[t.mcginley.jr]

Hi all,

66 coupe, 289 4bbl, auto. Rebuilt engine has a few thousand miles on it, no issues whatsoever. A couple months ago I pulled it in the garage to do a bunch of work and now it won't start.

Details:
Has an Edelbrock 1406, 4 barrel carb
Pertronix billet distributor (electronic)
Pertronix flame thrower coil

It started no problem when I pulled it in the garage, then I installed an electric fuel pump and now I get no spark. I also replaced the starter solenoid in the process because I accidentally broke the old one. I didn't touch the distributor at all, the coil was sitting on the bench since day 1, timing wasn't touched.

The new electric fuel pump runs no problem, I get fuel to the carb and can see it squirting from the jets. I tried grounding a spark plug while cranking and am not getting spark. With the key in the "ON" position I get 12v to the solenoid I terminal. I also get 12v to the coil + AND - terminal. Is that normal? I have the red wire from the distributor and the wire from the ignition going to the + on the coil and the black dist. wire going to the - on the coil.

I thought the coil was bad because I was getting 12v on both terminals so I bought another one from Autozone and no change. What else should I test??

 

[Ivy66GT]

A Pertronix is just a transistor switch that simulates points; for either one the idea is to intermittently ground the - side of the coil. If your points (or Petronix) is not making a contact between the coil - terminal and ground then no coil current is flowing and you will measure 12V on both sides of the coil. You also will obviously get no sparks. It sounds as if your Pertronix is not working.

Did you have the ignition switch turned on for a few minutes without the engine running? That can kill a Pertronix I.

 

[t.mcginley.jr]

I can't remember exactly if that scenario has happened but it's possible. I'll have to look for instructions for the Pertronix distributor and see if there's a way to test the ignitor itself. Either way I shouldn't be getting any voltage at the - coil terminal correct?

 

[t.mcginley.jr]

Ok I did some testing with a multimeter. Both the Pertonix flame throw coil and the new Duralast coil ohm out at 1.5 between the terminals. I've installed both and neither will start the car.

First I hooked up the coil as per the Pertronix instructions:

With the key in the "ON" position I get 12v at the battery, at the "I" terminal on the solenoid, and on both the + and - terminals on the coil. So then I decided to run a jumper wire from the - coil terminal to the negative battery terminal (i.e. a new dedicated ground). Now with the key ON I get a little over 6 volts at the "I" solenoid terinal and at the + coil terminal, and nothing at the - coil terminal. Does that mean anything?

The distributor itself is grounded well, I check the housing itself against the battery + and get a solid 12v, and I checked the Ignitor itself's ground strap, same thing. I know that doesn't rule out a bad Ignitor, but it rules out bad grounding of the dist. itself. It's an Ignitor II by the way.

 

[Ivy66GT]

It probably means you have a bad Pertronix. With a Pertronix II having left the ignition switch ON without the engine running should not cause failure. However, your system could have died for some other reason. That is why you carry a set of points in the glovebox just-in-case.

There is probably nothing wrong with either coil; they are pretty much identical. Either your Pertronix is dead or you have a broken wire connecting it to the coil. I know of 4 Pertronix coils with 1.5 Ohm primaries: 40001, 40011, 40111 & 60115 Every one of them has the same 6.4 mHenry inductance which is less than the Ford coil which had 9.5 mH. (I.e. the Ford coil in good condition will give you a spark with a little more energy!) If you have the C819 coil from AutoZone its almost exactly the same as the Pertronix ones; 6.6 mH - it may even be the SAME coil coming in a different box.

Your jumper wire is doing what a closed set of points or your Pertronix should do; its grounding the - side of the coil. Your jumper is ensuring that the - side reads zero volts. There is a pink wire ballast resistor of just less than 1.5 Ohms between the ignition switch battery voltage and the + side of your coil. It needs to be there for any of those 1.5 Ohm coils with a Pertronix I or points; it doesn't have to be there for Pertronix II or III. (In or out, the ballast resistor is not your present problem.) With equal ballast and coil resistances you will see half of the battery voltage at the coil + terminal when you ground the - terminal. Your ballast is not quite 1.5 Ohms so you are seeing a little more than half battery voltage. The coil + is connected to the solenoid terminal so anything you measure in one place you should measure in the other.

If you have power to the coil, every time you disconnect that jumper wire you should get a spark from the coil. Try it and look for the spark. Its the same as if your points or the transistor switch in the Pertronix were opening.

