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A-team Performance Oddfire Hei

Discussion in 'Early CJ5 and CJ6 Tech' started by Norcal69, Aug 12, 2020.

  1. Aug 12, 2020
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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  2. Aug 12, 2020
    47v6

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    Im sure they are china brand. I bet they will work fine, just make sure you get a spare Buick control module and some heat sink paste when you encounter a no start.
     
  3. Aug 12, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Is the module unique to the Buick? I would be surprised. You can use CPU coupling compound - get something with a high metallic oxide content, specifically made for coupling to heat sinks.
     
  4. Aug 12, 2020
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    This is what I was going to ask you. I think the module is the same as a chevy..... but is the module specific for the odd fire?

    Edit.... the module looks like it lists for a variety of makes.
     
    Last edited: Aug 12, 2020
  5. Aug 12, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Yeah, it's a detector circuit and big transistor switch - nothing odd or even about it. The firing angle comes from the passive part of the distributor (reluctor and pickup coil). I'm running a module from a Chevy in my CJ-6 (Standard LX-301), and it says it covers '77 231 Buick too.
     
  6. Aug 13, 2020
    47v6

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    When I had a problem with my HEI giving me a cold yellow spark I did an internet search about GM ignition control modules. At that time I got part numbers that were different for Chevy Pontiac and Buick modules from NAPA. The coils are different for buick too.
     
  7. Aug 13, 2020
    Brandon DeFord

    Brandon DeFord New Member 2022 Sponsor

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    I purchased this product to give it a try. However, my 225 is on the stand right now so I haven't had a chance to try it yet.
     
  8. Aug 18, 2020
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

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    I read on one of the Buick forums that the cheap Chinese dizzys can have a bad pitch ground into the drive gear. They can ruin your cam in no time.
    Going cheap on parts like this just isn't good economy, IMO.
    However, if you go with this, please report back on it's durability and performance.
    It's always good to have a trail spare.
     
  9. Aug 18, 2020
    Walt Couch

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

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    Would really like to see a picture of the inside of this red cap? Any chance?
     
  10. Aug 18, 2020
    Gaffer

    Gaffer New Member

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    The polarity of the coil is for sure different. I noticed this on my commando when I did the HEI swap.

    HEI's EXPOSED
     
  11. Aug 18, 2020
    cj6/442

    cj6/442 Sponsor

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    How much is one from DUI now? I have thier module in mine .....I felt a difference
     
  12. Aug 18, 2020
    cayenne

    cayenne Member

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    Do you think that 1" taller DUI distributor would help with the heat by allowing some more room for air to go under? I fry one every summer on my CRT HEI regardless of module brand and I am very careful with the thermal goop.
     
  13. Aug 18, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    What kind of coil are you running? The module must sink whatever current the coil sends to it, and this makes heat. Increasing the resistance of your coil will reduce the current to the module. You could instead run a ballast resistor between the switch and the coil, theough that seems like an inefficient approach. The higher resistance coil should have higher turns ratio, making a higher voltage spark.

    If I wanted to keep running the HEI style coil, I would remove the coil and measure the resistance, and then compare with other brands like Standard or MSD. Suspect that an MSD replacement coil is going to have a higher primary resistance and be easier on your module.
     
    Last edited: Aug 18, 2020
  14. Aug 18, 2020
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Tim,
    Do you have any knowlege of the reversed polarity? The coil that I installed in my new oddfire HEI came with terminals that were not bent for the slot on the cap. I thought nothing of it and bent them in the configuration that best fit my chevy small block knowlege. Maybe this was wrong? Ill go snap a pic with the coil cover off.
     
  15. Aug 18, 2020
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Reading online it looks like this is the standard configuration for a Chevy engine. Buick distributor would rotate the opposite way..... I think...



    F7B09E49-EBDD-4650-B6EA-5A5C4085493C.jpeg
     
  16. Aug 18, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    A passive component like a coil in principle will not be polar. In a traditional automotive coil, you are forced to connect it in a polar way, because the primary and secondary windings are connected together at the (-) terminal. This leaves you with three connections (+), (-) and the spark lead which you are not allowed to mix up.

