A couple questions about ignition components:

1. what is the expected life of a distributor rotor?

2. is there any real advantage of a low impedance, high output (~40-45kV) coil in a stock motor?

The reason I ask is because I'm going to install a Pertronix ignitor in a stock 2L dizzy and trying to decide between Ignitor II or the new Ignitor III. The II has variable dwell and reverse polarity and over current protection so seems like a no-brainer over the original Ignitor. The III adds an electronic rev limiter and multi-spark. I'm doubtful the multi-spark offers any real improvement in a stock engine but the rev limiter is intriguing. I have a couple of stock rotors with mechanical rev limiter and like to use them, but the price difference in Ignitor models is way less than a replacement rev limiting rotor. Hence, my question about how long rotors last. Curious how often folks replace them.

Both Pertronix models can run low impedance, high output coils and I'm wondering if there would be any real improvement from upgrading. I have a box full of functioning OE coils so could spend my money elsewhere if a hotter spark won't make much difference on my boring stock motor.

Interested in your opinions.

The biggest difference that I noticed was quicker starts. IMHO, they’re worth it. As far as a Rev limiter; you’ll have about 15 seconds elapsed before you reach red line so I’d say, “Why?”

Funny guy. Are you saying quicker starts with just the Pertronix, with a hotter coil, or both? I guess I did read that multi-spark can help with cold starting so I guess that could be good too. Not that it ever gets cold here. Never seen it dip lower than -40F.

The Pertronix II has some other enhancements besides reverse polarity protection that make the original Pertronix obsolete. They don't make a III to fit my Mallory distributor or I would probably buy one.

I run a high output Pertronix II 45kv .6 ohm coil that is compatible with the Pertronix II ignitor. I also run NGK iridium plugs that are not popular here. The biggest difference is faster starts and in my opinion a more stable idle. To me it didn't make much sense to upgrade to electronic ignition without taking advantage of the ability to run a much hotter spark. I played around with a Mallory CD ignition but it cluttered up the engine bay with extra wiring for what I didn't think was worth the effort. The OE coil set up in my opinion is weak on purpose to work with breaker point ignition which is pretty ancient technology.

I think the stock rotor has a resistor built into it that may not work with a high energy ignition. My rotor is just a regular rotor and should last unless the contacts eventually degrade.

Fact is you have to use low impedance coils with pertronix,to get the best from it and possibly avoid any damage to the module,instructions state you must use a coil of 0.45ohms or greater for ignitor II,for Ignitor I the coil is a differant impedance don't remember off hand,I use their coils just to be sure.
They also state you cant use solid core leads with the II system,but these are less common these days anyway.
Absolutely no doubt there is better starting, found that out years ago when I fitted Ignitor I to my T2 camper which never started well with points with otherwise new ignition system.
Good luck.

This is good info. Thanks. I had not considered the resistor in the rotors but your right. Mine read 5k ohms and I'm assuming it's the same for the non rev limiting version. Aircooled.net sells a modified rotor with no resistance for ~$35 but the mod looks to be an easy DIY thing.

Have you had any problems with your tach playing nice with your setup? Sounds like sometimes a resistor needs to be added inline to the tach keep it happy.

I'm not seeing a downside to going with the Pertronix III, so that's what I'll get.

Thanks for the input guys.

I saw that. The Ignitor III can use 0.32 ohms or greater. I took that to mean the 3 ohm stock coils would be okay but you'd only be sending about 20,000 volts to the plugs. Their coils are reasonably priced. I just wanted to make sure there would be a real advantage with them. Faster starts is easily worth the price of admission in my book. It's been a long time since I had a running 914, but I seem to recall they tended to crank awhile before firing. In the winter, it was always a gamble whether it would catch before the battery gave out.

The pertronix II coil works fine with the tach. When I tried a Mallory CD box it required a tach adapter which I never bought because I decided to not run a CD box. I ran the Pertronix 3 ohm coil for a while but it's really no different than the stock coil. The Pertronix II .6 ohm coil made a big difference in cold starting and how fast the idle stabilized.

The stock distributor has a smaller cap than the Mallory cap and the leads are closer together. The closer leads may have a negative effect on the longevity of the cap and rotor. The 45kv coil may break down the cap and rotor at a faster rate. The fact that the oem rotor has a resistor in it and the oem coil is so weak may be by design partly because of the small cap. Thats speculation on my part.

Brett, I have the old style. No rev limiter and no voltage protection. My existing coil was a match and I assume it was stock. By cold start I meant first thing in the AM. Didn't matter if I was in SoCal or the CO mountains. Your results may vary but I doubt you'll ever regret installing that set.