Petronics

[jimTN]

I see Petronics 6V and12V conversions on epay. Anybody used the 6v pos gnd setup with success? Remember "Rumbleseat" comments from several years ago about repeated problems with the 6v conversions. Prices look good anyway.

[Butch11443]

The biggest problem with running the conversions is when you continue using a generator. The generator has voltage spikes which kill the Petronics unit. Alternator is ok.
Butch

[BUBBAS IGNITION]

The six volt positive ground unit is pretty tight on threshold voltage and the range with a generator is pretty up and down. We just don't use them anymore.
The 12 volt is a much more stable unit..

[Bruno]

Have a 6 volt Pertronix in my '52 F1 with their Flamethrower coil, also - LOVE them - been in for about 3-4 years and ol' Hennery runs great!! I'd recommend them for sure.

[Bruno]

Should have added that I have an alternator (1 wire setup).

[36tbird]

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Bubba, you mention the "threshold voltage". Yesterday when I went out for my weekly "exercise the flathead taco run", the flatmotor did not want to restart initially. After warm up, it always starts instantaneously. I checked the fuel pressure gauge to confirm I had that then checked the connections on my Bubba built Pertronix Chevy distributor. All seemed OK but it was if there was no fire. A passer by offered to check the spark while I cranked so we pulled #1. As soon as I hit the starter, she fired off. So, I'm trying to figure out what could be going on. The battery is about 3 years old and it was a pretty cool morning, if it is getting near the end of its life, could it have been short on that "threshold voltage" enough to not want to fire initially?

[BUBBAS IGNITION]

Originally Posted by 36tbird

Bubba, you mention the "threshold voltage". Yesterday when I went out for my weekly "exercise the flathead taco run", the flatmotor did not want to restart initially. After warm up, it always starts instantaneously. I checked the fuel pressure gauge to confirm I had that then checked the connections on my Bubba built Pertronix Chevy distributor. All seemed OK but it was if there was no fire. A passer by offered to check the spark while I cranked so we pulled #1. As soon as I hit the starter, she fired off. So, I'm trying to figure out what could be going on. The battery is about 3 years old and it was a pretty cool morning, if it is getting near the end of its life, could it have been short on that "threshold voltage" enough to not want to fire initially?

Any electronic controller ( module) is pretty touchy to battery voltage. We dont know the exact voltages to some but a typical factory chevrolet doesnt like to run below 9.6 volts ( 12 volt system) while cranking. Check the cranking voltage while cranking cold and see what it drops to ???

[kraken]

I ran a 6 volt Pos ground for about 2 years, and finally went back to points. When the engine was cold, it was hard to start. When it was warmed up, it fired and ran great. I called Pertronics, and the tech said the minimum voltage to fire the unit was about 4.5 volts. Sometimes I got 4.7 volts to the unit while cranking, and sometimes I got 4 volts. All electrical connections were cleaned before it was installed. The starter motor is an old unit, and may have been drawing too much to allow enough voltage to fire the Petronics.

[36tbird]

"Check the cranking voltage while cranking cold and see what it drops to ???"

Is this process as simple as putting a voltmeter in the line that goes to the Pertronix unit? I'm thinking I should disconnect the unit, take that wire and connect it to the + side of a voltmeter, - side to the frame and crank to see what registers as the starter turns. Of all the plans you've ever read, is this one?

[4dFord/SC]

Similar to Kraken, I ran a converted diver's helmet distributer with a 6v Pertronix unit and an alternator for nearly five years. Never had a problem with starting, but as others warned me would happen, it suddenly died without a whimper one (fortunately) sunny afternoon. Have since gone back to points, and frankly I think the car runs just as well. Also, reverting to the stock coil allowed installation of a vintage Sun tach. Remember, points will always get you home

[36tbird]

"reverting to the stock coil allowed installation of a vintage Sun tach."
I run a vintage Sun tach on my 12v, Pertronix distributor. The tach and its box has been re-worked by Williamson's so that might be something you want to research in the future if you want to switch back.

My plan for a back up is a spare dizzy with a Pertronix.

[richard rink]

Jim,

My experience with the 6 volt Pertronix is similar to that of Bruno, i.e., using the Flamethrower coil and an alternator. Installation was easy. I have also run the engine with a Mallory dual point, centrifugal advance distributor, which performed well. I don't know that there is any difference in performance with the Pertronix unit. Richard

[Bruno]

AND I have an Optima battery - 800 CCA - guess this might also help?

[Russ/40]

Experience is definitely mixed, and there are a lot of reasons for that. Different people use differing discipline when it comes to system contact integrity, starter condition, and generator conditions. When the best of care is used, failures are rare. Especially with the latest 6volt units, as the early ones from the Remund Ignitions days were a bit intolerant to voltage spikes. My '40 has been running a 6volt pos ground Pertronix from Remund since the early 90s. It has never failed me. But I realize anything solid state can fail, so I always carry a points distributor with me ready to go. I do drive my car long distances with tours of 1000 miles at times. I had verbal exchanges with Rumbleseat regarding his experiences with failures, and I could not explain his experiences. One thing for sure, when you get left dead on the road, you usually don't give these things a second chance.

[BUBBAS IGNITION]

Originally Posted by 36tbird

"Check the cranking voltage while cranking cold and see what it drops to ???"

Is this process as simple as putting a voltmeter in the line that goes to the Pertronix unit? I'm thinking I should disconnect the unit, take that wire and connect it to the + side of a voltmeter, - side to the frame and crank to see what registers as the starter turns. Of all the plans you've ever read, is this one?

Really a voltmeter at the battery terminal willusually work just fine.
Might want to compare the voltage at the battery and atthe positive side of the coil.??

I just repaired a no start PERTRONIXS for a customer and the positive lead was poorly crimped inside the connector?.?

[4dFord/SC]

Originally Posted by BUBBAS IGNITION

Really a voltmeter at the battery terminal willusually work just fine.
Might want to compare the voltage at the battery and atthe positive side of the coil.??

When I put a voltmeter on my battery with the alternator running, the readings jump all over the place.

Also, would not voltage readings on the positive side of the coil be distorted by the ballast resistor?

[36tbird]

No ballast resistor with the 12 v Pertronix. Also, just want to get the voltage reading while the starter is cranking, engine not running.

[jimTN]

Hello Bubba, how about a capaciter for the 6vposgnd unit to absorb the spikes?

[Karl Wolf]

Originally Posted by jimTN

Hello Bubba, how about a capaciter for the 6vposgnd unit to absorb the spikes?

How about a zenior diode for the spikes?
Karl

[4dFord/SC]

Originally Posted by 36tbird

No ballast resistor with the 12 v Pertronix. Also, just want to get the voltage reading while the starter is cranking, engine not running.

Ah yes. I'd forgotten that I'd bypassed the ballast resistor when I had my Pertronix.

As for measuring the alternator voltage, mine is a single wire application that doesn't really kick in until something like 1800 RPM, so I'm not sure that a reading taken while cranking would be useful. But maybe I'm missing something.