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Ignition Issues-what Coil?

Discussion in 'Early CJ5 and CJ6 Tech' started by Jonbbrew, Apr 20, 2020.

  1. Jonbbrew

    Jonbbrew Member

    I am finally trying to fire up my 198 after doing work on it on an off for several years. The electrical things i have changed or played with is....Change to 10SI alternator, ignition key, some other wiring and battery connection improvements. I think i have the wiring right, but not wondering if my Coil, points or condenser is bad.

    If i do need to get a coil i know i probably shouldn't pick one for the original Buick standards since i have a internal regulator alternator now. What coil should i buy? Does the alternator change even impact the coil choice at all? I am thinking not.
     
    Last edited: Apr 20, 2020
  2. Keys5a

    Keys5a Sponsor

    The alternator should have no bearing on what coil to use. The choice of coil will be one with internal resistor, or not. This will be determined by the wiring to the coil. Do you have an external resistor, on the wire itself could be resistor wire?
    -Donny
     
  3. Jonbbrew

    Jonbbrew Member

    no just straight wire, nothing special. Still trying to also look for a good diagram, as maybe i missed reconnecting something.
     
  4. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Factory wiring or something else? Does it start and run with the coil you have? JMO - I would buy a conventional coil and use a ballast resistor.

    Standard UC12 or UC12X will fit in your coil bracket, and has no internal resistor. https://www.summitracing.com/parts/smp-uc12x?rrec=true
    A ballast resistor like this will work: More Information for WVE 6R1002 Back at the parts counter, we'd typically pick a ballast resistor from a '70s Dodge if the customer wanted a generic ballast resistor.
     
  5. Jonbbrew

    Jonbbrew Member

    Not yet I haven’t been able to make spark. Been researching ways to by pass the points to check coil.

    Because I know virtually nothing about ignition systems....what’s the advantage/disadvantage between both setups?
    Is there a wiring diagram so I can understand?
     
  6. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Which two setups? With or without ballast resistor? They are the same electrically. One puts the resistor inside the coil, the other puts it outside.

    I'm sure a CJ-5 wiring diagram has been posted here at some time. Do you own the FSM?

    Not anxious to curate your electrical education. There are dozens of pages and videos available online. If you can't find enough explanation online, maybe you could buy a book on automobile electric systems and read up. I'm sure there are plenty of used copies of such books on Amazon or Alibris or wherever. Or check the public library.
     
    Last edited: Apr 21, 2020
  7. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    One basic introduction to old cars you might try is an old Motors Manual. https://www.amazon.com/Motors-Auto-Repair-Manual-MOTOR/dp/B000BJ0GMW
    These books were meant (I presume) to help gas station mechanics work on lots of different makes of cars. If my 1954 copy is typical, the first third is general information applicable to all or many makes. The last part covers each make in general detail; focusing on tune-up, engine repairs and service specs. Covers passenger cars, not Jeeps.
     
  8. Jonbbrew

    Jonbbrew Member

    Thank you. I’m not expected you to teach me I was just looking for further clarification on what you provided. I can definitely search and have.
    My engine is not a CJ5 So searching that route is useless. So now I need to find out if my Buick engine came with a external resistor or if an internal coil version can be substituted as I and so many others have done with upgrading to a 10si alternator to get rid of external voltage regulators.
     
  9. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Well ... I think that's somewhat mistaken. The technology is quite generic, especially in this age. I'll ask again ... what wiring do you have now? One engine or another, doesn't make much difference. In this era, they connect to the chassis with the same few wires.
     
  10. Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

    wiring diagram with resistor wire to coil . now not to get you confused
    I would just buy a coil with internal resistor . and not worry about a coil with external ballast
    wiring from a old chilton manual
    CAM00812.jpg
     
  11. FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    to reiterate what Donny said...please do not confuse the coil/ballast resistor with the internal vs external alternator discussion. They are independent...I've run my 225 in most configurations as things have been upgraded a piece at a time and 10SI is completely compatible with either an internal or external coil resistor. The engine will run without any coil resistor, but it will eventually damage your points. You can just skip the resistor concerns for a bit in till you get it to fire. Add it in later.

