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Six Cyl GM Electronic Distributor Conversion

Discussion in 'The Hokey Ass Message Board' started by GMC BUBBA, Dec 5, 2008.

  1. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    Another tech for the GM Six guys. I have used many petronix over the years and have warranted quite a few , some work some dont .
    After working on and teaching ignition systems for 30 plus years i have found the Chrysler electronic distributor and the GM HEI control module to be the best ever system for system!.
    So lets build one with those parts....:eek:
    Step one GM six distributor 40's up t0 1962 ???

    [​IMG]

    Remove contacts and upper plate assembly ....

    [​IMG]

    In a future post i will address total rebuild, in this case the distributor had already been overhauled etc and my main objective is to make her electronic...

    Remove the brass adjustment screw and post by grinding off the pivot head from back side and re-install.

    [​IMG]

    See next post for parts needed.........hate those time outs :eek::D
     
  2. Subscribed. Seen it on other sites, looking forward to yours.
     
  3. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    You will now need to buy two parts , suggest napa etc for quality etc.
    Purchase a reluctor ( the center piece ) and a pickup coil. In my case i used a v8 pickup coil ( i think it is the same as a six) and a six cylinder reluctor.. ( prices vary so shop some:)).

    [​IMG]

    Note you may have to remove the reluctor from the plate by grinding off back side of rivit.

    [​IMG]

    Note : Reluctor has six teeth for the six and eight for V8...(post coming on V8 chevy conversion)
    Reluctor is a little smaller inside diameter than distributor cam . Carefully machine to fit. Should be just a slight press fit ( will use loctite sleeve mount in final assemble).
    ( I had 10 made next door if you need me to ship you the parts etc...havent seen my invoice but they are always fair)

    Install reluctor aligning teeth on reluctor with distributor cam high points.

    [​IMG]

    Mount reluctor in case using the contact point adjusting screw and clearance to .006 with feeler gauge making sure reluctor doesnt hit pickup contact. Tignten screw.....you could rivit small hole in reluctor but i usually dont they dont seem to ever slip???
    We can now run in machine to test ( step not required with running car etc)

    [​IMG]

    Note that i also made wires a little cleaner and used a new connector plug from parts store etc. Ran wires thru old hole on case and installed rubber gromelet.

    YOUR DONE ( almost)

    I will remove reluctor wheel and final press fit using loctite sleeve mount ( green) although i feel any locktight will work fine.

    You may need to grind some off the heal of the reluctor for clearance and the inside of the distributor cap will need a dremel tool as well ,to final fit all parts.

    You now own one of the most dependable distributor known to man...
    Winner hands down..................:D:eek:

    Note..........I ran this one at 8000 rpm for about 10 minutes , one of the cleanest distributors i have ever ran.!!!! Control module next.......
     
    Last edited: Dec 5, 2008
  4. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    Now that the distributor is done and tested

    lets hook it up to a coil and control module and make some spark!!




    [​IMG]

    [​IMG]

    I have been using a aluminum coil cover from the "dickster27 " and i had him make me up a box of a simular aluminum holder to fit a GM four pin control module to match. ( GM four pins are anywhere from 25 -28 bucks)
    I have a machine to test your old ones if ya want to box em up and ship them to me.....shipping only charge for hambers)
    Great module , will handle low resistance high out put coils super internal circuits making it one of the best ever.
    Actual wiring later on.....
    Module and case MUST be grounded ! Lets hooker up and spin it.........

    SUPER Six for sure......................................

    Questions , comments ?????????????????????????:eek::)
     

  5. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    Some more pics...........

    [​IMG]

    [​IMG]
     
  6. So, if you have a later 250 with a big ol ugly HEI what do you recomend?
     
  7. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus


    The early 230-250-292 all used a small base contact point distributor. I think the same conversion would work as well with this unit.
    Thats the joy of this conversion , it opens the door to converting just about anything. I also machined up some v8 units as well. Fits right over the orginal distributor cam.
    Could machine to fit over the old mallory cam etc ..theres no end to where this application could go.
    Put the module in the glove box with a aluminm heat sink. Hide the module anywhere up want etc.??????????????????

    Friends dont let friends use the big ole hei......:eek::D
     
  8. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

  9. Canuck
    Joined: Jan 4, 2002
    Posts: 1,104

    Canuck
    Member

    Bubba

    A couple of questions to help clarify in my mind.

    "Reluctor is a little smaller inside diameter than distributor cam . Carefully machine to fit. Should be just a slight press fit"

    Is it the reluctor that you machine to fit over the cam or the cam that is machined to fit the reluctor?

