Pertronix Ignition

[fordtrucks4ever]

I picked one up when they first came out for positive ground systems. Today I decided to maybe install it. Reading over the instructions it clearly states there should only be two wires attached to coil. The wire from module(-) and wire to chassis(+). It mentions nothing about the tach wire going back. Any concerns here??????

 

[GregW]

Hi Terry,
The tach wire (which is also the switched hot lead) goes to the black wire on the Pertronix unit. Step #12 in the directions.

 

[Michael Oritt]

Greg--

Please do not confuse us by referring to the directions!

 

[GregW]

My bad. :laugh:

 

[mjobrien]

Picked up one from Advanced Dist. and with the standard wiring harness for a Pos ground 100/4 I had to hook it up as such...

Hope this helps.


Michael.

 

[fordtrucks4ever]

According to step 12 in the directions it reads as follows: Connect an insulated AWG 20 copper stranded wire from the positive coil terminal to the positive battery or chassis. How can this be the switched hot lead?????

 

[GregW]

Here is the link to Pertronix. ignitor12vpos You mentioned you got the unit a while ago. Maybe they rewrote the instructions between then and now. Sorry for the confusion.

 

[Bob_Spidell]

If I'm reading the schematic right, this ignition is always hot (when the ignition switch is on) due to the wire from the coil to the block. This is because on a points car, the white/black wire grounds the coil--disabling spark--when the battery cutoff switch is 'Off,' and the block is connected to battery ground when the switch is 'on.'

If you remove that wire and move the white/black wire on the battery cutoff switch to the same terminal that connects the battery to ground--you'll need a larger connector--then the master switch will open the circuit to ground when the MS is 'Off' and the car can't start, and the white/black wire will provide a suitable ground when the switch is 'on.'

 

[GregW]

Hi Bob,
I see what you're saying.
White/black wire (harness from battery switch) to + side of coil.
Black/white wire from Pertronix to - side of coil.
Ignore new ground wire altogether.

 

[Bob_Spidell]

Yep, but you have to move the white/black wire on the cutoff switch to the same terminal that connects the battery to chassis ground, else the the coil circuit will be open when the switch is 'on' and you'll get no spark. I wired my BJ8 with Pertronix this way, and it preserves the 'anti-theft' aspect of the cutoff switch; even if you hotwire the ignition--no problem on a Healey--and try to push-start the car it won't run if the cutoff switch is 'Off.'

The Pertronix people are good, but I don't think they know you have a dandy ground lead already available in Big Healeys with the coil ground on the cutoff switch (which is wired in parallel with the points--hence the spark kill). The principle is the same in piston aircraft with magnetos--since mags are always hot, the only way to kill spark is to ground the primary coil (with a wire called a 'P' lead).