Technical Pertronix III problems solved

Thought I should post something about my experience with the Pertronix III ignitor kit here, as it would have been really helpful if I was able to find more information early on.

I rebuilt my 1959 Cadillac 390 engine a couple of years ago and have travelled about 2000 miles since. Despite trying a number of different things, I have never been able to get it running like it should. It always sounded like it was running on 7.5 cylinders when driving it. I checked for bent pushrods or valves - they were fine. I removed the inlet manifold a number of times to re-seal it after being told that it had a leak.

The engine always started rich and took 5 or 10 minutes to clear itself properly. It has never idled smooth, and didn't seem to have the power I expected. I often thought I was being unrealistic in my expectations. I even had it dyno tuned and asked them to take a look - and they changed the spark plugs and said it was all good.

I started Googling a couple of months ago and found a two old posts in forums which talked about the problems with the Pertronix III ignitor. I installed a Pertronix I in my previous Cadillac and it worked a treat, so I thought I would give this engine the best available option and bought a Pertronix III and Flame Thrower coil. After reading the posts and reflecting on all of the things I had tried I realised that I had always assumed the ignition was good. One thing I noticed was the Pertronix III allowed the engine to crank for a second before starting the engine - this sounds good in theory however I suspetced this may have been the reason it always started like a pig.

I purchased an Ignitor I and a new coil, and 'downgraded' the ignition. I also took the opportunity to relocate the coil to the firewall where it would be cooler.

The first time I started the car it jumped into life immediately - it actually made me jump! No black smoke! No stumbling!

Having now driven it a couple of times, it has transformed the car. I now runs on 8 instead of 7.5 cylinders, and the idle is smoother. The engine runs like I always hoped, and as a bonus the throttle response seems a little sharper. I don't need to push the accelerator pedal as hard to keep up with the traffic. I wish I had tried this 2 years ago.

I hope I can help someone who may be having similar issues, and is about to tear their hair out like I was.

 

Maybe try installing points and it will really start running good? (Kidding!) Glad you got it sorted out.

 

Really good to see a how-I fixed-it story! Thanks.

 

So @Dimadee are you saying that III generation of that hardware is all defective? I am not sure what I am running but I so far believe all is well but geeze I am curious. There has been a fair bit of debate here and some of it not so good. I know leaving key on when engine is off may be a big no no.

 

I have only ever used II versions and had no issues. Long as you follow the instructions and use the recommended coil etc all seems to work well.
Saying this I always keep a set of points and condenser in the trunk with the kit to swap it out should something fail on a trip.

Yeah leaving the Key on the "On" mark will burn out the coil. fine to leave it on Acc.

 

My coil was matched to the unit and I believe I ordered it right from the company. I had a competent mechanic who bracket raced as a hobby install the unit. It really has been just a trouble free setup...knock on wood.

 

I guess what I am saying is the III has issues. Pertronix claim that the III adjusts the dwell angle to engine load and I read that it always cranks the engine for a period before starting. I wonder if they are trying to be a bit too smart? The slight miss when driving had me seriously wondering if I had lost the tip of a cam lobe. Turns out that it was the Pertronix module.

 

I don't think based on your description I am running this version but as eluded useful tech...glad it's ironed out for you. I guess warranty was not part of the stepping back a wee bit.

 

Points (and Pertronix I) will roast the coil after several minutes if the ignition switch is left in the RUN position without the engine running, if the points happen to be closed and current is flowing through the primary. There's usually no mention of this "feature" in the Operator's Manual or old shop manuals, which is kind of strange. Guess it was one of those "that oughtta learn ya" deals?

The Pertronix II and III have protection circuitry to guard against this, or so they say.

 

I thought the only difference between the II and III was a built in rev limiter that you had to set. Could this have been the problem? Just a thought.

 

I've personally never used any of the Pertronix products so I can't speak to their issues. I've always used the Crane Fireball XR-1 points eliminator and had good luck with them. They have a built-in rev-limiter (4-6-8) and the only time that I had a problem is when I inadvertently set it to 4,000rpm and attempted a 5-grand launch!.. Not really, but it would start "breaking down" if I tried to wind out first gear past 4,ooo rpms. Checked it out, realized what I had done (the little dial is quite tiny and a bit difficult for these old eyes to see) turned it to 6 and rectified the problem. Plus, they're a little cheaper (got mine from Summit) than any Pertronix version. No external box needed, but they do recommend using Crane's "matched" coil.

