My COIL EXPLODED

[Bored&Stroked]

The 40001 coil is designed for a 12V application and - and is a 1.5 Ohm coil. The instructions for the coil say that you should have a direct 12V feed to it - and you should NOT have an in-line resistor installed. (They talk about bypassing the resister if the car has one). So, I'd do exactly as they say . . .

[19Fordy]

40cpe:
Does that mean that it is better to run a 3 ohm primary resistance rather than a 1.5 ohm resistance coil?

[JayChicago]

I would think the first question the Petronix tech would ask is: is your car 6 volt or 12 volt? I would think that must make a difference.

[Tim Ayers]

Originally Posted by Bored&Stroked

The 40001 coil is designed for a 12V application and - and is a 1.5 Ohm coil. The instructions for the coil say that you should have a direct 12V feed to it - and you should NOT have an in-line resistor installed. (They talk about bypassing the resister if the car has one). So, I'd do exactly as they say . . .

This is what I recall the instructions saying as well.

[V8COOPMAN]

Originally Posted by Lawson Cox

Go back to stock and get a Skip Haney coil. My 2¢

It is clearly evident, as shown in 19Fordy's enclosed picture, that he is running an 8BA-type engine, ALL of which use the more modern, upright distributors. Even more applicable to this thread, it is also easy to see that these ignition systems use a can-type coil which is mounted adjacent to the distributor, which is the STOCK location for an 8BA engine. SKIP HANEY does not rebuild the 8BA-type coils. Your 2¢ not good today. Coop

[glennpm]

Sponsored Links (Register now to hide all advertisements)

Hi Jim,

From Petronix http://www.pertronix.com.au/troubleshooting.html#ts5


"What type of coil can I use with the Ignitor? How do I check my coil's resistance? (12V negative ground only)

To determine if your systems coil is compatible with the Ignitor, some measurements should be taken prior to installation of the Ignitor. Caution… While performing this test, never leave the ignition switch on for more than 30 seconds at a time.


Set your voltmeter to a 15 or 20-volt scale. Attach an 18 or 20 AWG jumper wire from the negative coil terminal to an engine ground. Attach positive (red) lead of your voltmeter to the positive side of the coil, and the negative (black) lead to an engine ground. Turn the ignition switch to the run position. Now read the voltage at the positive coil terminal. Turn the ignition switch off. If the voltage measured is approximately 12 volts, no resistance wire is present. A typical resistance wire will provide 9 - 6 volts.


The next step is to determine the resistance in the primary ignition. Label the wires attached to the coil terminals and note their appropriate location. Make sure that the ignition switch is off and disconnect all wires from the coil. Adjust your meter to the lowest ohm scale. If you are using an analog style meter make sure to zero the needle.


Measure from the negative terminal to the positive terminal. Write your measurement down.


Now the maximum system amperage can be determined. Divide your voltage measurement by your coil resistance measurement. This will give you the system current or amperage.


Four and six cylinder engines should not exceed 4 amps. Eight cylinder engines should not exceed 8 amps. If the total amperage in your system is higher than the amount recommended for your application, you should install a ballast resistor.


Example: Voltage 12
Resistance 1.5
12 / 1.5 = 8
Total amperage is 8"


If you increase the resistance to 3 ohms, the amperage will be 4 instead of 8. I have no idea how much of a temperature difference that would make.


Glenn

[35fordtn]

Run a 3.0 Ohm coil. It's safer on your petronix uni, will produce less heat. Epoxy filled coil will be best.

[drolston]

Originally Posted by tubman

Bosch Blue Coil?

Ditto on Bosch Blue. Probably a fluke that the Pertronix coil failed. They are a good product but overkill for a flathead.

[Lawson Cox]

Originally Posted by V8COOPMAN

It is clearly evident, as shown in 19Fordy's enclosed picture, that he is running an 8BA-type engine, ALL of which use the more modern, upright distributors. Even more applicable to this thread, it is also easy to see that these ignition systems use a can-type coil which is mounted adjacent to the distributor, which is the STOCK location for an 8BA engine. SKIP HANEY does not rebuild the 8BA-type coils. Your 2¢ not good today. Coop

I can't be right ALL the time Coop. LOL

[ford38v8]

Originally Posted by Lawson Cox

I can't be right ALL the time Coop. LOL

Lawson, my wife bought me a coffee cup she said would fit me just fine. Emblazoned on it in big letters: MR. RIGHT.

