive voltage. When the charging voltage comes down the temco cools and allows more voltage.
Even if you did use a regular resistor and ignore the tempco, it would have to be rated at least 25 watts.
You can also replace the resistance wire with a ballast resistor. A regular resistor is not the same, the resistance wire and the ballast resistor have a positive tempco (temperature coefficient). As it heats up, the resistance goes up. It's a compensation factor built-in to regulate the coil voltage. You need this for a couple reasons, when an engine idles the coil is in saturation and heats up but a positive temco will heat up and cut down the voltage. When the engine is turning rpms, the coil is out of saturation and the temco cools down allowing more voltage to the coil. Same thing happens with the supply voltage from the battery, with high charging voltage the temco heats up and cuts down the excessive voltage. When the charging voltage comes down the temco cools and allows more voltage.
Even if you did use a regular resistor and ignore the tempco, it would have to be rated at least 25 watts.
Barry
"Are you gonna make it all 220?"
"Yeah 220, 221, whatever it takes."
"Are you gonna make it all 220?"
"Yeah 220, 221, whatever it takes."
- RebelRider
- Preferred User
- Posts: 295
- Joined: Fri Feb 09, 2007 7:16 pm
- Location: Missouri, Monett
re: coil wire upgrade?
Yes it's the wire under the dash.
Thanks for the info Barry!
Thanks for the info Barry!