One way is to install one of these. http://www.summitracing.com/parts/PRF-70107/ It has a relay that switches four circuits with the ignition key and also has three always on circuits. I used the original coil wire (with the resistance wire) to switch the relay. The reduced voltage was sufficient to operate the relay. One of the switched circuits provides 12V to the coil and another powers the electric choke. One of the always on circuits provides power for the horn relay and another will provide power for the headlight relay(s) some day. Still thinking about how to power a Taurus electric fan. The fan needs more than the 20Amp circuits from the added fuse box.
Great idea... just us a bosch relay to power the ignition. Energized/actuated with the original ign wire. Run a 10 ga. wire to the relay from the battery, inline fused, then relay positive to the the coil. Negative from the battery to the Relay. Easier than finding a wire under the dash, and it will be substantially higher voltage than ancient and small dash wires. I did my headlights already the same way, with two relays one for the high beams one for the low. They are white hot! Here is a link I saved that illustrates the relay wiring. http://www.classictruckshop.com/clubs/earlyburbs/projects/bosch/foglites.htm In case it's not clear, when + power is given to the 85 terminal, then the + battery at terminal 30 is connected internally to 87 terminal which is what ever accesory you want to turn on. Head lights, Fan or Pertronics Blaster coil. Use at least 10 gauge wire for Fan of headlights, 12 or 14 or maybe 16 to the coil. Terminal 86 is 12 volt negative. The unused 87a terminal is hot (12v +) when the relay is NOT active/energized/on, and dead when it is on. Dont use it.
I have read this in other places on the forum. I tested my distributor power supply wire on my '73, and had a steady 12 volts to the distributor. I just pulled the points distributor out of my car about 2 months ago to replace it with the Pertronix distributor. I didn't have to by-pass any wires, or run any wires to get 12 volts. What's up with the cars that have less than 12 volts supplied to the distributor? It seems like, with my '73 being a factory points car, that it would also have less than 12 volts going to the distributor also. Anybody got any input?
I thought our cars had 12 volts going to the coil, and used an internal resistor coil, which is why they didnt have a ballast resistor. I know other fords, earlier model, had a resistor wire going to the coild instead of a ballast resistor. Its been so long since ive worked on a stock maverick i could be totally wrong though.
Resistive wire, my 73 gets about 9 volts, but the Pertronix II works down to 6 or something like that..
I assume the there is a ballast wire in the ign circuit to the coil. If so it would be part of the harness under the dash. It would be connected to the C term on the switch and run to the firewall connector. If you wanted to bypass it just parallel it with another wire spliced to it at both ends and just leaving it that way. You could always remove it to reinstate the ballast. Adding a relay triggered by the ign wire to power the Pertronix would work very well. Even with a lowered voltage through the ballast would not be a problem as most relays have a low drop out voltage so the reduced voltage would still activate the relay without problem. One thing to know about the Pertronix modules. The Pertronix I is designed for stock coils. Use of a high performance coils 'could' damage the module due to their lower resistance. The 'II' is designed to handle the lowered coil resistance so is a better choice in terms of max reliability. I believe the III also can handle the lower reistance coils. RS
You won't see a voltage drop across a resistor (e.g., resistor wire or ballast resistor) unless current is flowing. In a points distributor, if the points are open, no current is flowing and you'll see 12V at the coil. If the points are closed, current is flowing and you'll see the lower voltage. Try measuring it with the engine running.
I will try that, thank you. When I tested my distributor power supply line, I tested the unhooked end of the wire itself, with the ignition switch in the on position, just before I installed the distributor. Was that not a sufficient way to do so?:Handshake
Resistor wire will have no effect because no current is flowing. You'll see battery voltage that way. With the engine running, there will be battery voltage when the primary coil circuit is open and the reduced voltage when circuit is closed. When you measure it with the engine running you'll be getting an average of the two.
Thank you for the information. I will surely try it with the engine running. If the distributor has less than 12 volts going in to it, can it still make the amount of output power it is advertised to make?
I've run both the Pertronix I & II. The only difference I saw was the II didn't develop a missfire after a "thru the carb hiccup backfire" on cold starts. That required you to kill the ignition and restart the engine to cure it. (reboot the unit I presume). I've also run the Crane XR-1, it works as well as the Pertronix II. All are extremely reliable.
Don't know. Its been discussed here. Try a search or you might call the tech line of the manufacturer. Maybe someone will chime in.
everyhting i have worked on or owned i have converted. I think the its best thing you can do for these old motors hands down. Should be the very the first thing you do. Unless you have a old 6volt system then upgrading to 12 volt should be first then the petronix system next.