Everything you report is as it should be up to and including the coil. The only thing bad is either the black wire going TO the Pertronix from the coil or the Pertronix itself. Put your points back in and the car should start with either coil.

 

[t.mcginley.jr]

Thanks for all the info Ivy, you sure know your stuff.

I just got done putting my original distributor in, which now I remember still doesn't have points. Someone at some point installed a Mallory Unilite electronic ignition. Either way it worked before I pulled it so I dropped it in, hooked it up to the "flame thrower" coil and it started right up. My ignition advance might be off because it doesn't run long, I'll have to check timing. But it does start now. This unit gets around 6.4v to the + coil terminal when in the ON position, and a little less than 1v at the negative side. So I think you're right, it's the Pertronix ignitor itself that's the problem.

 

[zray]

I've had 3 Pertronix fail. One was DOA right out of the box, one failed 100% when hot, the 3rd on had an intermittent miss. Others have been running them for years without any issues. I think it's quality control issue. You just can't expect consistency from a very inexpensive piece of electronics.

Z

 

[zray]

I've had 3 Pertronix fail. One was DOA right out of the box, one failed 100% when hot, the 3rd on had an intermittent miss. Others have been running them for years without any issues. I think it's quality control issue. One ust can't expect consistency from a very inexpensive piece of electronics.

Z

 

[t.mcginley.jr]

I've had 3 Pertronix fail. One was DOA right out of the box, one failed 100% when hot, the 3rd on had an intermittent miss. Others have been running them for years without any issues. I think it's quality control issue. One ust can't expect consistency from a very inexpensive piece of electronics.

Z

Inexpensive to make maybe, but a replacement Ignitor II is $110 from what I can tell (CJ Pony parts).

 

[t.mcginley.jr]

Also I found these instructions on how to test the Ignitor, I'm going to try it at some point this week to verify that it's bad.


1. Connect a jumper wire from the Ignitor Plate to battery ground.
2. Connect the Red wire from the Ignitor to the battery positive terminal along with the red lead from a volt meter.
3. Attach the Black wire form the Ignitor to the black lead of the voltmeter.
4. Move or rotate the magnet sleeve in front of the Ignitor Module, the voltmeter should vary from battery voltage to 0 volts and back.
5. If it does not, then you possibly have a burned out Power Transistor or a failed Hall cell.

 

[zray]

'

Inexpensive to make maybe, but a replacement Ignitor II is $110 from what I can tell (CJ Pony parts).

You are correct. I should've been more specific.

What I really was getting at, compared to other electronic ignition solutions, the Pertonix modules are inexpensive. You can expect to pay four times at much for any electronic product from MSD. Of course any company's electronic product can fail. But anecdotally speaking, I've had zero issues from my personal use of MSD products, or those I installed on customers cars vs. several Pertonix failures. Since I had to stand behind the shops work, I preferred to use components that I had more faith in. To repeat my other post, many folks have had no issues with the Pertonix modules and are understandedly satisfied.

I've come full circle with my thinking about classic car ignition systems. From '99 to 2012 I've personally used the best systems from MSD. However I've come around to advocating the use of the stock points and condensers unless there is a compelling reason that more adjustability is required.

I took advantage of some dyno time to compare the MSD, Pertronix, and the stock points system. The performance difference between all of them was slight. So slight as to not be detectable going down the road.

When folks are reporting better idle with the Pertronix vs. points I've found they are comparing worn out and dirty points with the new Pertronix. When the points are in good condition, there is essentially no difference in idle or anything else. On new cars running a very lean fuel mixture, perhaps a hotter spark is beneficial. But with these old carburetor cars, the points ignition has no problem providing all the spark needed.

Of course with the point ignition, the owner has to adjust them every 7,500 miles or so. For me that's 10 minutes every year and a half.

Z

 

[t.mcginley.jr]

Thanks zray, that's where I figured you were going when you mentioned the inexpensive part. Compared to other electronic ignition solutions the Pertronix is definitely on the cheaper end.

Back when I ordered the distributor itself I think I was so taken by the "billet aluminum housing" part that I just bought it regardless. Honestly I probably drive the car less than 1000 miles per year, so there's really no need to go with electronic ignition. If the ignitor in my Pertronix distributor really is shot, I wonder if I can drop a set of points and condenser in the nice billet housing?