Pertronix or dual points?

[deathsled]

I had a problem in paradise with the Shelby.  Once again, when the engine warms up and heads toward hot, it can cut off and the revs die, then I coast to a viable spot to pull over.  When the engine cools down it starts up again.  The second to last time that happened, I replaced the module inside the Pertronix distributor.  I just finished up again replacing the module today and also replaced the coil that appeared to have some corrosion inside it. The distributor is now on its third module.  The technique for installing the module is reminiscent of my 89 Saleen Mustang that I owned a while ago but sold.  It would quit anywhere and at any speed without warning.  I think there was a TSB on the problem but never elevated to the level of a recall.  The TFI (thick film ignition) module slapped on the side of the distributor on the 89 Mustangs can go bad and then the new replacement needs some dielectric grease to help it work before it is bolted on.  It also had a stator in it.  (Not sure if dual point ignition has a stator but I will look it up.)  The Pertronix requires the same thing.  Dielectric grease then bolt the little thing down inside the distributor as opposed to the side as in the late 80s application, and button up the distributor once you put the rotor back on.  I did some research on YouTube regarding Pertronix issues and the comments sections were replete with commentary about how their engines would cut out while driving.  Same problem I had.  Seems to be gone now.  I fiddled with the distributor and turned it clockwise until it fired up then locked it down.  I have not thrown a timing gun on it but seems okay for the time being.  The consensus with a number of Pertronix guys was that they were done with Pertronix and went back to points.  I think I may be reaching a similar boiling "point."  I understand that Ford distributors that would be period correct are as rare as they are expensive.  Neither Autolite nor Motorcraft would be correct.  But then again, the engine is an 86 302 roller rocker engine donated to the car by my father.  It apparently came out of a drag car.  Runs pretty strong.  Go back to a dual points setup or deal with Petronix issues?  Am I exchanging one set of problems for a different set?  Which set of problems is more tolerable?  I hate driving with the sword of Damocles hanging over me that the engine could quit at any moment no matter where or when.  I understand points need tweaking or replacement every 5,000 miles but they can be serviced at the side of the road if they go bad.  Are points as risky while driving?  Is there some advance notice or inspection that can preempt such issues as quitting?

[Bob Gaines]

I had a problem in paradise with the Shelby.  Once again, when the engine warms up and heads toward hot, it can cut off and the revs die, then I coast to a viable spot to pull over.  When the engine cools down it starts up again.  The second to last time that happened, I replaced the module inside the Pertronix distributor.  I just finished up again replacing the module today and also replaced the coil that appeared to have some corrosion inside it. The distributor is now on its third module.  The technique for installing the module is reminiscent of my 89 Saleen Mustang that I owned a while ago but sold.  It would quit anywhere and at any speed without warning.  I think there was a TSB on the problem but never elevated to the level of a recall.  The TFI (thick film ignition) module slapped on the side of the distributor on the 89 Mustangs can go bad and then the new replacement needs some dielectric grease to help it work before it is bolted on.  It also had a stator in it.  (Not sure if dual point ignition has a stator but I will look it up.)  The Pertronix requires the same thing.  Dielectric grease then bolt the little thing down inside the distributor as opposed to the side as in the late 80s application, and button up the distributor once you put the rotor back on.  I did some research on YouTube regarding Pertronix issues and the comments sections were replete with commentary about how their engines would cut out while driving.  Same problem I had.  Seems to be gone now.  I fiddled with the distributor and turned it clockwise until it fired up then locked it down.  I have not thrown a timing gun on it but seems okay for the time being.  The consensus with a number of Pertronix guys was that they were done with Pertronix and went back to points.  I think I may be reaching a similar boiling "point."  I understand that Ford distributors that would be period correct are as rare as they are expensive.  Neither Autolite nor Motorcraft would be correct.  But then again, the engine is an 86 302 roller rocker engine donated to the car by my father.  It apparently came out of a drag car.  Runs pretty strong.  Go back to a dual points setup or deal with Petronix issues?  Am I exchanging one set of problems for a different set?  Which set of problems is more tolerable?  I hate driving with the sword of Damocles hanging over me that the engine could quit at any moment no matter where or when.  I understand points need tweaking or replacement every 5,000 miles but they can be serviced at the side of the road if they go bad.  Are points as risky while driving?  Is there some advance notice or inspection that can preempt such issues as quitting?

Answer this question first. Is your Pertronix powered at the coil or another place and if so where?

[S7MS427]

For my money, I think it is worth sticking with the Pertronix.  When I get back from the Ford show in Carlisle, I'll explain a sure-fire way to install the Pertronix that makes no modifications to the wiring in the car and still delivers a full 12 volts to the Pertronix module.

