Need help with HEI mod with external coil

  • Hi all,

    I wish to carry out the HEI and external coil mod on my 1996 K8.

    I require greater reliability having had two coils expire along with one Hall trigger/spark unit in 3 years of mx3 ownership?


    After following the links mentioned here on uk_mx3, all the step by step guides seem to show the coil types with the 'strap' connection to IG unit/cap rather than as on my coil type, with the 'post' connection. (I think mine is late dizzy labelled TOT57171 ?).

    • Am I correct that to disable the old coil, I am required to 'hack off' the coil tower that connects to cap?

    • And that the new set up will receive spark from 'MSD' tower mounted and tapped into dizzy cap from externaly mounted coil?


    On the back of my TOT57171 Hall trigger/IG unit there is a female spade connection that connects to a male spade protruding from coil.

    • what is this connection for?
    • and do I need to disable it too ?


    I have concerns about removing the unused coil completely as I think in doing so will expose the spindle bearing to the elements? is that correct?

    I would look into fabricating a heat shield/sink too, space allowing? although removal would actually allow air to circlulate behind the trigger unit.


    • Has anyone else with a stock K8 done his mod ?

    • does anyone have any concerns about attempting mod?

    • I have read that one potential down side of a stronger/reliable spark is increased rotor and cap post errosion? I only cover 2500+/- mls a year average so would this be an issue?

    • also would it just be false economy if I have to buy new cap and rotor every year as a result of mod?


    Any feedback, opinions etc would be greatly appreciated x

    thnx for veiwing
    kev B :D

  • I notice my post has had 40 odd veiws? is the reason I have no replies coz I talk shit? or is it cos no ones done the HEI and remote coil mod on a stock K8???? 'ANY' advice, comments, insults, welcome? (got to be better than no replys at all) :(

  • Hi mate, I looked at this post yesterday but didn't have any answers
    Anyhow I don't think there are any members on here that have done a HEI mod. Even tho your right the distributors do have their week points on the kl engines.
    Drop a line to I'm nearly 98% sure they will be able to help you having modified and provided the mazda/probe engines over such a long period.
    Failing that's perhaps try unless one of the state side guys here may have an answer.
    Keep us posted.

  • Might help if you post some pics up of the bits your concerned about.

    But i've never done that MOD and can't really help much.

    Might also be worth looking at why you have been having problems, what has been causing them.

    Here are some Guides:

    But for most people i'd take an if it aint broke don't try to fix it approach personally. Unless your dizzy is shot like the OP's i'd leave it alone.

    But if you do do it, please solder and heatshrink all joints.

    Check your wire colours, they are sometimes different between pre 1994 cars and later cars, and some USA colours are different also. So don't just blindly follow the guides, check the wires on your car.

    If money was not an option you could have looked up a coil on plug type setup as an alternative? Some people were looking into it a while back, but not sure if anyone ever did it…

  • Thanx you two x at least i know now from both your replies that there are other info routes to take as regards the HEI mod x
    My plan is not to dive into it blindly but consider it carefully before my current (3rd coils, 2nd hall triggers) give up the ghost! I dont know what could be causing the reliability of mentioned components other than heat/vibration effects?
    I am meticulous in my car maintainance and repairs (I hate 'scotchloc' connectors with a vengance) Love solder/heatshrink :D Ive probably developed a bit of a phobia of the mexy3's dizzy? as its spoilt my v6 experience on 3 seperate occasions :?
    I would love to post pics of car and probs, but quite simply. Im unsure how to, as a bit of an internet 'ludite' (only went on line last year?????) :oops:
    am I correct in thinking i need a 'photobucket' account? I'm able to upload pics on my FBk page without said 'photobucket' straight from my files/folders
    on my laptop? .
    Anyways imo UK MX3 is one of the best places for info of any type, I have spent countless days!! on its pages, its simply Knowledge! and knowledge is 'power' :? I have recently however wandered over to the 'darkside' and registered on 'ukpoc' but as yet have not had notification of reg? I am able to view topics but not reply etc, also cant find a search field either?
    MOT tomoz at 2pm :( 50/50 at mo? concerns over emissions and clicking DSft (os)? we'll see????? :respect: to UK MX3 one and all. kev B

  • It works like this:

    Every time you view an image on a website it uses up BANDWIDTH.
    A 1MB image would use up 1MB of bandwidth every time someone looked at it.
    The people who host the image have to pay for their bandwidth usage.
    If we let people upload images directly to our website (like you do on facebook) then we would have to pay for that bandwidth and we would not be able to afford to keep the website going.
    By hosting the images on other websites (e.g photobucket) we avoid paying for the bandwidth. Photobucket etc don't mind you doing it as they want people to use their website.

