Spark Plug Reading

Discussion in 'Engine Topic' started by bkmont, Jun 24, 2018.

  1. bkmont

    bkmont Veteran Member

    1,001
    24
    Nov 14, 2010
    Pensacola, Florida
    Hey Guys,
    Please take a look at my plugs and tell me what you think. I do have a misfire. It looks like 4 and 6 could be the culprit, Those two look really rich.
    IMG_3573 (1).JPG IMG_3574 (1).JPG
     
  2. COPO

    COPO Veteran Member Lifetime Gold Member

    16,398
    283
    Sep 15, 1999
    Ontario, Canada
    Rich alright. Usually 1,3,5,7 will be richer due to the design of the intakes. I usually stager jet 1,3,5,7 two numbers lower. You could try a hotter plug in 4,6.
     
    Last edited: Jun 24, 2018
  3. bkmont

    bkmont Veteran Member

    1,001
    24
    Nov 14, 2010
    Pensacola, Florida
    Hi Mark,
    Do you think I could have an intake leak causing some of the variation? I did put the factory intake and valve covers back on it recently. I left the Crane Rollers in place, added the double gasket and trimmed the oil drippers.
     
  4. muscl car

    muscl car Veteran Member Lifetime Gold Member

    Any better pics so we can see the timing mark on the electrodes ???

    For a perfect plug you should see a parting line dead center of the radius " curve " in the electrode !!

    Before the radius .....not enough timing

    After the radius ....... To much timing
     
  5. COPO

    COPO Veteran Member Lifetime Gold Member

    16,398
    283
    Sep 15, 1999
    Ontario, Canada
    It's the crappy design of the Z intake. My 2,4,6,8 burns better than my 1,3,5,7 bank. You can run unlit propane along the intake to see if the rpm's increase but have a vacuum gauge or tach in your hand to see the changes if any cause you won't hear much from the noise but I think your intake is ok. How did you set your valves last time? I noticed a more steady idle and vacuum reading when I used the EOIC method. Before my rpm at idle would go up and down abit like I had a big cam and my vacuum gauge would go up 1" then go down 1". Now it's level. I haven't gone on a decent drive yet to see what my plugs will look like.
     
  6. bkmont

    bkmont Veteran Member

    1,001
    24
    Nov 14, 2010
    Pensacola, Florida
    How about these photos-
    IMG_3579.JPG
    IMG_3580.JPG
    IMG_3581.JPG
     
  7. bkmont

    bkmont Veteran Member

    1,001
    24
    Nov 14, 2010
    Pensacola, Florida
    I haven't messed with the valves. I believe the solid cam has been replaced with a hydraulic cam. Not sure what type.
    I'll try the leak test.
     
  8. COPO

    COPO Veteran Member Lifetime Gold Member

    16,398
    283
    Sep 15, 1999
    Ontario, Canada
    #3 color on the strap looks good but the rest differ. Set initial
    timing to 14* and if you have a back dial light set total to 36*
    with vacuum disconnected from the VA can and plugged with a
    golf tee.

    Plugs and wires that have low resistance also helps



     
    Last edited: Jun 25, 2018
  9. muscl car

    muscl car Veteran Member Lifetime Gold Member

  10. bkmont

    bkmont Veteran Member

    1,001
    24
    Nov 14, 2010
    Pensacola, Florida
    Thanks guys. I really appreciate the feedback.
    And the videos are great.

    I did do a quick resistance check on these cold ACCEL Shorty 576S plugs and it's all over the place. Maybe due to not getting good contact points with my cheap OHM meter. So I'm not sure of the accuracy.
    The OHM readings are:
    8 - 6.3k ----- 7 - 11.02k
    6 - 6.7k ----- 5 - 8.05k
    4 - 7.4k ----- 3 - 7.1k
    2 - 7.6k ----- 1 - 11.3k

    I'll dive into it deeper as time permits. Check the timing and put a vacuum gauge on it. Also wondering if the distributor might be causing the plug variability. I'm using a Ignitor 1181L pulse sensor setup. The plug wires are new NAPA 7mm wires. Flame Thrower coil with full 12v.

    Bryan
     

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