points vs. hei
Team Owner
Joined: Jul 2008
Posts: 23,419
Likes: 22
From: In limbo
St. Jude Donor '13-'15, '17 thru '22
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Did he? I didn't read it that way. He just stated he converted a points dist to pointless. Whether it was 100% relevant to points or HEI discussion is another matter but I must confess that when I saw your reply my 1st thought was "what a smart .ss". But now I see that you intrepeted his text differently than i did and it makes sense.
Tech Contributor
Joined: Jun 2004
Posts: 20,847
Likes: 959
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
It is the wire that connects the ignition key electrical bus to the coil + terminal. It has a slight amount of resistance (I don't recall the exact number, probably in the 1 - 2 ohm range) to limit the peak current that will flow in the coil primary circuit.
Team Owner
Joined: Jul 2008
Posts: 23,419
Likes: 22
From: In limbo
St. Jude Donor '13-'15, '17 thru '22
Thanks, now I know which wire it is (and I didn't jack with that one on my car, so I haven't dorked up the circuit.....yet). I still don't think I get how it limits the voltage though, because the yellow wire from the starter motor to the coil + is hot with 12V, and is connected at the same point, so it seems like the primary circuit is still seeing 12V. That is why I was wondering if it was the black wire from the negative side of the coil to the hot side of the points, it seems like that location would limit the voltage to the points, which is what I thought the purpose was. Also, given what is here, it would appear I gave someone bad diagnosis advice a week or so ago.
Burning Brakes
Joined: Jan 2006
Posts: 1,152
Likes: 23
From: Kawartha Lakes and PEC, Ontario
Thanks, now I know which wire it is (and I didn't jack with that one on my car, so I haven't dorked up the circuit.....yet). I still don't think I get how it limits the voltage though, because the yellow wire from the starter motor to the coil + is hot with 12V, and is connected at the same point, so it seems like the primary circuit is still seeing 12V. That is why I was wondering if it was the black wire from the negative side of the coil to the hot side of the points, it seems like that location would limit the voltage to the points, which is what I thought the purpose was. Also, given what is here, it would appear I gave someone bad diagnosis advice a week or so ago.
Team Owner
Joined: Jul 2008
Posts: 23,419
Likes: 22
From: In limbo
St. Jude Donor '13-'15, '17 thru '22
The yellow wire...(on mine it's cloth-covered) should only have 12V when cranking. The resistor wire provides power when the car is running. The resistor is black, a little stiffer than the others and if your eyesight is good (and your harness is like mine) it says 'resistor' in small purple script on the wire.
Tech Contributor
Joined: Jun 2004
Posts: 20,847
Likes: 959
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Thanks, now I know which wire it is (and I didn't jack with that one on my car, so I haven't dorked up the circuit.....yet). I still don't think I get how it limits the voltage though,It doesn't. It's an old wive's tale that refuses to die on this forum. 
because the yellow wire from the starter motor to the coil + is hot with 12V, and is connected at the same point, so it seems like the primary circuit is still seeing 12V. Yes. The vehicle electrical system is 12 volts. Everywhere. I repeat, everywhere. That is why I was wondering if it was the black wire from the negative side of the coil to the hot side of the points, it seems like that location would limit the voltage to the points, which is what I thought the purpose was. Also, given what is here, it would appear I gave someone bad diagnosis advice a week or so ago.
because the yellow wire from the starter motor to the coil + is hot with 12V, and is connected at the same point, so it seems like the primary circuit is still seeing 12V. Yes. The vehicle electrical system is 12 volts. Everywhere. I repeat, everywhere. That is why I was wondering if it was the black wire from the negative side of the coil to the hot side of the points, it seems like that location would limit the voltage to the points, which is what I thought the purpose was. Also, given what is here, it would appear I gave someone bad diagnosis advice a week or so ago.Now, the starter shunt wiring. This circuit does not "increase the voltage to the coil". That is another wive's tale. This shunt circuit bypasses the ballast resistance to allow a coil current compensation when the battery voltage DROPS during cranking, particularly during cold weather cranking. At low battery levels the coil current will drop, possibly not allowing sufficient energy to allow an ignition spark to occur, so the current limiting ballast resistance is shorted out to try to help bring the coil current back up to the levels it was when the engine was running and the alternator was keeping the system voltage at 13-14 volts.
That is how the points system works. Again, notice how there is no mention of any voltage limiting part in the ignition system.
