Installing points conversion, and HEI System function, tests, and modification.

Discussion in 'Buick FAQ' started by LARRY70GS, May 13, 2012.

  1. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I'm writing this because this is a frequently asked question (FAQ) on V8, and one of the first modifications owners make to an older car, is to replace the points. The points ignition has been around for a long time, and is very reliable, and easy to work on (GM), but it isn't maintenance free. Despite all the hype out there, there is no performance to be gained by replacing points in most stock and mild combinations. There may be some drive ability gains from a hotter ignition, including faster starts, and longer spark plug life including resistance to fouling.

    This is how the stock points system works. Extending from the firewall engine harness connector(below the brake booster), is a calibrated length of special resistance wire. This wire does not extend all the way to the positive side of the coil. In the harness, it is joined by a wire leading from the "R" terminal of the starter solenoid, and from there, it extends to the positive side of the coil. There is a shorting switch inside the starter solenoid. When the starter motor is cranking the engine to start, the shorting switch inside the solenoid, sends battery voltage through the yellow wire to the coil positive, effectively bypassing the resistance wire. Once the engine starts, and the key is released to the run position, the yellow wire ceases to supply voltage, and voltage flows from the firewall via the resistance wire. This drops the running voltage so that point life is maximized.

    To test the system for proper functioning requires a volt meter. Connect the voltmeter between the positive side of the coil and ground. Turn the ignition switch to the run position. The reading should be 5.0-5.5 volts. It is important that the ignition points be closed for this test. If the points are open, the voltmeter reading will be full battery voltage. Bump the engine over until the points are closed, and check again. Again, 5.0-5.5 volts is the normal reading with the engine stopped, ignition key in the run position, and the voltmeter connected between the positive side of the coil and ground. The second part of the functionality test requires that you pull the coil wire out of the distributor, and ground it so the engine will not start. With voltmeter connected as before, crank the engine continuously, and observe the voltmeter. The reading should jump from the previous 5-5.5 volt reading up to 9 volts minimum. If it does not, it indicates a problem with the shorting switch inside the starter solenoid, or a wiring problem between the "R" terminal of the solenoid, and the coil. This will result in hard starting when cold.

    If you are installing a points conversion, it is important to READ the instructions and determine if the system requires full battery voltage, or if it needs resistance on the primary side of the ignition. If it requires resistance, you can leave the stock resistance wire in place, or add a ballast resistor if the stock resistance wire has been replaced sometime in the past by you or a previous owner. In any case, if you cannot use the stock wiring including the resistance wire, you either have to run another wire that carries ignition on battery voltage, or you need to remove and replace the resistance wire including the wire from the starter solenoid. The right way IMHO, is to remove and replace the wiring. The easiest way to do this is to open the wrapping on the engine wiring harness. Then remove the bolt in the center of the engine harness connector at the firewall, and unplug the front half of the connector. The wires push in from the front with a metal "barb type" of connection. The barb can be compressed with thin nose pliers, and the wire will pull out from the front. Then you simply unsolder the the barb connection and attach it to a length of 14 gauge wire, and snap it back in to the firewall connector, and plug the connector back onto the firewall, tightening the bolt. Run the wire along the harness, crimp on the proper connection, and attach it to the positive side of the coil. Most if not all Pertronix, need full time battery voltage. GM large cap HEI distributors need full time battery voltage.

    Below is a picture and link for the barb type terminal that clips into the front half of the the engine harness connection at the firewall.

    Attached Files:

    Last edited: Mar 6, 2019
    Donuts & Peelouts likes this.
  2. desolator

    desolator Johan

    I'm putting in the crane cams adjustable vacuum advance kit in my hei dist. It's going in my Buick 350. Is the crane kit enough or do I need to do some more mods with the dist?

  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    See the Power Timing thread in this Forum.
  4. ssbeane

    ssbeane '69 Skylark Custom

    Larry70GS are you saying that we should remove the section that runs from the solenoid to the resistance wire? As I understood it, the resistance wire is only hot in the RUN key position while the solenoid section is only live in the START key position. If I were to remove the solenoid section of wire, wouldn't there be no charge going to the coil in the START position?

    I may just be reading this wrong or maybe I misunderstood something. :Do No:
  5. buick64203

    buick64203 Just plum crazy Staff Member

    Just as an FYI, the connectors used in our cars are called, "Packard 56" terminals and connectors. The one in question is called a "split tab male terminal". They are readily available if you Google it. Plus its a real PITA to uncrimped those connectors. If you have a notion that you might one day convert your car back to stock, I would suggest you leave the resistance wire in the harness, and just remove the resistance wire terminal from the bulkhead connector and tape it off. Get a new Packard 56 terminal and install it with a new wire crimped in place. That way the resistance wire is there, still in the harness and can be converted back to points easily. I did this with my black 71 as I have an MSD setup in it. Even in its modified state, I have cut anything up on that car.
    22racer likes this.
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    The resistance wire is hot in the crank, and run positions. You can confirm that by simply connecting a voltmeter between coil positive and ground as described in the first post of this thread. The solenoid wire bypasses the resistance wire during cranking. Again, you can confirm this by running the test described in my first post. No harm in leaving the solenoid wire in place, but most people remove it along with the resistance wire. It's kind of redundant when replacing the resistance wire.