    [​IMG]

    I see two wires plus a ground on the HEI coil, in addition to the contact on top, and I'm not sure how it's supposed to be connected. With the coil in the diagram above, if you did not know which terminal was (+) or (-), you could determine it by measuring the resistance between the spark lead (one end of the secondary) and each primary terminal. The primary resistance is pretty low, but you can (inaccurately) measure it. Measuring from the spark lead to (-) is just the secondary resistance, and (+) is the primary plus the secondary resistance.

    I would apply my multimeter and map it out.

    Sorry if this is just more confusing. I will look around to see if the HEI coil is better described somewhere. Looking at descriptions of HEI modules, your yellow and red wires should be isolated from the ground, and then connect to ground at the C tab of the module. The black wire is probably the ground of the secondary. If this is correct, there should be no significant difference in connecting red and yellow to the left and right, or connecting yellow and red. Isn't the metal tab shape on the end of each wire specific to a location in the cap? If that's true, then the coil manufacturer can use whatever color wire they want, and let the position be determined by the wire routing and the tab shape.
     
    Last edited: Aug 18, 2020
  17. Aug 18, 2020
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Tim,
    Does the info in this thread make sense to you?
    The tabs for power/ tach were not pre bent on the coil.
    Hei
     
  18. Aug 18, 2020
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Another fly to the soup.......
    Taken from Ignition coil differences | GBodyForum - '78-'88 General Motors A/G-Body Community

    "There are three different ignition coils and three different pickup coils."

    "Two of the pickup coils have opposite magnetic polarity and are to be used with the ignition coils of the same magnetic polarity."

    "Opposite magnetic polarity pickup coils are needed because of the underhood relationship of the distributor location to the starter and battery cable. During starting, magnetic fields are created. The pickup coil can be affected by these magnetic fields and give false turn-on and fire signals to the module causing engine misfire. By using a pickup coil of proper magnetic polarity, the external magnetic fields will not affect the pickup coil in such a way as to give false turn-on or fire signal to the module."

    "The third pickup coil has the same polarity as one of the other coils, but it has longer leads which are necessary in its application. Pickup coils can either be identified by the color of the plastic tie around the leads or by the color of the plastic connector at the end of the leads."

    Blue Tie or black connector Body
    1876210 (V-8) Olds (except Toronado), Buick
    1891209 (V-6)
    1880020 (L-4)

    Yellow Tie or Yellow Connector Body
    1875981 (V-8) Chevrolet, Cadillac, Olds Toronado
    1880040 (L-6)
    1892175 (L-4)

    Clear Tie or Clear Connector Body
    1876495 (V-8) Pontiac

    Yellow connector
    1894237 (V-6 200 CID)

    Black Connector
    1893894 (V-6 Even Fire 196 and 231 CID)

    COIL IDENTIFICATION

    "There are two types of coils that are integral with the distributors. They can be identified by the different color tach leads and the part number stamped on the coil.

    The coil with the yellow tach lead (#1875894) is used on all Cadillac (except Seville), Chevrolet and Oldsmobile Toronado engines.

    The coil with the white tach lead (#1876209) is used on all Buick, Oldsmobile (except Toronado), Pontiac and Cadillac Seville V-8 engines and all V-6 engines.

    These two coils are very similar in appearance, perform identically, can be installed in any integral coil distributor, but are of opposite magnetic polarity. This was done to match the high tension coil to the magnetic pickup coil. The misapplication of these coils can cause hard or no starting and/or backfiring while cranking."
     
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  19. Aug 18, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Not entirely. I understand how the direction of rotation would require a change in polarity of the reluctor coil to maintain the correct phasing of the trigger signal. The Megasquirt document shows this pretty well.
    General Motors 7-pin HEI Ignition Control

    I don't see how this is related to the coil polarity. I will read your new post.
     
  20. Aug 18, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    The story with the starter and battery cable seems fishy to me. The engineers have plenty of distance to work with between the distributor and cables or starter, and putting some distance between them (or even an extra bit of steel shielding) seems like an obvious maneuver to prevent false triggering. Instead, I would be more inclined to believe that the stray field from the ignition coil, being right on top of the distributor, must be additive to the positive swing of the reluctor coil field (signal to module). A negative swing might cause an extra zero crossing and spurious trigger at the start of the positive pulse (see the drawing in the Megasquirt link). Capeesh?
     
    Last edited: Aug 18, 2020
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