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 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.

Nope. That coil is designed to run no ballast resistor, adding one will potentially stuff your coil.

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 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.

 

If you want a weaker spark, why bother swapping to electric dizzy?

 

I'd say the temp issue would be more to do with timing than anything else. Considering you changed dizzy, its possible the timing is out.