    Make a diagram of your wiring and post...it will help us troubleshooting or double checking. Also, if you haven't, suggest cleaning points and checking gap.
     
    Glenn likes this.
  12. Jonbbrew

    Jonbbrew Member

    Hello,

    Still trying to problem solve my lack of spark. It has been years since i originally tore out some old wiring as i upgraded items and cleaned out some old wiring etc. I have two questions as my engine is a 198 but i also do want to upgrade systems, like i have done with the alternator so just looking at what the original parts are wont work for me.

    Question #1-Is there really supposed to be a wire from the starter to the coil so that the positive side of the coil has two connections? Is this mandatory for it to spark and run or just extra help or?

    Question #2-Just like streamling and upgrading the alternator to internal regulator so i could clean up some engine bay wiring and extras, i want to have an internal resistor coil. Since i assume that was not original equipment, which coil should i get and/or how would i go about determining that? I know not all things are interchangeable jeep ignition WiringDiagram-1.jpg with at 225 but was considering just using that engine to select.

    Thanks all.
     
  13. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Usually the second connection is for starting only. When the engine is running, the ballast resistor limits current / drops voltage through the coil. You can run for a while without the ballast resistor (hot-wired) but too long like this will shorten the life of the points and maybe overheat the coil (?) When starting, the connection direct to the battery bypasses the ballast resistor and juices up the spark for easy starting. Some sources say this is needed because heavy current drain of starting lowers the battery voltage, requiring a special direct connection when cranking. Or maybe the hotter spark simply helps starting.

    Thre are two styles of these coils; with an internal resistor and without. The extra starting circuit does nothing if the resistor is internal to the coil. You need to be able to separate the coil from the ballast resistor to take advantage of the "extra juice when cranking" feature. When running, both style coils are electrically the same, except the ballast resistor heat will be inside or outside the coil can.
     
  14. Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    This feature is dependent on which ignition switch you are using. If your switch does NOT supply power to the ignition post and acc post during start position then you will need the "extra starting circuit" which is the wire from the starter "R" terminal to the "+" coil terminal.
     
  15. Jonbbrew

    Jonbbrew Member

    So what is the advantage/disadvantage of using an external resistor instead of internal in the coil?

    My wiring is replaced and correct it appears, with the exception of the starter to coil wire but still not spark. I am just considering replacing everything, coil, points, condenser, cap and rotor and just figure one of those is the issue.
     
  16. boopiejones

    boopiejones I can’t drive 55

    I would add the missing starter to coil wire and see what happens. I think your key is likely not supplying any power to the IGN post while the engine is cranking. so you need that extra wire otherwise you get no spark at startup.
     
    FinoCJ likes this.
  17. Jonbbrew

    Jonbbrew Member

    None. I was thinking of doing that first, but i just couldn't imagine that would really do anything. Especially with the new knowledge of if i am already using an internal resistor coil it wont make a difference as all the power is resisted already.
     
  18. boopiejones

    boopiejones I can’t drive 55

    i edited my post after you quoted it. I think the issue is that, because you don’t have the wire going from the starter to the coil, you’re getting zero spark at startup. Slightly resisted spark would be OK, but obviously zero spark is not ok.

    also, I’m not sure how an internal resistor coil works. It likely bypasses the resistor on startup so, just like the external resistor wiring, you’re still getting full voltage at startup. But either way you absolutely need the wire from the starter to the coil if your IGN post is not powered during startup.
     
    Last edited: May 31, 2020
  19. Glenn

    Glenn Kinda grumpy old man Staff Member

    Where are you checking for spark at? And how are you checking for spark?
     
  20. FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    As Walt and Jones said...could be your ignition requires the Starter wire...the one on my cj does. I went with an internally resisted coil when I installed pertronix, but still had to route the starter wire in to the coil. As you say, could have a bad condensor or coil as well....points need to be clean and gapped correctly (dwell)....
     
    Glenn likes this.