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Oddfire And Dwell Meter?

Discussion in 'Early CJ5 and CJ6 Tech' started by Ollie2009, Aug 15, 2023.

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  1. Ollie2009

    Ollie2009 Member

    I connected my dwell meter to the coil to check point gap and got crazy readings (I had set them with a feeler gauge at .016"). Because of the "odd" dizzy cam lobe separation, will a dwell meter even work?
     
    Ollie2009, Aug 15, 2023
    #1
  2. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Analog or digital meter? An analog one should work ok as the inertia of the needle will "average" things out.

    A digital one may go bonkers :(
     
    Howard Eisenhauer, Aug 15, 2023
    #2
  3. Ollie2009

    Ollie2009 Member

    I tried both, neither gave me the correct 30* reading.
     
    Ollie2009, Aug 15, 2023
    #3
  4. 53A1

    53A1 Member

    I have an old needle type meter, that has 4,6,8 cyl. option and that's all I use. I set mine at 29 deg as I recall. MUCH better than setting gap with feeler gauge.

    After I set dwell, I unplug the vacuum advance and block line, lower idle so mech advance is not a factor and check timing mark (about 5 deg btdc). Thereafter, I reattach vacuum and bring idle back up. My engine seems to run very well and revs nicely so I guess it's working.
     
    53A1, Aug 15, 2023
    #4
    alpina72 and Lockman like this.
  5. Mcruff

    Mcruff Earlycj5 Machinist

    My old Sears dwell, point, tach meter works fine, no problems, you have something else going on.
     
    Mcruff, Aug 15, 2023
    #5
    vtxtasy likes this.
  6. Cj5dale

    Cj5dale Member 2023 Sponsor 2022 Sponsor

    What reading are you getting?
     
    Cj5dale, Aug 15, 2023
    #6
  7. FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    I used a digital dwell meter on my v6 for quite a few years with no issues....(before I went pertronix of course).
     
    FinoCJ, Aug 15, 2023
    #7
    Cj5dale and Ol Fogie like this.
  8. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    I just use a feeler gauge for setting points, and it has worked fine for me for more than 55 years.
     
    Oldpappy, Aug 15, 2023
    #8
  9. kenny78

    kenny78 Member

    Innova digital worked as expected.
     
    kenny78, Aug 15, 2023
    #9
  10. Cj5dale

    Cj5dale Member 2023 Sponsor 2022 Sponsor

    upload_2023-8-15_22-7-22.jpeg
     
    Cj5dale, Aug 15, 2023
    #10
  11. Ollie2009

    Ollie2009 Member

    I will recheck my setup. I do have an MSD 6AL ignition box. Does that matter?
     
    Ollie2009, Aug 16, 2023
    #11
  12. kenny78

    kenny78 Member

    Google says you must disconnect msd and go back to original to check dwell

    The Internet said it so 50/50
     
    kenny78, Aug 16, 2023
    #12
    Danefraz likes this.
  13. Ollie2009

    Ollie2009 Member

    I was afraid of that! Thanks for the info.
     
    Ollie2009, Aug 16, 2023
    #13
  14. termin8ed

    termin8ed I didn't do it Staff Member

    Trying to think...
    I don't remember disconnecting the msd on mine when I checked dwell. But that was a good 3+ years ago.

    Ran A LOT better setting the dwell than previously just using a feeler gauge
     
    termin8ed, Aug 16, 2023
    #14
  15. Mcruff

    Mcruff Earlycj5 Machinist

    MSD boxes fire multiple times when ignited, they also control the dwell.

    If your not old enough to remember.
    Multiple Spark Discharge
     
    Mcruff, Aug 16, 2023
    #15
  16. termin8ed

    termin8ed I didn't do it Staff Member

    Yes and no?

    Points control the dwell(off time)
    Msd produces more sparks so there is less off time between cylinders firing. But still need to set the points dwell.:shrug:
     
    termin8ed, Aug 17, 2023
    #16
  17. Mcruff

    Mcruff Earlycj5 Machinist

    Not on the oddfire unit, the points act only as a trigger unit, the MSD unit controls the dwell, that’s why I had to remove one set of points from my dual point distributor. At least that’s what the instructions tell you.
     
    Mcruff, Aug 17, 2023
    #17
  18. termin8ed

    termin8ed I didn't do it Staff Member

    I saw the dual points part. The msd would think it's a 12 cylinder engine.
    You still need to set the distributor to get the signal to the msd. From what I've read the msd sparks longer, but you still need to set the points gap(dwell) so the msd knows when to fire.
     
    termin8ed, Aug 18, 2023
    #18
  19. Mcruff

    Mcruff Earlycj5 Machinist

    From the MSD instructions remove or disable the trailing points, set the gap on the primary points, the dwell is controlled by the MSD unit afterwards as the points are now the trigger for the multiple spark control. The MSD does not fire longer it sends multiple sparks in a specified time.
     
    Mcruff, Aug 18, 2023
    #19
  20. Ollie2009

    Ollie2009 Member

    So it sounds like I just set the gap to .016" and let the MSD box set the final dwell. Does that mean as the points wear down, the MSD keeps the dwell at the correct 30* regardless of the point gap?
     
    Ollie2009, Aug 18, 2023
    #20
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