Jump to content
z32 fairlady

Coil Pack Conversion - More Info Needed

    Recommended Posts

    3 hours ago, Captain Obvious said:

    So I haven't thoroughly researched the name "Wasted Spark", but I always thought that the "waste" was referring to the spark on the exhaust stroke that didn't do anything. Didn't cause any harm, but it was "wasted". If that's the true origin of the name, then what you said about the spark jumping backwards doesn't have to be the case.

    It does if you want to use it as wasted spark.  The system pulls the spark from one plug and pushes it the other.  The direction is the same whether it's on the power stroke or the exhaust stroke.

    It's pretty interesting to look at a set of plugs from a wasted spark engine.  Half of them will have the center electrode burned down and the other will have wear on the grounding strap.  It's weird.

    Share this post


    Link to post
    Share on other sites

    1 hour ago, Zed Head said:

     

    It's pretty interesting to look at a set of plugs from a wasted spark engine.  Half of them will have the center electrode burned down and the other will have wear on the grounding strap.  It's weird.

     That rang a bell from the distant past. I remember an old timer telling me about condensers of different values causing either the center electrode or the ground to burn down more than the other.

    Share this post


    Link to post
    Share on other sites
    13 hours ago, Zed Head said:

    It does if you want to use it as wasted spark.  The system pulls the spark from one plug and pushes it the other.  The direction is the same whether it's on the power stroke or the exhaust stroke.

    I get that. My suggestion was that you could use COP's and connect them in parallel pairs and do the same thing on the low voltage side instead of sharing a high voltage coil between two plugs. You would still be wasting a spark, but it's not the traditional "two plugs in series" circuit.

    Gives you the same distributor-less function as the traditional wasted spark system, but you wouldn't get any weird electrode erosion and the energy used to fire the plug on it's exhaust stroke would not be subtracted from the plug that really matters.

    Instead of "two plug in series being fed from the same coil", you could use "two coils-on-plugs in parallel being fed from the same control source".

    Maybe it would be clearer if I whipped up a couple simple sketches?

    Share this post


    Link to post
    Share on other sites

    It's clear.  If I recall correctly, some engines have been built with a separate mechanical distributor for each spark plug.  Mechanical COP.

    Lots of ways to redescribe something.  Not sure which will help the discussion.  At least we're splitting fuel from spark, which is always important for understanding.

    Share this post


    Link to post
    Share on other sites

    Question for @z32 fairladywhy are you considering this modification?

    The reason I ask is that I am also considering it, and your answer may help me clarify my own situation. I’d like to just do this once.

    Right now I have an engine being built with no ignition system at all, so anything I get will be new parts. I’m trying to make the right (for my situation) decision the first time. The new engine is an F54 block with P90A head converted to mechanical (non-hydraulic) rocket pivots, running a stage 1 cam and rebuilt SUs. I may convert to DCOE FI (Jenvey) or the like later. 

    For posterity, these are the options I’ve identified so far:

    • A 240z distributor (hard to find, hard to get parts, solid performance)
    • A 240z distributor + Pertronix (easier to maintain, no real performance improvements)
    • A ‘79 280zx distributor (requires a particular base, strait forward if you have the parts)
    • A later ZX distributor (no balast resister, hotter/better spark, tach won’t work, needs a recurve, vacuum advance is “wrong”)
    • Mallory Unilite (no longer manufactured, hard to find, no vac advance)
    • GM or equivalent HEI distributor (available anywhere, requires machining/fabrication/module/etc.)
    • 123 distributor (great performance, poor quality control, several failures documented in this forum, tunable on the fly, set and forget)
    • COP + DIS (great performance particularly at high RPM, damned expensive, requires a pro to tune, clean look, as far from “period correct” as you can get)

    I’ll put this question to the group: if the points distributor is on one end of the spectrum and the DIS is on the other end, how does one find the sweet spot for their car?

    Edited by Matthew Abate

    Share this post


    Link to post
    Share on other sites

    I bought a '79 ZX distributor as it had the best "curve" from the Excel spreadsheet floating around here.  Wired it like the atlanticz.ca Tech Tips without any issues.  Works great, tach and all.

    Share this post


    Link to post
    Share on other sites

    You left out 280Z distributor + external ignition module.  GM HEI, MSD, Crane, and other modules.  Some of them are programmable.  The 280Z distributor has the variable reluctor trigger, which is very solid and dependable.   

    Share this post


    Link to post
    Share on other sites
    1 hour ago, siteunseen said:

    I bought a '79 ZX distributor as it had the best "curve" from the Excel spreadsheet floating around here.  Wired it like the atlanticz.ca Tech Tips without any issues.  Works great, tach and all.

    Oh, cool. I’ll search for it.

    @Zed Head, thanks for filling in the gaps!

    Share this post


    Link to post
    Share on other sites

    @siteunseen,

    This thread? 


    Back to my question above: given the options I listed and the additions from @Zed Head, are there any general recommendations or categorical options?

    The ‘79 distributor seems very hard to find, putting it in the same bucket as any S30 distributor. The HEI options seem interesting, but I wonder if it wouldn’t be nearly as much work/money/time to get it going as the COP/DIS options. Obviously the specific parts chosen can drive up costs, but I’d love to hear from someone who has tried a few or several options.

    I know there is no “best.” Just looking for sign posts to point the way.

    Edited by Matthew Abate

    Share this post


    Link to post
    Share on other sites

    The ZX distributor is the common go-to and a good sweet-spot between the extremes. The tach can be made to work.