[Tim Ayers]

Originally Posted by 35fordtn

Run a 3.0 Ohm coil. It's safer on your petronix uni, will produce less heat. Epoxy filled coil will be best.

Curious why you suggest this? All of the info in the directions from Petronix says use a 1.5 ohm coil.

Not arguing, just really curious.

[40cpe]

Originally Posted by 19Fordy

40cpe:
Does that mean that it is better to run a 3 ohm primary resistance rather than a 1.5 ohm resistance coil?

I don't know how much resistance it will take to affect low end or idle performance. I'd be more inclined to try a lower resistance such as an early v8 resistor with the 1.5 ohm coil, but it is trial and error. The point is that MORE resistance won't harm the pertronix per my conversation with the tech. Some of the higher end Pertronix will take a coil with something like .4 ohm (IIRC).

[flathead4rd]

I had the same experience you did. Top of coil forced off and oil all over. Cause, I left the key on while the car was parked. Bought a new Bosh blue coil with internal resistor and problem solved. Yes, I'm running 12 volt system.

[35fordtn]

Originally Posted by Tim Ayers

Curious why you suggest this? All of the info in the directions from Petronix says use a 1.5 ohm coil.

Not arguing, just really curious.

A flathead is not a super high compression, high spark energy using engine. Higher resistance is safer on the Petronix and Stromberg electronic ignitions. Unless you run a extrmeme rotor and plug gap this will be just fine. I run a 3.3 ohm coil on customer cars without a inline resistor that have electronic distributors and have never had a issue. (personally I run points)

[Ggmac]

Is there any chance your alternator/generator is overcharging? Possibly a bad regulator . I just checked a new one wire alternator and it was putting out 16.2 volts ! Ouch , replaced with a known to be good regulator and all is well . Its ashame new no longer means good .

[rotorwrench]

Coils of different primary Ohms are designed to work with certain voltages for reliability. Some folks have no idea how an induction coil works let alone what resistance works with what. When Ford developed the model A it was the first big step away from multiple trembler coils like the model T used. The model A used 1.5 Ohm can type coil and no ballast was needed on 6-volts. The V8 introduction changed the whole design of the ignition system. Marion Mallory helped Ford develope his front mounted set up. The coils were unique in design and used a short odd shaped coil core which also changed the primary and secondary coil windings. I'm not sure if they were 1.5 Ohm but I do know that they had to use a 0.8 Ohm ballast to insure they would run cool. Ford used variations of this set up till 1949 when they went back to the can type coil. No ballast was necessary with the 1.5 Ohm coil till 1956 when they changed to 12-volts. The change required a 1.3 to 1.5 Ohm ballast. Ford, GM, & Chrysler all used a ballast with a 1.5 Ohm coil.

Years went by and ballast resistors changed to ballast wires. Eventually, coils changed to 3.0 Ohm to work with no ballast. Modern materials like epoxy replaced oil and tar for internal insulation so the new coils could take the heat. It sounds to me like Pertronics is either not explaining thing well or they want to sell a lot of coils. A 1.5 Ohm coil will run too hot on 12-volts with no ballast. They expect the installer to insure the vehicle has a ballast wire or resistor without explaining that very well.

There is also the possibility that their coils are not very good quality. There should be no reason to run an oil filled coil in this day and age. All an electronic ignition system does is provide an electronic form of pulsating DC power to make the coil function. It takes half wave DC or full wave AC to step up voltage with any induction coil otherwise they don't work.

[Brian]

The above theory is correct...however, I ran my 35 V8 for years on 6 volt, using some sort of unmarked coil brought in from America. It has a black body and a gold sort of coloured top. Years later, when I converted that vehicle to 12 jolts, I kept the same coil, same configuration, no ballast resister [just as I used it with 6 volt], and it has run flawlessly like that for years.
Some years ago I imported a 1951 8N tractor. It too was 6 volt with the same sort of coil [black body/ gold top] When the 6 volt battery expired, I replaced it with a 12 volt battery, again leaving the coil unchanged. It too has proven trouble free.
Now, I don't know the coil resistance, however, I understand these are 6 volt coils. They run perfectly fine on 6 or 12 volts.

[flatjack9]

They sound like Ford coils.

[Brian]

I dunno...no markings, but they are good coils

[19Fordy]

THANK YOU to all who pitched in with responses to my question. I printed it all out. Will keep working on the problem and post results.

Thanks, JIM