Ignition question....my coil blew up today

Discussion in 'Sparky's corner' started by jaystoy, Apr 29, 2010.

  1. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The box steps up battery voltage, and stores it in big capacitors. At the proper time, it applies that to the coil to produce multiple sparks. The primary voltage is 450 -500 volts.

    http://www.ignitioninfo.com/cdignition.html

    In any case, we can agree to disagree:) :TU:
     
  2. tlivingd

    tlivingd BIG BLOCK, THE ANTI PRIUS

    a gm HEI setup.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I would run a CD ignition box like an MSD or Mallory. Use points to trigger it. They will last forever if all they do is trigger the box. The MSD 6AL is down around 200.00, cheaper on E Bay. I've heard a lot of good things about the Mallory boxes also.
     
  4. jaystoy

    jaystoy Well-Known Member

    Alright, well lets see what pertonix is going to do to rectify. Sucks, tired of not being able to just drive. One stupid problem after another.
     
  5. RAbarrett

    RAbarrett Well-Known Member

    Something to consider here guys is the possibility that the connection from the solenoid to the coil may have a problem. Here is how the system works. In the run position, the coil should see something like 9 volts. In the cranking position, the voltage from the battery drops due to the starter load. The full battery voltage, therefore, comes directly from the solenoid S terminal, and should be very close to battery voltage, maybe 1 volt less max. Here is the thing when testing. When using points, if the points are closed, the current through the battery may cause a voltage drop at the battery terminal. The voltage will rise and fall at the battery terminal with the points opening and closing. If the points stay closed with the engine not turning, the current through the coil can cause an explosion. If you are not using points, the voltage at the + terminal should be close to battery voltage at all times. There should be no ballast resistor, as its ONLY job is to limit current being switched by the points.
    With electronic ignition, especially aftermarket units, the box supplies voltage to the coil. When the engine is not turning, the voltage is essentially 12 volts, to prevent damage to the coil. When the engine is running, or turning over, the box supplies the full 450-550 volts to the coil.
    Herein lies the rub. If you are using a points coil with electronic ignition, it will likely either have a short life, or explode. It has to do with the internal resistance of the coil. Points ignition coils typically have slightly lower resistance in the primary or points side of the coil, to provide the maximum secondary voltage with the limitations of points. Electronic ignition coils typically have a slightly higher resistance in the primary, since the transistor is current sensitive, and the system typically uses full battery voltage. The coil, and the switching voltages must match, or you pay the piper.
     
  6. Sportwagon400

    Sportwagon400 Well-Known Member

    I agree to disagree :TU:
     
  7. jaystoy

    jaystoy Well-Known Member

    Ray, nice clear explanation, thanks. Here is a thought. This might be my fault.......maybe. Last time I ran the car, I put it back in garage and started doing a few things. Anyhow, went to have dinner, play with my son then put him to bed. Went back down to garage, realized I left the key in on position for like 2 hours. Did not start car, just shut it off and then started the car today and kaboom!! Couls leaving the key on, 12 volts to coil for 2 hours have heated it and cracked it, then me caranking it today made it blow?? Pertronix warranty will not want to hear this!! That was a pertronox coil.

    Also, just looked, the stock coil I bought today just to get car started said on it "12V External resistor required" I have no external resister anymore, so more than likely this coil will not last right? Damn car or...damn me! Pertonix is sending me a new module, maybe just get another flamethrower and not leave the key on.
     
  8. ceas350

    ceas350 "THE BURNER"

    .5 man you will save money in the long run. Your car will run the same:beer
     
  9. mjt

    mjt Well-Known Member

    YES! And that was my question to you in my original reply in
    your duplicate (original) post in another forum - in the future,
    ask the *admin* to move your post to another forum.

    In a distributor system, if you had 12v real-time to the coil and the
    points were open, you'd have anywhere from little to no amps, and
    if the points were closed, it could pull upwards of 15+ amps.

    So, guess what happens next :)

    Let's hope Pertronox doesn't patrol these boards, cause you just voided
    the warranty.
     
  10. 64SkyConvert

    64SkyConvert 1964 300 ci

    Disregard- I thought the installation was an Ignitor II.
     
    Last edited: Apr 30, 2010
  11. CameoInvicta

    CameoInvicta Well-Known Member

    Like mjt said, yes. It says right on the instructions for my Pertronix III to not just leave the key in the on position for any extended amount of time.
     
