Ignition Timing Lights & Positive Earth

[John and Suzanne Payne]

I have a Series IV Alpine with Pertronix ignition and positive earth.

– Will a regular induction timing light work to set the timing?
– Would it have be attached with negative to earth as is usual or positive lead to earth to match the cars system?
– Would the induction pick-up for the plug lead have to be attached facing a different way to account for the spark running the other way on positive earth?
– Is it possible to damage the timing light if connected incorrectly?
– Any recommendations on a suitable timing light to buy?

[Joe and Kerch McConlogue]

My timing light is nearly as old as my Alpine, but it has two power leads, positive and negative as well as the inductive pickup. With an incandescent lamp it is not sensitive to orientation of the inductive pickup. Modern lights if using LEDs might be direction sensitive, but I’m not familiar with their circuitry. No harm done, if it doesn’t work in one direction, just turn it around. I’m sure those with more info will chime in.

[Sean Johnson]

It doesn’t matter for the induction lead… place the red power lead on ground, black on coil or brown wire terminal on fuse box. Just set the timing on a Big Healey yesterday.. they are all originally Positive ground.

On the pertrox unit… somethings they don’t tell you… you have to use resistor spark plug leads.. Using stranded metal core wires will fry the amplifier unit. you should use their coil and remove the ballast resistor from the circuit. the pertronix coils are internally ballasted. if you use their coil and keep the OE external ballast the voltage signal to the amplifier will be insufficient for proper operation.. been there, done that!

[Bob and Jean Webb]

I have to agree with Joe. As far as using a Pertronix in place of the points on an Alpine I have always used a Lucas coil, ballast resistor and a set of Lucas plug wires from the early 70’s. When it goes to a SUNI I install plug wires that were a set of NOS when I bought them in the early 80’s. I don’t use them other than for being judged.

[Author]

Posts