    If you see yourself possibly going back to points one day, do as Jason describes. Leave the wire in the harness taped off.
    22racer likes this.
  7. ameier29295

    ameier29295 Member

    Hi Larry,

    I am hoping you can help me with my wiring question on my 70 GS. I am changing over to a 1 wire, internal regulated alternator along with moving to a stock HEI from points. My goal is to eliminate all the extra wiring under the hood. Here is where I am at: I have removed the resistor wire and the voltage regulator wire from the fuse block at the firewall. I know that the "R" terminal on the starter plays a part in the system but really not sure how to include in back in the loop. Can you walk me through the changes I need to make and more importantly explain why so I can clearly understand?


  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    The resistor wire and the wire from the R terminal of the starter solenoid are joined together. The wire from the solenoid is the bypass to the resistance wire. The resistance wire extends from the firewall for a calibrated length, and then the bypass wire attaches to the end of the resistance wire and continues to the + side of the coil. You have to cut open the harness and you can remove the whole thing. Replace it from the firewall directly to the HEI feed with a length of 12 or 14 gauge wire.

    As far as removing any voltage regulator wires, I don't think that is advisable or necessary. I'd leave that alone. I converted my stock 70 alternator to a 12 SI 94 AMP internally regulated alternator . All you need to do is bridge 2 wires on the regulator plug, and move one wire from the 2 wire plug into the alternator. I got the Alternator from Jamie on this board. I would direct a PM to him about wiring modification. Here is the thread,
  9. mikky7

    mikky7 New Member

    The crane kit enough or do I need to do some more mods with the dist?
  10. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Depends on the distributor and everything else about your combination. More information, way more:)
  11. cobra2

    cobra2 Well-Known Member

    Thanks Larry, now I know why the HEI falls down when it gets hot, Already ordered the new wire to swap it out.. Craig
  12. austxsteve

    austxsteve Well-Known Member

    For us rookies, could I ask a huge favor please. I don't care if it is hand drawn, photos or a PowerPoint slide but would it be possible for someone to add a drawing to this thread showing their wiring please? I have a 455 HEI GM and I think original 350 points/stock wiring. It would be very helpful if it was something like;

    Inside the dash run a new wire from (ABC) see photo detailing the connection
    through the firewall and attach to the HEI.
    In between you need a connector to branch off to (DEF). see photo
    I ordered the parts via XYZ company and these are the part numbers.

    I know I am asking a lot, but if I read a How-To, I sort of grasp the concept... however when I can see pictures and/or diagram I really get it.

    Thank you and blessings,
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Steve, first, there is no difference between 350 and 455 point wiring except possibly the length of wiring, maybe not even that. Second, there is no reason to even touch any wiring inside the car whatsoever. If I thought a diagram would help, I'd draw you one. Fact is, it's really very simple. All you need to do is first, open up the engine harness. They are usually wrapped in tape. Cut it open. Then find the lead that is attached to the + side of the points coil. Trace and isolate that wire all the way back to the firewall. Mark the wire where it goes into the firewall connector. Then remove the bolt in the center of that connector. Once you do that, you can unplug the entire connector. Remove the wire you marked by compressing the barb, and pulling the wire out from the front. Then replace it with a suitable length of 12 gauge wire, and run that to your HEI BATT lead. That is it. Year One makes a ready made wire with the barb on one end and the HEI plug on the other. It's part # L00510. It doesn't get any easier than that. Some guys want to run another wire from the fuse block, use relays, and make it more complicated. That isn't the way I have always done it. Here is the Year One HEI lead. Plug and play.
  14. 2001ws6

    2001ws6 last of the v8 interceptors

    Do everything Larry just said and you'll be fine, It really is easy. Dont over think it.
  15. CyberT

    CyberT Silver Level contributor

    Will there be any problems if I use the Delphi #2971859 male terminal without rear “wings”?
    YearOnes Power feed wire for all H.E.I. made with 12 gauge seems to use this wing-free terminal.

  16. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Should work.
  17. OHC JOE


    Just ordered one for my pops car I know we didn't do this
    21.99 shipped also got a catalog why not
    Thanks Larry
  18. 71 GS

    71 GS Well-Known Member

    Thanks for the reply Larry, some great information regarding installing my 12v HEI GM electronic distributor. So I took your advice and started to remove the tape from the wire harness. I traced the + red wire from the coil along the harness and straight away I noticed the red wire is spliced/ joined into a white braided type wire that runs two ways, one going down around the engine I think to the starter ,Question do I trace that wire and remove this end as well ? The other end as you explained all the way to the connection box on the fire wall near the brake booster . So I remove the bolt & the front half of the connection box and will be ready for the next stage.
    Thanks regards Darryn 71 GS
  19. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yes, remove the wire to the starter. When you remove it from the firewall connector, save the entire thing in case you ever want to go back to points. The braided wire is the resistance wire.
  20. 71 GS

    71 GS Well-Known Member

    Hi Larry, I have stared on the next stage of installing the new distributor. I made some Mark's where the old distributor was sitting pulled the cap off and took note of the position of rotor & made a straight line mark on the engine block .
    I tried to install the new distributor I had trouble lining up to those Mark's and moved the oil pump shaft a 1/4 turn so the new distributor would sit down and my Mark'swould line up . When started the engine my timing mark was way off when using a timing light and the engine didn't sound right . After reading up about TDC I need to start again, find TDC on compression stoke thumb over no 1 spark plug hole trick, look down at the pulley mark hopefully its on zero, mark my number 1 on new distributor cap in relation to the old cap where it had an old no1 painted on the cap . Get my new rotor facing the no1 mark on the new cap and start the firing order process . Please let me know if I've got all wrong as explained, as i don't want to damage anything.
    Thanks regards Darryn

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