  12. RAbarrett

    RAbarrett Well-Known Member

    Just for grins, guys, you can go to any parts store and use any ballast resistor for any vehicle on yours, IF THE VEHICLE REQIURES ONE, AND DOES NOT HAVE ONE NOW. I put this in caps to prevent someone from installing one where one already exists. There are many occasions where an aftermarket ignition is retrofitted with the original points, and the external resistor is removed, for the aftermarket unit. When going back to points, it is necessary to use an external resistor. Back in the day, there were coils available that had the correct resistance wire in the coil, and no external resistor was necessary. Also, back in the day, though there were fewer available, there were aftermarket ignition boxes available to retrofit to a vehicle to improve the vehicle's performance, and these units required you to remove the resistors or to bypass them. It isnecessary, therefore, in the event that you are returning to points, to be sure that the resistor is again installed. If the vehicle had a V8, a V8 ballast can be installed in place of the resistance wire in GM's, or in place of the original resistor on Ford or Chrysler. Though the resistance varies slightly, manufacturer to manufacturer, it is within the manufacturer's tolerance. Points ignitions get either a resistance wire or an external resistor. These are all points getting lost in the translation as we harken back to the glory days, not being aware of the "stuff" we had to contend with back then. Still, it is COOL.
     
  13. 64SkyConvert

    64SkyConvert 1964 300 ci

    Well said- thanks for laying all that out.
     
  14. Ken Mild

    Ken Mild King of 18 Year Resto's

    I'd be interested to see what they say and find. Mine went bad and the car spit and sputtered past like 1/3 throttle. Got a NAPA coil with built in resistor and never had a problem since. Was ok cause I just ran my newly run 12v wire Why the hell can't they just make a reliable coil? They say to run 12v to it, I spend half a day bypassing the resistor wire and it lasts less that 1 season. They don't know how to make a coil handle 12V. Is there a better quality stock mount coil that can handle 12V??
     
  15. tlivingd

    tlivingd BIG BLOCK, THE ANTI PRIUS

    They probably make the coil live in 12V +- 10% . However many cars run closer to 14v due to the charging system. This is what happens when you outsource your engineering to a country where few people have a modern car and no vehicles to test their product on.

    Also this is why if you buy led switches and indicators for your car you want them specd closer to 14v.
     
  16. Ken Mild

    Ken Mild King of 18 Year Resto's

    Ok, agreed, but lots of guys use coils with no resistor. How do they keep them from blowing up or frying? You don't seem to hear this happening as much to any brand except Pertronix.
     
  17. idahoskylark

    idahoskylark idahoskylark

    ive had my ignitor 11 setup in for 2 yrs now and have put pertronix in many customer vehicle and have had no problems ask about any brand and youll get bad revues from someone heck everyone i know with a msd box has had them fry and i dont here people bad mouthing msd (but i didnt put one in my car either)
     
  18. jaystoy

    jaystoy Well-Known Member

    Wow, did I ever cause controversy!! LOL. Installed not Ignitor module, the blow also fried module. Installed new flamethrower coil. Car started Immediatley!! Very relieved.
     
  19. RAbarrett

    RAbarrett Well-Known Member

    There are several things controlling the total current through the coil primary. The first is the resistance of the primary winding. The higher it is, the less current flows, when it does. This results in a loss of ignition voltage, but also controls the heating of the coil.
    The second is the dwell time, or the amount of time the points stay closed. The longer they stay closed, the LONGER the current flows, again heating the coil.
    The third is the amount of voltage applied to the coil primary. As some ignitions apply over 400 volts, it becomes an issue of how much of the current is dissipated. The more that is dissipated, the cooler the coil stays. That is why many of the ignitions multi-spark at lower rpm, as fewer sparks per second tend to heat up the coil, as the energy builds.
    The size of the available spark is the result of two things: How fast the voltage in the primary builds, and how fast it disspates. We are constantly walking a tight-rope regarding what we have as opposed to what we can use.
    If you watch an electronic ignition dwell signal, the dwell rises as rpm drops, to provide amximum spark when needed, and as rpm rises spark frequency rises, and the dwell drops to control the current through the coil primary.
    One reason we now have one coil per cylinder is because the reduced spark frequency allows a higher available voltage, but the higher voltage is rough on coils.
     
  20. 69GSCAL

    69GSCAL Well-Known Member

    Five times! That's the magic number. Nobody will listen till you've said it Five times! You're almost there, don't give up.:TU:

    I ran the same set up you had in a 350 and it saw more than a few 12 hour trips. Only stopping to fill up for gas, that coil was getting hit with 12VDC for 3-4 hours without a break. However, it was being discharged for that time.

    Petronix does get a lot of hell on most message boards, but I've never had a problem with them. I guess I'm just one of those guys that insists on learning the hard way. :Dou:

    Very good info in the thread though! Rabberret's posts are priceless and I like the idea of running the half ohm resistor if it proves to keep the coil cool.
     

Share This Page