Pertronix vs. Points

herb65 · 11-03-2009, 11:25 AM

I have a 73 Mach 1 with the pertronix ignition.Lately I have been haveing some start and die issues resulting in me checking the voltage at the coil being 5 to 5.5 volts at idle.I jumped it using 12 volts to the coil and it works fine but the tach is inoperative, and would like to keep the factory tach working.Put the points back in and everything seems fine and runs just as well as with the Pertronix.My question is what is the real benifit of running the pertonix over the points?I have done a search and found many people like myself that keep a spare set of points with us in case the pertronix lets us set so why bother?! Thanks for any input.Herb

22GT · 11-03-2009, 11:34 AM

Quote:

Originally Posted by herb65

I have a 73 Mach 1 with the pertronix ignition.Lately I have been haveing some start and die issues resulting in me checking the voltage at the coil being 5 to 5.5 volts at idle.I jumped it using 12 volts to the coil and it works fine but the tach is inoperative, and would like to keep the factory tach working.Put the points back in and everything seems fine and runs just as well as with the Pertronix.My question is what is the real benifit of running the pertonix over the points?I have done a search and found many people like myself that keep a spare set of points with us in case the pertronix lets us set so why bother?! Thanks for any input.Herb

The operate full-time on 14V, you will need to bypass the resistance wire under the dash. You don't even need to cut it, just Scotchlock a connecting wire at the tach end of the pink wire, and at the firewall. If operation of the car is changing, though, something else may be happening.

pprince · 11-03-2009, 11:39 AM

The advantage of the Pertronix is that it always keeps its tune. Points wear and gradually get out of tune.

If you jumped the circuit that is why your tach was not working.

You can bypass the pink resistor wire under the dash to get the full 12 volts to the Pertronix.

daves67ss · 11-03-2009, 12:18 PM

Back in the day, my 67 would burn up a set of points in about 1500 miles. Never figured it out. Pertronix solved that problem. I had heard about the trick of the pink wire before I installed mine. So...I have no comparison with the lower voltage, but have never had an issue with the full 12 volts. Based solely on advise gleened from the VMF, I also carry the points in the trunk.
Dave

herb65 · 11-03-2009, 01:14 PM

Thanks Guys. What I did was leave the pink wire hooked up and jumped a wire from the bat to the coil and that worked fine except the factory tach did not function properly.If I run a bypass wire from under the dash to the coil my tach will not work right either. 22gt you are right that my voltage has dropped to 10.2 in the system with the lights on and years ago it would stay around 12 volts, so maybe a alt rebuild with a one wire conversion would keep voltage up enough to maintain 7 volts at the coil.Am I going in the right direction or chasing my tail!!Thanks for the help.Herb.

whisperer · 11-03-2009, 02:07 PM

Go to my site (click on the logo below) and go to "Tech" and then "Pertronix". Everything you need to know about how to do it right and why it doesn't work right now is there including diagrams.

66FastbackGT_T5 · 11-03-2009, 03:27 PM

Just to answer:

I have Pertronix build in to fire the car and a set of Points in a box in the trunk?

Why?

Pertronix just knows 3 states of work: On, Off, Scrap

Points can bring you home everytime, even with bad ignition

68RCodeConv · 11-04-2009, 09:37 AM

You have to fiddle with points periodically. Especially if it is a cheapo set.

Don't have to fiddle with Pertronix and gives a stronger spark.

Plus the latest version (Pertronix III) has a built in adjustable rev limiter.

79cobraII · 11-04-2009, 11:10 AM

+1 Points wear and gradually get out of tune.

And i should add that New points, "MADE IN CHINA" are god awful and wear beyond fast.

I took a 200 mile trip checked my points it was around 26 degrees, came back it was 37.

the next day i readjusted it back to 25. 1 week later it was 35 and i have maybe 50 miles on the car.

I just gave up. I really wanted to use points because i had a pertronix II go bad, then then the magnetic ring went bad and it was driving me insane. I figured the points wear but at least it was reliable.
unfortunately i came too late to the party, all the good points are long gone, and nothing is left but inferior import reproductions.

that is why we all keep points in the trunk or even an extra electronic ignition module.

I should also add, that my ignition system at the time was having a problem with electronic modules, the cars ignition was totally wonky. the points made it better. I later discovered my ignition wires were the source of my problem the entire time. once i switched them out for another brand, my issues went away and i could use my pertronixs again.
Its interesting how different everyone's car is. Example I ran a bypass in my car, and it ran WAY worse tons of miss. plus i couldn't use my tach, but i was getting 13+ volts to the coil.

i took the bypass out, and just used the resistance wire, and it worked

, (knock on wood) I know that the resistance wire can start to deteriorate over time. I've also heard that the high output coils that everyone is using can accelerate it. I know that high power coils Kill regular ignition wires prematurely. So i stick with regular voltage coils now. my car seems happier about it.

chpierce · 11-04-2009, 06:53 PM

Whisperer,

On your install, do you know how it affects a car with a tach? Does the tach still function? According to Pertronix, the PIII's need the full 12V, which means you can't just replace the pink wire and keep the tach functional.

Carl

whisperer · 11-07-2009, 02:28 PM

Carl, I don't but I would like to hear from someone that has worked out a problem with the factory tach when the Pertonix is wired correctly. Nothing is changed on the original wiring circuit to the coil, thru the tach or not. Maybe there is an issue with how the coil dumps and that is affecting tach signal, but on a I or II there is no Multi spark or anything. I would think the tach would see the same signal. I know that people have reported problems with the factory tach and Pertronix configuration before.
When the Pertonix is wired into the back side of the ignition switch it is just like installing any other accessory, stereo system, extra lights etc.. It's just taking a 12VDC power feed from the "ON" side of the switch.

ausmhly · 11-07-2009, 04:05 PM

Hi Herb,
Another reason to go with the Pertronix is that it will compensate for a worn dizzy shaft.
Pertronix requires a sports coil, with 40,000 volts for good performance.
Cheers,
Roger

herb65 · 11-09-2009, 11:39 AM

Guys;
Thank You all so much for the replies,sorry did not get back sooner been busy outside with the good weather. Whisperer,IT WORKS

tach,engine,everything.Did just what your web sight said,took a 12v switched source from under the hood that on the wire schematic says is for emmisions.Took it out on a Sunday cruise without a glitch and even saw the north side of 130 mph(oops, am I suppose to say that)If anyone has any questions let me know because this was a great fix that has plaged me for 15 years.I am still going to go to a 130 amp one wire alt just to keep things fully juiced.Herb