I've been using Pertronix for over 20 years on both my cars with no issues.

[J_Speegle]

I've tried Pertronix on a couple of my cars but have returned to the simple point system. Got tied of the car dying out on the side of the road once it warmed up - normally at about 9-15 miles from home. One never left the shop after restoration before I changed. On that one one time it would start then five minutes later it would. back and forth.

Your mileage may vary as you have certainly seen from others experience all over the web

[deathsled]

[/quote]Answer this question first. Is your Pertronix powered at the coil or another place and if so where?
[/quote]

It has a positive and a negative wire that connect to the little coil terminals and then there is an extra positive wire plug that goes over the little positive post on the coil after the positive and negative wires are attached.  For ignition perhaps?   Then there is the larger coil wire that goes to the distributor that has the same 8 mm thickness as a spark plug wires. 

[Cobrask8]

I had the same issue with my 69 SCJ. Was the coil. Under-cap conversion was fine. I swapped to a MSD coil, painted it black and put on the Ford Decal, Jacobs black 8mm wires, never a problem again. Better Spark.

If possible, do run the power for the module direct from a good  source, so not feeding through the resistor wire in the harness. Yes, an extra wire that is not stock looking, but your ignition system will be happier.

[FL SAAC]

We have run Petronix for years, no problems

Let me ask where is your ignition coil located?

Better yet, take a picture and post it in here. Cause my magic ball stopped working this morning.....

Thanks in advance and happy melt down day

[csxsfm]

No sudden failures with points.  Just routine maintenance.  I have a new Pertronix II and coil I've abandoned for that reason.  Where's Kranky on this?  I think he has an opinion.  LOL   

[shelbydoug]

There have been issues with the Petronix. There is no debate about that. Many have carried extra Petronix units with them.

Much of the issue is that the Petronix uses 12v to the coil and the Ford does not. The yellow top is a 6 volt system and measures 9v while cranking. It is powered off a resistance wire that runs directly from the ignition switch which reduces the 12v voltage to the coil by the time it gets there.


Ford ignition points are a simple system but you need to use the Ford yellow top coil along with the Ford resistance wire (pink) from the ignition switch.

One of the issues with the Ford system is that you can "burn out" the yellow top by leaving the ignition switch on with the engine not running.



I've run both the Ford points and the Petronix. The Petronix is more of a problem. It will exhibit these starting issues inexplicably at any time under any circumstances. I've also run the Ford pointless system and that is superior to either the points or the Petronix but it uses a separate "brain", control box, and as such looks different then the original vintage system.


One of the unspoken issues is that Ford distributors are driven by a gear that aligns to the drive gear on the camshaft. That is not an infallible system.

There are two items that can fail that will give you false signs of an ignition failure.

1) the balancer can slip. It is made in two parts. An inner and outer ring. They are held in place by being press fit and having an rubber sheet in between. The rubber ages, cracks and shrinks, the counter balance outer ring then moves by inertia to where it wants. Sometimes as much as 45°.

2) the distributor drive gear is held in place by a roll pin. The original Ford pins are very sturdy but on rebuilt distributors, care is not always taken to use a pin with the correct metal hardness. The inertia in the assembly can bend that pin and I have seen that change the timing 40 to 45°.


In these cases, you can pull a plug wire to test for it firing and see it fire, and yet the car will not start. Somehow the timing has slipped to where it is firing way off, yet the engine does not backfire. This is caused by one of the two "slipped" scenarios.


Also with either the Ford yellow top coil or the Petronix coil, if you leave the ignition on, walk away and forget about it, that will kill the coil. Positively. Dead. Morto bene.


Points themselves are not the culprit in any of these instances and the Petronix module will not save you from these pitfalls. I actually prefer the points. The Ford dual points have more tension to them then the single point and probably will need some attention at around 20,000 miles or so.


In the "old days" before solid state ignitions, I saved many a stranded car with locked up points. All you needed was a piece of sandpaper, a matchbook cover and a slotted screw driver, and you could be on your way in about 15 minutes. If the Petronix fails, you have to change it or get towed in.

Points are better for that reason alone.

