Ballast Resistor For Ignition Coil

[Tham]

I've noted that since I switched over to an electronic ignition system
on my KE70's 4K, the engine runs much hotter than usual, presumably
due to a higher coil output voltage and hotter spark.

I had bought the distributor module with built-in ignitor, plus a
resistorless coil, from a salvage yard some time ago. I think it
was a stock unit on the 5K engine or the Starlet's 4K-E. The coil
looks like one of those high output coils.

The coil does not use any external ballast resistor. I wonder if adding
back a ballast resistor in series to the coil's positive terminal, as with
a normal external resistor-type coil, might reduce the secondary
output voltage, a somewhat weaker spark, and thus help the engine
to run cooler.

[toyoda]

If the Engine is running Hotter its not the coil.

Suggest you check the timing as this is the most likely cause.

If you use a coil that needs a resistor without one - it will eventually overheat the coil - not the Engine.

Toyoda

[Tham]

Thanks for the reply.

The timing has been set the same as before, when points
were being used.

I've been told that most of these electronic ignition coils
have higher output voltage and hence give a hotter spark.

[litldv8]

hotter is probably a bad term
fatter or simply has more energy because of superior design is more correct
recheck your timing
how are you doing this?
are you using a timing light or static timing it?
neil