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  1. #1
    isa alnoaimi's Avatar
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    WISECO forged piston clearance help ?

    hi everyone

    im rebuilding my 255 engine jet boat , what clearances do i have to go with ?

    wiseco manual says 0.0019 which i think is very tight !!!

    thanks in advance !!!
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  2. #2
    ptscon's Avatar
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    0.004 is a safe bet, it's what I run.

  3. #3
    isa alnoaimi's Avatar
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    Quote Originally Posted by ptscon View Post
    0.004 is a safe bet, it's what I run.
    first ring gap?

    second ring gap ?

  4. #4
    ptscon's Avatar
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    Top: 0.023
    Bot: 0.028

    What I currently run, it's skewed a bit towards larger gap aka safer.

  5. #5
    isa alnoaimi's Avatar
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    Quote Originally Posted by ptscon View Post
    Top: 0.023
    Bot: 0.028

    What I currently run, it's skewed a bit towards larger gap aka safer.

    what boost you running ?

    thanks for your help buddy

  6. #6
    ptscon's Avatar
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    Quote Originally Posted by isa alnoaimi View Post
    what boost you running ?

    thanks for your help buddy

    I run 300 charger et135 so about 17-18 psi at 8900 RPM.

  7. #7
    isa alnoaimi's Avatar
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    Quote Originally Posted by ptscon View Post
    I run 300 charger et135 so about 17-18 psi at 8900 RPM.

    woow impressive

    what year ski ? what did you modify to install the 300 super charger ?

    im thinking of doing it too to my jet boat engine .

  8. #8
    isa alnoaimi's Avatar
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    this riva racing pistons instructions , i believe these are CP pistons .
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  9. #9
    ptscon's Avatar
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    Quote Originally Posted by isa alnoaimi View Post
    woow impressive

    what year ski ? what did you modify to install the 300 super charger ?

    im thinking of doing it too to my jet boat engine .

    2012 RXP 260, you need to replace the flywheel with one from 300 and have the PTO housing modified for oil return port.


    Quote Originally Posted by isa alnoaimi View Post
    this riva racing pistons instructions , i believe these are CP pistons .

    If you look closely those numbers are not the final ring end gap, it's a multiplication factor. So bore size, in inches, multiplied by 0.008 for example.

  10. #10
    tiderider's Avatar
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    Quote Originally Posted by ptscon View Post
    0.004 is a safe bet, it's what I run.
    How many hours have you put on your Wiseco piston set up?

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