[Bob Gaines]

Answer this question first. Is your Pertronix powered at the coil or another place and if so where?
[/quote]

It has a positive and a negative wire that connect to the little coil terminals and then there is an extra positive wire plug that goes over the little positive post on the coil after the positive and negative wires are attached.  For ignition perhaps?  Then there is the larger coil wire that goes to the distributor that has the same 8 mm thickness as a spark plug wires. 
[/quote] If you are getting power from the coil then your problem may be because the Pertronix is not getting a full 12 volts like the instructions says that is necessary for the module to work properly. The coil source is a cheater way of getting power for the module . It will work but since it is not a full 12 volts (9 1/2 volts I think when key is in on position through the resistor wire) can sometimes cause problems. To get a full 12 volts typically a wire is connected in the harness at the ignition switch shortly BEFORE it turns into resistor wire for the coil and run this extra wire out to the module for power. The problem you describe is a common problem with Pertronix and the change to full 12 volts like the the factory says the module requires is the common way to typically solve it. Another way to get 12 volts out to the module without running a extra wire is to eliminate or bypass the resistor wire in the harness to the coil but then you MUST run a after market coil that has a built in resistor . Most if not all aftermarket coils are made to run on a full 12 volts or the lower voltage of the resistor wire because they have a INTERNAL resistor so only the lower voltage amount gets to the coil windings. If you run a full 12 Volts to a Ford yellow top coil it will heat up to a point that you can't even touch it before failing or exploding!   I don't know how many times I have heard the Pertronix problem stories and getting power at the coil is a root cause on the vast majority. 

[Bob Gaines]

It is pretty simple to figure what wire to use at the ignition switch for full 12 volt power. There is a short wire with a bullet connector that comes off the ignition switch that your tach wire plugs into . You tap into the wire someplace between the ignition switch and the bullet connector and run that wire out to the pertronix. You are all about day 2 modifications so the extra wire should not offend your sensibilities. I would run a black wire so that it blends in more with the existing harness but that is just me. If you want to get creative you can tape wrap the extra wire into the harness at the firewall and let it exit out closer to the coil so that it is harder to distinguish as extra. Best of luck on how ever you decide to solve your problem.

[deathsled]

Wow, a lot for me to unpack and understand. School is in session. Thank you for the info. The coil was moved from the driver's side to the passenger side by my friend. I didn't know this was possible but he said it belonged on the passenger side of the engine block. I took a couple photos. I will check out the ignition wires as advised.

[FL SAAC]

Wow, a lot for me to unpack and understand. School is in session. Thank you for the info. The coil was moved from the driver's side to the passenger side by my friend. I didn't know this was possible but he said it belonged on the passenger side of the engine block. I tool a couple photos. I will check out the ignition wires as advised.

Good move on coil and keep it as far as possible from the heater hoses.


On the coil take the petronix sticker off.

 Then get model car paint, mix yellow with black until you get the color close to the original coils color. Paint the top.

Magic !

[Bob Gaines]

Wow, a lot for me to unpack and understand. School is in session. Thank you for the info. The coil was moved from the driver's side to the passenger side by my friend. I didn't know this was possible but he said it belonged on the passenger side of the engine block. I tool a couple photos. I will check out the ignition wires as advised.

Yes the coil was factory installed on the passenger side. Yes I can see that you are getting power from the coil terminal. I am familiar with your style coil and it has a internal resister so it can be used with the stock resistor wire that steps down the voltage to the coil or with a modified wiring with full 12 volts from the ignition switch bypassing the resister wire wrapped inside the stock wiring harness. The resister inside the aftermarket coil steps down the voltage inside before it gets to the windings. The problem is that if you have a stock wiring harness with the stock resistor wire wrapped inside then your aftermarket coil terminal is getting less then the full 12 volts and consequently since that is where you are getting power for the module is suppling less voltage then what the module needs to work properly. As has been said before sometimes the module will work properly at least for a while with the lower voltage and sometimes it will act up and stop running similar to the symptoms you describe.

[Bob Gaines]

Wow, a lot for me to unpack and understand. School is in session. Thank you for the info. The coil was moved from the driver's side to the passenger side by my friend. I didn't know this was possible but he said it belonged on the passenger side of the engine block. I tool a couple photos. I will check out the ignition wires as advised.

Good move on coil and keep it as far as possible from the heater hoses.


On the coil take the petronix sticker off.

 Then get model car paint, mix yellow with black until you get the color close to the original coils color. Paint the top.

Magic !

Unfortunately the coil in the picture is the much larger common Chevy style coil and is easily distinguished as different compared to the shorter shaped different Ford yellow top coil. It is not worth the time and effort to disguise it because it is so obviously different and it just comes off looking cheesy with a yellow looking top IMO. At least to those that know the difference.  The flamethrower EPOXY style coil from the same company on the other hand is the same size/length and shaped much similar to the Factory Ford coil. Rusto-oleum 250896 Satin Amber is almost a identical match to the proper yellow of the yellow top coil. All in all it will not be a exact replica ether but close enough that it will make those in the know take a second look.