Pertronix Ign. versus Durasparks - Coil Q.

[james singleton]

I presently have a Pertonix l Ign. with a 1.5ohm coil. I recently bypassed the "pink" resistence wire, and was told on this forum that I may be putting the lower ohm (1.5) coil at risk now that I have bypassed the resistence wire. It would be easy for me just to re-install the resistence wire to protect the 1.5ohm coil, but since I might possibly be going with a Duraspark Ign system in the near future, can anyone make a recommendations on a coil (I assume a 3.0ohm coil) that will work both with my current Pertonix Ign. and later with a Duraspark Ign. set-up???? Should there be any difference between the two types of electronic ignition systems (Pertronix v Duraspark?. I do not want to have to buy a different coil if/when I switch over to the Duraspark Ign.; if not necessary! Thanks Jim

 

[rmoe88]

the pertronix website lists the 1.5ohm coil as being able to work at 12volts on 6 and 8 cylinder engines.

What type of coil can I use with the Ignitorâ„¢? How do I check my coils 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 cylinder engines should not exceed 4 amps. Six and eight cylinder engines should not exceed 8.5 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 8

Link

From what pertronix says, you should be fine with how you have it now. I just ordered the same coil and i am going to take out the resistor wire as well

 

[Bort62]

Well, I'm not sure how the # of cylinders has any effect on the heat disspating capability of the coil but -

The stock coil will die eventually if you run it without a ballast resistor. I am using an accel 12v coil that works fine. I don't know the PN off hand. I'm also not sure what it's primary resistance is off hand but I do know it was designed to run at 12 volts.

Any 12v coil will work with the ignition regardless if it is duraspark or pertronix.

 

[rmoe88]

I dont think they are referring to the ability of their coil to cool. I think they are saying their "ignitor" points-eliminator product should not deal with more that 8.5amps. Also, the primary in the pertronix coil is higher resistance than regular aftermarket coils (msd blaster coil is .7ohms), i think this is why they put up using 12volts as an example.

Using their math, an "msd blaster 2" at .7ohms and the stock 6volts will give 8.57 amps, the max that they recommend for their "ignitor". The pertronix coil "flamethrower" with 1.5ohms primary at 12volts (no resistor) will give 8 amps. So does that mean it is more reliable to use their coil without a resistor wire, than to use an msd coil with a resistor wire?

 

[60s Refugee]

I ran my petronics system with the flame thrower two coil with the pink wire in place. It worked fine. I am removing it in favor of a DSII more for the hell of it than anything else, but I did read a few threads that suggested there were a few people who had timing issues with petronics. Mustang Monthly magazine article on the subject says the petronics set automatically adjusts timing. I don't know about that. I had some operating/timing issues but now I realize it was two bent push rods that was causing my problems.

Harry

 

[james singleton]

Moe, thanks for posting that info from Pertronix's website. I believe it was off of their website that led me to install the 1.5ohm coil when I first installed the Pertronix Elect. Ign. a year or so ago. I did not feel like removing, or bypassing, the resistence wire at the time. Well recently I did bypass the resistence wire and I believe Ian/Bort62 had mentioned the possibility of the 1.5ohm coil going bad over time with the full 12 volt charge. Like Harry/60's Refugee said in his post about changing from the Pertronix to the Duraspark Ign. system, I was going to change just for the heck of it; hence the question(s) about the various coils (1.5ohm versus a 3.0ohm; and whether one coil will serve both electronic ign. set-ups). I have a couple of carbs, one is a SCV type which works with my L.O.M. dizzy, and I also have a "non" SCV type carb that I was going to use with the Duraspark set-up that I salvaged from the junkyard. I was going to try both set-ups and see which combination I like the best. I appreciate all of your input! Thanks, Jim

 

[kirkallen143]

I don't know the PN off hand. I'm also not sure what it's primary resistance is off hand but I do know it was designed to run at 12 volts.

IF it is yellow or chrome w/ a black top it is the 8140 super stock coil and is rated at 42000 volts and 1.4ohms. The brown top, breakerless coil is 45000 volts and I do not know its primary resistance rating.

Kirk

 

[MustangSix]

The Pertronix has a limited ability to handle current, hence the requirement for either a high impedance coil or a resistance in the voltage feed to the coil. It's a remarkably simple circuit that uses a Hall sensor and a switching transistor.

The resistance wire's original purpose was to limit current to the points to extend their life. If you retain the resistance wire, you still need to ensure a 12V feed to the Pertronix itself.

 

[ludwig]

Tap off the back of the switch BEFORE the pink wire. Run a separate wire to the dizz to fire the Ptrnx.