    Share this post


    Link to post
    Share on other sites

    I’ll admit that I’ve only been looking for about a week and haven’t posted a WTB in the classifieds, but so far I have not been able to find a rebuilt ‘79 at any price.

    In an effort to get back on topic and make this thread helpful, here are some questions to the guys who lost the distributor:

    • Why did you do it (frustration, experimenting, parts availability, etc.)?
    • If you were starting from nothing and could choose anything, what would you do and why?
    • Was a DIS “worth the cost” to you (someone dependent on your previous answers, I guess)?
    • Are there any big flags we should be aware of before choosing the DIS path (outside of the technical details of doing it correctly)?
    • Did anyone revert to a distributor? Why?
    Edited by Matthew Abate

    Share this post


    Link to post
    Share on other sites

    I've used the z32 cas installed onto the turbo distributor shaft with the z32 ecu and nistune.  I changed the turbo at the time of conversion and can't honestly say that I gained any power from the coil packs but I could run a stock plug gap at 26psi.  

    Share this post


    Link to post
    Share on other sites
    2 hours ago, Matthew Abate said:

    I’ll admit that I’ve only been looking for about a week and haven’t posted a WTB in the classifieds, but so far I have not been able to find a rebuilt ‘79 at any price.

    In an effort to get back on topic and make this thread helpful, here are some questions to the guys who lost the distributor:

    • Why did you do it (frustration, experimenting, parts availability, etc.)?
    • If you were starting from nothing and could choose anything, what would you do and why?
    • Was a DIS “worth the cost” to you (someone dependent on your previous answers, I guess)?
    • Are there any big flags we should be aware of before choosing the DIS path (outside of the technical details of doing it correctly)?
    • Did anyone revert to a distributor? Why?

    I ran Megajolt on my previous Z because I wanted a stout, fully-programmable ignition system at a low cost as I was running triples for fueling. It's easy to setup, tune, and is rock solid. I highly recommend Megajolt if you're considering standalone ignition but want to keep the carbs.

    I'm running a 123ignition distributor on the current Z because I again wanted a fully-programmable ignition system but this time I also wanted to keep a period look. There is no other good reason to stay with a distributor if you're considering a DIS, IMO. The 123 is not as robust and high performing as Megajolt but it's as good as it gets for distributors.

    • Like 1

    Share this post


    Link to post
    Share on other sites

    Just FYI... The ZX ditributors with the E12-92 module can be used just like the ones with the E12-80 module. If you have or can get a ZX dizzy with the E12-92 it will work exactly like the E12-80. When you just use the C and B connectors leaving I & W disconnected gives the same timing curve as the E12-80 module. The E12-92 has been running just fine on my series 1 240Z since 2003. Another reference is in this thread.

    https://www.zcar.com/forum/10-70-83-tech-discussion-forum/116513-e12-92-e12-80-a.html

    • Like 2

    Share this post


    Link to post
    Share on other sites

    I posted in this thread about using an MSD or Crane module but I don't think that their programmability is very complex.  Their ad copy is deceptive.  Here is a system that does what I was thinking of.  Lots of ways to get spark control, especially in today's programmed world.  Somebody has probably developed an app that will let you use a "phone" to run your engine.

    https://www.cbperformance.com/CB-s-Black-Box-Programmable-Timing-Control-Module-p/2013.htm

    Share this post


    Link to post
    Share on other sites

    On 11/30/2019 at 5:46 PM, Matthew Abate said:

    @siteunseen,

    This thread? 


    Back to my question above: given the options I listed and the additions from @Zed Head, are there any general recommendations or categorical options?

    The ‘79 distributor seems very hard to find, putting it in the same bucket as any S30 distributor. The HEI options seem interesting, but I wonder if it wouldn’t be nearly as much work/money/time to get it going as the COP/DIS options. Obviously the specific parts chosen can drive up costs, but I’d love to hear from someone who has tried a few or several options.

    I know there is no “best.” Just looking for sign posts to point the way.

    Yes, It was done by Walter Moore. I'd forgotten who created the spreadsheet.

    My dizzy has those numbers stamped on the outside body and the weights were 18 each for 36 total advance. It may not be an actual '79's but it's close enough for me. Good luck Matthew. You've made good decisions so far, I'm sure that will remain true. Cliff

     

    Share this post


    Link to post
    Share on other sites

    I found an article that shows how MSD's ads are deceptive.  They describe set-point timing retarding as "curves".  They're not curves.  They're just rebranding their rev-limiter technology.  Pretty sad, MSD used to be top of the game.

    https://bangshift.com/general-news/tech-stories/engine-tech-how-a-programmable-ignition-can-make-anyone-look-like-a-pro/

    image.png

    Share this post


    Link to post
    Share on other sites

    @Matthew Abate

    The car is a numbers matching car and I intend to keep it that way with the 4 speed as well.  I am in the process of getting the car to a running and reliable state.  Next after some recovery, financial wise, is body work.  At this time the engine will be out and I intend to do a rebuild while upgrading choice components.  I am building the car for longevity along with some modern refinements for "ease of maintenance".

    I am a one and done type of person and put forth my effort up front in the research so I can get it done right the first time.  My 4 month old son is my motivation and I hope to give him this car one day.  I may get some criticism for the direction I am going but I can care less.  What I do care about is the love and knowledge bomb dropped in this thread.  Now I need to find some time to sit down and digest it all.

    Thank you all.

    Edited by z32 fairlady

    Share this post


    Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now

    ×
    ×
    • Create New...

    Important Information

    By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.