    You upload the image to any image host website (facebook might even work).
    Then look at the image on the internet, right click on the image, select VIEW IMAGE INFO, a new window will pop up, look for where it says location and copy the link (It will start with HTTP: and end with .jpg). Then when you want to add an image in your post click the 'Img' button, then past the link to the image, then click the 'Img' button a second time.

    If you get stuck let us know and we can help out further.

  • I would ask a seperate question if you wanted help diagnosing what might be causing your dizzy to fail.

  • Thanks for your time spent actually teaching 'an old dog new tricks' guys! lol x will try image upload soon? kev B

  • I also had a flawless K8 distributor that went bad without warning during my engine swap - caused all sorts of random issues! I chose to do an HEI/external coil swap and have loved it ever since. I can actually hear the difference made by the stronger spark. I'm with you concerning Scotchlock connectors, so don't use them.

    I assume you can get the MSD Power Tower,; it is part of the MSD coil wire set. That set now includes connectors for the Blaster 3 coil, not the Blaster 2. Take all the coil related stuff out of the distributor, but be sure to leave the cam angle sensor! There is a small block that closes off the side of the distributor. I trimmed everything off of it leaving only a blanking plate. A little silicone sealer there and the distributor is weather tight again.

    As for distributor cap wear, I don't see a problem, and if you get right down to it, a good used one makes a good starting place for adding the Power Tower. Go for it!

  • Hi fella, strange thing the human mind, Id pushed aside all thoughts of doing the mod, or simply been sidetracked by the excellent reliability of my current dizzy! That now said, It may have heard me?????

    I have the ability and materials to do the job and due to having two working dizzy's now I plan to butcher one, do the mod, then if im in anyway unhappy, i will mod in such a way that it woulkd be totally reverseable if need be?

    I know you say remove all coil etc which i originaly planned to do and then mount a flat heat sink plate to the base of the hall trigger unit which would extend outwards and be cooled by air ducted up from front splitter some how? The cavity exposed by the coil removal, i would cover with a section of fiberglass tube cut slightly deeper than the coils depth so that when the three cross head screws IN the dizzy are done up, they nip down on this and protect the spindle/bearing from the elements?
    The only thing that troubled me about coil removal on all the online guides, was that none of them seemed to deal with the issue of this connection…...

    ….... and what it actually does??? Both the dizzy's i have are the late ones, type: TOT 57171 K834 E ...............It looks too important just to plug up with silicon :(

  • I had an earlier model OBDI distributor to work with. Do you have a schematic of your distributor? If so, please post it so I can compare with the early unit.

    Just as a note, your connector scheme seems very different than mine, but I think one or more of the links here has your distributor in mind.

  • Sorry but thats one of my probs Stevesie, I don't have a WD of the dizzy connections/ layout internally, of the later type 'tot 57171' ???? The Chilton repair manuals etc show WD's for 1993-5 ? (I have a PDF digital copy)

    My guess is that your 'mod' on an early dizzy is of the type which requires the cutting of the 'STRAP' type coil connection??? If you look to the foot of the posted picture (above), below the lowest line of type in RED, at the word 'Halltrigger' between the 'gg' youll see the LATE type 'POST' coil to cap connection? that i have on both my dizzy assemblies?

    My 2nd GUESS about the connection questioned in the pic above, is that it may be the main conditioned (by ECU) signal connection to coil pimary winding? enableing switching/timing and hence output of HT voltage from secondary winding to plugs???? I really hope someone could/would correct me on this question/statement :shock:

    Off to bed cos I'm trashed with 'hayfever' so AFK!! :( kev b.

  • You are correct, I have a 'strap' distributor. Correct me if I'm wrong here:

    1. The wiring plug shown on your coil is the 'three wire' connector.
    2. You don't show the connector on the hall sensor (This is the cam angle sensor), but I'm guessing it's the 6 (or five plus blank) connector.

    If 1 and 2 are true, just leave out the coil entirely, make a blanking cover for its hole in the distributor and make the connection using the diagram from the last link you posted (the one by Nd4SpdSe). It would be the first of the diagrams in that link. You're absolutely right that the spade connector is the primary wire to the coil. Check the wire colors (crass American spelling!) on the plug to verify you have the right ones.

    Steve Seiter


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