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Ignition Coil Compatibility????

Discussion in '40- & 55-Series Tech' started by JJB77FJ40, Jul 13, 2005.

  1. JJB77FJ40

    JJB77FJ40

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    Are coils used in non Electronic ignitions (1977 FJ40 ballast resistore xternal ) the same as the coil used with ignitors and electronic ignitions (1987 FJ60).?

    Autozone lists the same coil for both years. However, SOR seems to list different part numbers.

    The coil that came with the FJ60 Dizzy from the auto salvage was tested to be dead so I tossed it(I should have saved for # comparison) and I have two other coils, one from a 1st generation 1976 FJ40 ignitor and the one that came off the 1977 FJ40. Can I use either of the two (both state use with External resistor)?

    Thanks,

    John
     
  2. Pin_Head

    Pin_Head

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    Yes, you can use them with the resistor.
     
  3. JJB77FJ40

    JJB77FJ40

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    Pin_head,

    So MUST I use the ballast resistor with the older coils? and w/the electronic ignition?

    or What if I don't use it ? might be the easier answer.

    I thought you didn't need it w/ Elec. Ignition?

    Thanks,

    John
     
  4. dfmorse

    dfmorse

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    John; You can use a resistance coil (resistor built in or external) with a reluctance distributor (no points in the distributor), but it is not necessary. The resistor is used in point type distributor/coil systems to limit the current thru the points when the engine is running (not starting).

    For example, in my 1979-80 FJ40 has really good reluctance (magnetic pulse) distributor that I removed and replaced with a MaFre Delco points distributor that drives a Jacobs electronic ignition. In this case, the points of the Delco trigger the electronic module to produce high voltage thru the Jacobs coil; no resistor in the primary coil circuit is required. The Advance curve of the Delco &/or Mallory points distributor was suppose to make the 2F engine run more efficient, especially at high altitude. And it does. There are lots of pros and cons on the subject. There is no argument that a Jacobs or DUI HEI system will improve the 2F engine.

    At the present time, I have (Delco) hooked up to drive the Jacobs coil without the resistor in the circuit; but this is strickly temp as the FJ40 is down for fender work (rust) and I'm building a new battery system. This works ok, but I will be using my Jacobs system or a rebuilt (19100-61101) original Toy distributor in the future.

    In summary; if the distributor has points, use a resistor in the circuit.
    If the dizzy is a reluctance type, no resistor is required.

    However, I am looking at my original schematic for the 1979-80 (USA and CAN) FJ40 and it shows a resistor/capacitor in the curcuit plus the ignitor (transistor), which is required for the reluctance distributor. I can find no resistor (external) on my cruiser or capacitor either. Is the schematic wrong? I'm still working on this confusion!

    Hope this helps a little...

    dfm
     
  5. Otterav

    Otterav

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    Hello,
    The resistor is used to step the normal operating voltage of 12 volts down to aprox 6 volts during normal engine running operation. The wire from the starter solonoid that goes to the coil hot terminal bypasses the resistor providing 12volts for starting(or close to it). If you use the external ballast resistor required coil without the resistor the coil will overheat and break down after a while. How do I know? My cruiser came with a external ballast required coil wired without the resistor wired in, after a while the coil would start missing and the cruiser would run poorly, as if the choke was pulled. Shortly after the coil died completely. Luckily the pertronix ign and coil had arrived that day! Lesson if it says external resistor required use it, but it will work on 12 volts for awhile.
    eric :grinpimp:
     
  6. JJB77FJ40

    JJB77FJ40

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    Thanks DFMorse. I followed some of that. I believe you are saying the electronic ignition can handle the high voltage of a non-resistored coil. However, a points system will fry (requires a max of 6 volts per Eric).

    Eric,

    I believe you answered both questions/concerns. If using the electronic ignition it can handle all the voltage(12) However, an external resistor coil is only rated for 6 volts resulting in only damage to the coil I presume.

    If the ballast resistor is used (reducing voltage to 6) w/ an electronic ignition will the performance be the same?(does not seem likely). It would seem that I need a coil rated for 12 volts ???

    With regard to Autozone calling for the same coil for the 87 FJ60 and 77 FJ40, is this because the coil is rated for 12 volts or is their ref. book screwed up?

    Thanks,

    John
     
  7. Otterav

    Otterav

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    John,
    Electronic, points it does not matter. The whole reason for the ballast resistor is to aid starting indirectly. The starter when cranking uses a tremendous amount of current, which causes the voltage to drop at the battery. In the old days starting was inproved by providing a higher voltage to the coil via the wire from the starting solonoid wire, effectively bypassing the resistor and supplying a high energy spark for the starting process. The resistor only reduces the voltage supplied to the coil, the electronic ignition only supplies a signal to the coil the same as points only more reliably. Most importantly if an aftermarket ign is used a specific coil may be specified, if not a 6volt with ballast or a 12 volt without ballast should be able to be used. You will note that the ballast is attached to the + side of the coil and the points /electronic ign is attached to the other terminal of the coil. Points will work with either 6, 12, 24 volts equally well, the potential difference is negligable electrically. Remeber the points/elect ign is only a switch. :beer:
     
  8. FJ40Jim

    FJ40Jim The Cruiser Whisperer SILVER Star

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    Yes, the 78-80 trucks have a resistor wire in the harness to drop voltage to the coil. It's a large diameter pink wire, says"Yazaki ignition resistor" or somethin on it. Slice open the engine bay harness and you'll find it.

    The 81-later systems use a single 12V wire to power the coil and ignitor.
     
  9. dfmorse

    dfmorse

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    "Yazaki ignition resistor"



    Thanks Jim; now I know what I'm looking for...

    dfm