Vac advance & ign timing problems

[240ZMan]

Low voltage = high current

Actually, in this case this isn't true. If you are seeing a significant voltage drop before the coil (in other words, the voltage across the coil is much less than 12V, it's because there is additional resistance in the circuit elsewhere. That means the TOTAL resitance of the circuit is higher, which means the circuit's current is LOWER. This really works against you with the coil because you have both a lower voltage across it as well as lower current flowing through it. Power is equal to the voltage times the current. In this case you will have significantly less spark energy.

Where your statement is true is IF the total POWER of the circuit is to remain constant, THEN it will take a higher current with a lower voltage to generate (or consume) the same amount of power. That's the idea behind low voltage lighting in your backyard.

EE class dismissed

BTW, what is the gap of your spark plugs? I think stock is supposed to be .035" (going from memory) and you can open it up to .040 with a higher voltage coil.

[Murph]

Yeah of course, makes sense....I should have known that. :nervous:

From memory, I'm getting ~ 5V to the coil with the balast resistor, so I'll give it a crack with the resistor bypassed....see how I go.

[Murph]

Bit of an update...

It had started to miss again occasionally, so I finally got around to bypassing the ballast resistor....no probs after that. I still haven't got around to sorting out the sticky vac advance, so it's still unhooked. Also, I'm pretty certain the centrifugal advance isn't working correctly either, as timing will jump around from time to time. By golly though, when it does get into just the right spot, this thing has top end power like I've never seen it have before! Ran like that once for a week or so (good week that one ), then dropped the top end again.

You can really hear the difference in the engine note, between it running well and running crap. Gets a much more urgent and serious bark to it.

Hopefully in a few weeks when I have some time I'll strip the dizzy back and rebuild it.