 

@hotroddon I'd like to hear your comments on this. Is there an inherent issue with the Version III modules?

I've got Pertronix Ignitor II modules in a couple vehicles and have had no issues. The reason we hear so much about failed Ignitors is that people who have issues are much more likely to complain than satisfied customers are likely to praise.

It's the same when someone has a bad customer service experience. They'll piss and moan about it to anyone who they think will listen. A good customer service experience is only occasionally preached to the choir.

 

Just as many threads praising them. Anything can go bad. I run them in four cars, two Chevy, a Ford and an MG. No failures so far and if you have the Pertronix distributor they all share the same module. So with one spare it's an easy fix if it fails. Definitely not traditional and I'm not knocking points but it works for me.

 

My experience all around was very good and the system has provided nothing but what it should be expected to do. It's one of the few modern additions to the vintage experience I have. I really appreciate that you would really never know it was there and if for whatever reason a breakdown occurred I have a service to deal with it. That is my story to date. 3 plus years approx 8000 miles

Stogy the Happy Camper

 

Did you contact the company?
If so, what did they say?
If not, why not?
I've been using their devices since 1990 without any problems

 

Don, do you know who owns Crane now? I knew it was taken over by S&S and picked up by some one else. I thought Comp Cams took over their cam division but not sure where the Ignition part went. This info could all be bogus, I don't know for sure. I did have great results using Crane stuff years ago.
Sorry for the detour. I hope the OP gets back for a little more detail.

 

Yeah, S&S Cycles took them over at one point. I'm not sure who now owns Crane or even S&S.

 

I ran a Pertonix I for over 15 years, worked great. It was the photo cell type pick up. During a much needed tune up I installed a type III. Nothing changed, just the Pertronix, then the problems. Timing was not consistent, engine would quit after running for 15 minutes. Called Pertronix and got their trouble shooting guy and guide, checked everything, even a different distributor, no help. Returned unit and put in a type I with magnetic pick up. All good, no issues for two years. Pertronix I is fine, maybe too much "gee whiz" in the III, I don't know. I just use what works and is reliable.

 

Just now I was looking into the 3 series for a Caddy. No finding but this is as far as I'm going with this other than to say. Counterclockwise rotation may have been a factor if a let's say Chevy clockwise unit was installed?

 

If I'm not mistaken the Pertronix (but not the P-III) can be run either with the resistor wire connected to the coil or also with a full 12 volts. Sounds like you initially had a first design Pertronox with a stock coil on a Caddy and it worked great, but on a different Cad you used a P-III with the Flame Thrower coil and noticed issues with the performance right away.
When a P-I was installed with a stock type coil on the second Cad (which can be wired with the resistor wire in place OR a full twelve volts) you had better results. The question is this-did you run the P-III with the resistor in place or with the recommended full 12 volts?

 

Do you have solid wire core plug wires? The original Ignitor can coexist with them, but the II and III cannot, and require that you use suppression or spiral-wound wires.

 

I had good luck with the one I installed in my Deuce pickup and never had a problem so I installed one in the Ranch Wagon and it worked great for a few years and it died in 5 o'clock rush hour traffic and I was at the light in the turn lane.

The module just quit,I reinstalled my old distributor and points and haven't looked back. HRP

 

The modules work really well but there's a whole lot more going on with good ignition than just the "switch" itself. Part of the problem is trying to achieve the dwell specification in a worn out distributor, is more or less impossible, so the points get ditched. Fair enough.

Usually though the worn out, loosey goosey distributor remains. Though a Pertronix Ignitor or other points replacement module itself is not affected much by distributor shaft wobble or endplay, the ignition and advance curve can still be sloppy and erratic, vacuum advance diaphragm shot, breaker plate sticky, etc. A fresh tight distributor setup correctly will perform like night and day whether using points or not.

 

interesting thread. I have a friend struggling with a Petronix in her 54 Ford. I will turn her on to this story. Thanx

 

Thanks for all the responses. I will answer them one by one....

Yes, I installed the P-III with a full 12 volts (same as the P-I in my previous Cad).

 

No solid core wires. I actually have a set or Pertronix wires.

 

I hope it can be of some help. When installing the Pertronix units I always made sure the earth and power wires were 100%.

 

OK, I see a theme here. Maybe the III is trying to be too clever?