Datsun Roadster Forum-311s.org

Had my first break down today, no spark when I flicked the points so replaced coil with a random 12v my roommate had and started right up.

My old one was reading 14.6k and 4 ohms. Is that far enough out of spec to cause a no spark?

Stock points should have a total of around 3 ohms as I understand it. Ballast resistor is 1.6 oms and coil is about the same. I just bought two NGK coils direct from NGK for backups and two resistors from Nissan. Coil should state use with resistor.

Undo the neg wire at the coil with the pts closed you should have a solid ground , test with a multi meter it should be nearly the same as a wire that length. 20 ohms ?
If you're low on amps ,through it . the spark can be weak as to not make it passed the coil windings insulator it's working but needs better current flow I used a 1156 bulb and socket w/ wires
Installed instead of a coil to see how it lit ...check all the lowbs ,see it really In action easier than the meter and leads
Spark shrinks in compression and humidity shrinks it compoundedly
If you have good ohms readings a new condenser is a good next step and check the braded ground in distrib .

Curtis wrote: Fri Aug 13, 2021 11:00 am Stock points should have a total of around 3 ohms as I understand it. Ballast resistor is 1.6 oms and coil is about the same. I just bought two NGK coils direct from NGK for backups and two resistors from Nissan. Coil should state use with resistor.

Interesting, guess I can blame the coil then (it was also hooked up to the ballast resistor so another 2.5 ohms resistance over stock probably would be enough to kill the spark).

I look at your diagram every day!

The training centers use 1- 20 ohms usually as a ok connection. The common coil's not high amp though..
Sound as it's connected , likely it's burnt thru or the insulated piece cracked ,or carbon tracked ruining the high V spark
Anybody have the alum beer can around there coil ?