Spark Plug Spacing

Discussion in 'Technical' started by rhy_boy1, May 23, 2011.

  1. rhy_boy1

    rhy_boy1 New Member

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    Anyone know the spacing of 300ZX plugs?
    I had a look but cant find anything.

    I'm guessing 2.5mm?
     
  2. rom-vg30dett

    rom-vg30dett Always Broke

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    stock zed 1.1mm, boosted and highly modifed around 0.8mm. You could be anywhere in between.
     
  3. Chrispy

    Chrispy Pretentious Upstart

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    0.8mm to 1.1mm depending on plug and application.

    If they are iridium's or platinum's best not to regap them, you can damage them easily.
     
  4. Benny_C

    Benny_C About as subtle as...

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    1.1mm - 0.9mm
     
  5. Mitch

    Mitch Has one gear: GO

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    The gap is 1.1mm

    If you mean the GAP, then you are looking at the following plug types at the bottom:
    [​IMG]
     
  6. Mitch

    Mitch Has one gear: GO

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    TECH FORUM RUSH!!!!!
    4 responses in a space of 3 minutes. Nice :cool:
     
  7. Chrispy

    Chrispy Pretentious Upstart

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    Guess we all hate our jobs :p
     
  8. Benny_C

    Benny_C About as subtle as...

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    ^^ what he said ^^ :rofl:
     
  9. Mitch

    Mitch Has one gear: GO

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    E.O.I. for a Z related, technical job?
    Surely between the 3 of us a new business venture would be full of beer, shennanigans, and wacky engine transplants (v8's and otherwise).

    EDIT: why does E.O.I. without the full stops get edited as *** when the thread is submitted? that's weird... Anyone else have that problem?
     
  10. Benny_C

    Benny_C About as subtle as...

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    On topic: Mitch, i just gave you an innernets. Hope you like it bud. :br:
     
  11. rhy_boy1

    rhy_boy1 New Member

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    Thanks guys, these plugs are 4.4mm.... might tap them down a bit.

    We are all talking about this right?
    Just to be sure???

    ALSO:
    Thats 20 thousandths of an inch for you oldies. (I only had old tools :( )
    [​IMG]
     
  12. Chrispy

    Chrispy Pretentious Upstart

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    You are getting your conversions wrong. 40 thou is ~1mm.
     
  13. bRACKET

    bRACKET Do Right Dean

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    Whats the benefit to having correctly spaced plugs?
     
  14. Instamatic

    Instamatic Active Member

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    An engine that runs properly.
     
  15. bRACKET

    bRACKET Do Right Dean

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    Thanks for the sarcasm... How?
     
  16. rhy_boy1

    rhy_boy1 New Member

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    I'm pretty sure it has to do with the heat the plugs produce and a bigger/smaller spark.

    I'm really not sure ether, and dont expect a straight answer on the first go :p
     
  17. zedboy

    zedboy Active Member

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    all of the fuel mixture burns as good as it possibly can giving you an engine that works as best as it can.

     
  18. zenpython

    zenpython Von Yorp

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    what about these denso ones from the group buy what gap is needed for a stock TT
     
  19. Mitch

    Mitch Has one gear: GO

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    Correct Spark plug gap is needed for both performance and preventing mechanical engine damage (such as colision between the plug, valves and / or piston.
    Larger gap can make the spark blow out by excessive boost or supercharging. The ideal gap is determined by the compression ratio, and other factors such as how resilient the coil pack is at 'recharging' after an ignition event. With the z32, this is not really an issue, moreso in dizzie'd V8s with a single coil.

    In simple terms, the plug ignites the fuel, and initiates the flame front, which starts as a 'kernel' and spreads outwards from the propegation point.
    The reach of plug allows the flame front to propegate deeper into the combustion chamber, but as mentiond before, can be exposed to too much turbulence or impact from the rotating assembly.
    The flame front propegates at a relatively set speed, this is why spark advance increases with RPM.
     
  20. jschrauwen

    jschrauwen My Fairlady Z

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    NA - .044"
    TT - .035", higher HP TTZ's - .028"
     

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