Size of the 8ne10306 dropping resistor

It's dropping about 6 Volts, and carrying a current of about 4 Amps, so it's dissipating at least 24 Watts.

That is why if is so difficult to select the right Ballast Resistor. If you select one that is to large the circuit current will decrease and your ignition will be marginal. If you select one that is to small the ballast will overheat and fail.. this "may" cook your coil.

The Out of Circuit Resistance of the 8ne10306
ballast should measure ~1.7 Ohms but that assumes that the the coil used is a 6v OEM Front Mount (.75 ohm).

The way that I would measure the (in circuit) 8ne10306 resistor is to measure the voltage drop across the OEM Ballast (Known Response Curve) to determine that the circuit operating current is ~ 3 amps. If the Voltage drop is ~ 3.5V across the OEM ballast you have a good match.

NEVER USE A FIXED RESISTOR IN PLACE OF A BALLAST THAT IS GREATER THAN DELL'S .5 OHM

Hope this helps,

Any autoparts store will usually have their own product line version of 12-to-6volt conversion resistor. Often used for 6-volt heater fan motors; windshield wiper motors; instrument panel gauges; sometime old fashoned vacuumtube radios. Leave alone the necessity of 6-volt squarecan ignition coils..... ...Dell

Is that ohms measured?

I don't know the thermal properties of the resistor.. if it is temp stable, you could take an inline amp reading.. a voltage measurement.. then fairly accurately calculate ohm value.

If it is not a temp stable resistor.. the you could do that same test twice.. one when cold, and one hot.. then establish an ohm range, based ona stable votlage, and the other units varrying.

Tolerance will also be an issue on the resistor, I've seen many power resistors that have fairly high tolerance range.. 20% or more.

Soundguy