Well, today I finally got around to changing out the Petronix unit that I installed around 8 years ago. Car has been running poorly for about a year. Crazy symptoms, felt like weak cylinder or two, stumble at higher RPM's, finally Flattening out at around 4K. Did a Comp. Test, new wires, Plugs, Cap/Rotor. No help. Finally started thinking the Holley was at fault but decided to change out the Petronix before looking at the Carb.. BINGO! Car runs like a champ again. I was of the Mindset that the Petronix would just Crap out if it was bad. Not So! I'm passing this Info along for General knowledge. Thanks for Listening! Al W.

 

Did you use the stock coil or one supplied by Pertronix?

From the design, I think a complete system will work.
But, using the stock coil, I think there may be a problem.

Tom Piper

 

Good call Tom! Yes, I did install the Pertronix Coil and wired it correctly. The new unit was a different design as it has a Ring with 8 little Magnets that Bolts under the Counter Weights. The old one was just a little Module. Thanks for your comments. Al W.

 

The reason I asked is because the stock ignition coil has about 6 volts , when the points are closed, across it because of the resistor in series with the primary of the coil.

When you use the Pertronix module in the distributor, the module drops about 1 volt more.
Therefore, you now only have about 5 volts across the coil primary when the Pertronix module is switched on.
What you have is:
1) 6 volts dropped across the resistor.
2) 1 volt dropped across the Pertronix ignition module when it is switched on.
3) That is 12 - 7 = 5 volts for the coil.
Therefore, you have less voltage across the ignition coil primary with the Pertronix.

By using the Pertronix ignition coil, it is designed to work with the voltage drop of the Pertronix module.

Tom Piper

 

Correct.

Here's something I developed a few years ago to help take the mystery out of the instructions that come with the Pertronix. This was specifically drawn for my 65. I'm working on a 62/earlier version with different wire colors.

 

I remember JohnZ telling us with an older design Pertronix unit you need to wait about 5 seconds before cranking for start. Anyone remember this and could you clarify this again? (You there John?). Thanks as always, Al W.

 

I'm not John, but yes, the early design Pertronix needed an energize period (for lack of a better term).

 

I just took out the old Pertronix and installed the II... reason being I installed a new gear reduction starter and with that there is no place to wire the ballast resistor soooooooo...time for the II which needed none...works and starts great

 

I installed my first PerTronix unit about 17yrs ago (on the 56 and it's still performing great). Since then, I've done about 50 (I personally have 4 engines with PerTronix conversions). Originally (before they offered their own FLAME THROWER coil), PerTronix recommended adding a HD oil filled coil. So, I started out with the MSD Blaster II until PerTronix introduced their own coil, then that's what I switched to.
Their original unit had the magnet ring (1181) and later they added the module that picked up off of the point cam (1181LSC). I prefer, and have stayed with, the original 1181 and have had ZERO problems (and no customer complaints) with it. Although, I must admit that the 1181 (with the magnet ring) is considerably more time consuming to install because it requires removal of the distributor for installing shims between the bottom of the dist housing and drive gear. Also, I have discovered that MOST Corvette tach drive distributors DO NOT have the huge gap at the drive gear that NON-tach drive distributors have (regular pass car distributors). With the magnet ring shimmed for a .010-.020 air gap between the ring and the top of the module, they work as advertised.
The PerTronix, and other similar electronic conversion units, IS NOT a super duper, double whamy fire breathing ignition system for hard core racing applications. But, it is an EXCELLENT conversion which eliminates the disadvantages of points/condenser, plus, it is entirely contained inside the cap with no external boxes to detract from the stock appearance. With their conversion unit and coil, they advertise up to 40,000volts. Maybe. But for sure, because of the inherent design, you're going to get more fire to the plugs than with points. And NO, the PerTronix coil (or any other aftermarket coil) does not look exactly like the stock Delco coil--------------------but with ignition shielding installed, no one can tell!

Tom Parsons

 

Thanks to all who responded. And Tom you gave me exactly what I was wondering about. For an old Shade Tree Guy like me, I find the retro stuff fascinating! Al W.

 

I have a first generation Pertronix with my stock ignition coil.
I put it on and shimmed the distributor gear and set the gap as required.
I had a low-speed miss that I could not get rid of, until I went back to points.
With an oscilloscope, I checked the voltage drop at the coil with and without the Pertronix -- both with the resistor in place.
The voltage drop across the coil is greater with the points.

Tom Piper

 

Where did you have the red power wire from the Pertronix module connected?

 

The ignition switch side of the resistor.

Tom Piper

 

Great info for future needs. I have the pertronix II and flamthrower coil. They work great!

 

This thread made up my mind about finally ordering the Pertronix unit. I ordered the 1183 unit for my 56, for some reason the mounting plate doesent seem to fit per the instructions, am I overlooking something?

 

Not sure what model that is, and how it compares to the ones I have, but on mine there is a little nub on the underside of the mounting plate which locates into a dimple on the points plate. You may have to remove a few screws in the point plate so that you can move the petronix around until it finds "home" and feels properly located.

 

I have it mounted and it is a nice fit....it is just backwards from instructions. Should the plate be towards the firewall, front of car, pass or drivers side. I did not notice any dimples but it lookes like it locates on the poins pin and the points cam, sort of like dowel pins.

 

Can you still buy the older version Pertronix?

 

Ecklers still sells them. I bought a "I" a few months ago

 

I don't think it matters, it's just a triggering mechanism.

Doh, I think I was getting it backwards. Points pin on the points plate, dimple in the pertronix probably. But then, I probably have a different unit. I run an Ignitor II in my 62 and 65.

What coil do you plan to run? I don't know about the Ignitor I, but the Ignitor II when used with the Pertronix Flamethrower coil, should be connected to bypass the ballast resistor.