    Anything special if it is the reluctor that is machined?

    "grind some off the heal of the reluctor for clearance and the inside of the distributor cap will need a dremel tool as well ,to final fit all parts."

    By "heel" do you mean the bottom of the reluctor?

    On a V8 distributor is it possible to set it up so no clearancing is required on the distributor cap?

    How does this compare for a ignition versus keeping the points and using a Ford TFI-IV module? I know point rubbing block wear would still be a issue.

    I guess that is more than a couple of questions.

    Trying to set my car up to use as many original parts as possible so if there is a breakdown parts are available in any small town. Working on a 66 Buick distributor.

    Thanks

    Canuck


     
  10. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    Glad to help
     
  11. Well, the HEI will stay for the short term when I get the car on the road (good running engine). After shakedown I will be bugging you when I get to stage 2. You have helped pals of mine and I would love to do some business with you and your experience!
     
  12. power58
    Joined: Sep 7, 2008
    Posts: 432

    power58
    Member

    Bubba done done it again. Fantastic Tech. Great work coming out of your shop. Thanks for the Tech.
     
  13. roddinron
    Joined: May 24, 2006
    Posts: 2,676

    roddinron
    Member

    Damn, and I just went through all the crap to adapt a s-10 v6 dizzy to mine. Works and looks good though (small cap), but this looks easier.
     
  14. Once again nive tech bubba - this is the kind of REAL Tech that Hmabers need. Simple, cheap and VERY effective stuff, esp when compared to a lot of the overpriced stuff out there.

    Those mopar elec distributors are the best - PERIOD. Can you pls elaborate on the control module you used? Price, avail, where to get em etc?

    Rat
     
  15. Spedley
    Joined: Mar 5, 2004
    Posts: 392

    Spedley
    Member

    Very cool!! This'll come in quite handy...
     
  16. Bonehead II
    Joined: Apr 18, 2005
    Posts: 437

    Bonehead II
    Member

    Hey BUBBA..That's great, now I know what to do with that old Mallory I got. question do you leave the weights and springs in as well.
     
  17. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus


    Yes , all the stuff works as orginally designed. Clearance can be a problem with pickup unit,but usually works very well.
    This pickup will trigger any of the ignition modules ford duraspark, chrysler and gm. I think the GM is the best bang for the money.......
     
  18. buffaloracer
    Joined: Aug 22, 2004
    Posts: 816

    buffaloracer
    Member
    from kansas

    Thanks Bubba. Great work as always.
     
  19. great work! pic's are great also.
     
  20. smschriefer
    Joined: Nov 7, 2008
    Posts: 60

    smschriefer
    Member

    GMC Bubba you are God-like! I just rebuilt my stock distributor and sadly placed it on the shelf since my monsterous HEI was still working fine, but I think it will get changed out real soon. ;)

    I looked up parts at NAPA by selecting a 1980 Dodge D150 with a 225 L6 engine. Part numbers are ECHMP802 for the reluctor ($4.99) and ECHMP805 for the Pick up Assy ($31.49). Are these the correct parts? If so, I see a cleaner engine bay in my immediate future!

    You rock and if I have any issues I will PM you and I look forward to your tech on the control module wiring.
     
  21. Guitar Guy
    Joined: Nov 24, 2008
    Posts: 340

    Guitar Guy
    Member

    Those HEI are great becouse you dont have to adjust points but the points on a GM distributor are easy to set compared to chrystler and ford
     
  22. Kreepea_1
    Joined: Sep 17, 2007
    Posts: 501

    Kreepea_1
    Member

    Great post GMC Bubba! I noticed your starting point for the distributor applications was the '40s. I'm lead to believe that Pertronix also starts with '40s (when I provided them the PN & SN from my '38 Chevy they said they didn't have anything for it). Can you or maybe some of you other HAMBers with way more knowledge on the distributors, explain why these electronic conversion aren't applicable to the late '30s distributors?

    Thanks
     
  23. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    I think some of the early chevys are much smaller in diameter. Measure the top circle with the cap removed and i can compare to the 40s unit.
     
  24. 6inarow
    Joined: Jan 24, 2007
    Posts: 2,361

    6inarow
    Member

    Chevy distribotors from 37-62 should all interchange
     
  25. HEATHEN
    Joined: Nov 22, 2005
    Posts: 8,558

    HEATHEN
    Member
    from SIDNEY, NY

    Right. The only difference is that the steel camshaft engines ('37-'53 and '54 standard shift) used a drive gear of different material than the cast camshaft engines ('54 PG and '55-'62).
     
  26. Kreepea_1
    Joined: Sep 17, 2007
    Posts: 501

    Kreepea_1
    Member

    The top circle of my distributor is roughly 3-1/8" (O.D) and 2-15/16" (I.D). It's starting to look like I can convert to EI this winter.

    Thanks Guys!
     
  27. TagMan
    Joined: Dec 12, 2002
    Posts: 6,294

    TagMan
    ALLIANCE MEMBER

    "Chevy distribotors from 37-62 should all interchange"

    They'll interchange as far as fitting in the engine and meshineing the gear, but the earlier distributors had a much smaller cap that the later ones did.
     
  28. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    Ok I promised I would discuss the choice of the GM HEI control module:
    I have got a minute this morning to get er done….
    <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    After many happy years of contact point ignition the industry needed a new revised system. The old contact units had ( and still do) served us very well as long as the current levels at the ignition coil was kept below 4 amps. Any time the current exceeds 4 amps contact point life is decreased to a very low mileage.
    When I hear that &#8220;my points burnt up quickly&#8221; the answer is always the same . Your system is incorrectly matched , using the wrong resistance parts and the current level is simply too high.
    The HEI ( High Energy Ignition) was introduced in 1974 ( although I have a early Pontiac unit from a 1971 Pontiac HP engine) The advertising hype for the HEI states : No scheduled maintance, provides 35,000 volts ( if needed) and a increased spark plug life, and a 85% higher energy level that the point system..
    Eliminated are the contact points and breaker point cam by using a magnetic pulse generator to time the on /off of the primary circuit. Transistors are used in the controller to turn the current on and off as well as limit and control the current levels.
    The 4 pin HEI limits this available current to 5-5.5 amps.
    A contact point system may use a build up ( dwell) of 30 degrees . When the contacts close this current build up doesn&#8217;t happen instantaneously. At 1000 rpm this current rise to 4 amps could be 10ms ( mili sec) (see chart) and at 2000 rpm this time drops to approx 5 ms allowing time enough to build up only 3.2 ms. So with the contact point system available energy drops with increased rpm of the engine.
    At 6000 rpm the available current is approx 2.5 amps , thus the reason for dual point units in the early 60s..
    The HEI control module uses two features to give us a higher energy level at higher rpm.
    First the system uses a low resistance ignition coil (.5 ohms) that greatly reduces the time needed for the current to reach its maximum. The HEI can reach full current in about 3.4 ms.
    Points= 10 ms HEI=3.4ms
    Second a dwell control circuit reduces the time that current limiting is taking place, keeping the coil cooler and further increasing the reliability and life of the system.
    So we now know it&#8217;s a good choice &#8230;.right ????
    <o:p></o:p>
     
  29. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    Now lets discuss our application for this module.
    <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    First of all quality is a issue here but I have seen poor quality from everyone!! Just buy from a major maker and I think you will be ok. Delco is what we usually use but they are about 5 bucks higher. My next builds I am going to try the blue units from Speedway Motors etc. ($19.99) However I believe the Wells from Autozone will serve us very well.
    The pickup used in our distributor MUST be matched polarity wise with the control module. It is a npn driver circuit and needs a positive signal to fire correctly. ( crossed pickup will retard timing). The positive on the Chrysler is the male terminal and should be wired to terminal G on the control module for correct polarity.
    The module MUST be grounded not only thru the mounting screw but the back plate as well. Grind off the little lugs on the module if mounting on a flat surface to complete this ground. Use a SMALL amount of dielectric grease with the back plate as too much will do more harm than good.
    Use a low resistance coil to make the module ramp up the amps needed for good hot spark., I just checked a few on the bench here and found they range from 4.0 (Bosch Blue) all the way down to .2 (MSD Pro Coil), a couple Accell units was .9 and 1.1 ohms.
    It takes 1 ohm or less to make the circuit load to 5.5 amps , so I suggest less than 1.0 ohms. Most later electronic ignition system coils will work well.
    The controller will work with 1 and above it just wont be at max amps.
    <o:p></o:p>
    Wiring is :
    <o:p></o:p>
    Terminal<o:p></o:p>
    #B= Battery switched on off ( usually hooked to positive igntion coil terminal.<o:p></o:p>
    #C= Ignition coil negative ( switching circuit)<o:p></o:p>
    #W= Pick up from distyributor neg polarity<o:p></o:p>
    #G=Pick up from distributor ( positive polarity female connector Chrysler pickup)<o:p></o:p>
    <o:p></o:p>
    Oh well got to get some work done , will do a V8 conversion later this week…
     

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