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Thread: Piston Ring gaps

  1. #1
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    Piston Ring gaps

    I'm gapping my Hastings (2C4670) rings and thought I'd ask here before I wreck this set. Ross pistons + 040. Got a tip from a performance guy locally who suggested I calculate gap using cyl bore x .0080 for the top ring and multiply that result by 1.5 for the second ring.

    So 92.0mm x 0.0080 = 0.736mm (0.029") for top ring and 1.10mm (0.044") for the second.

    I've seen reference to that to ring formula on one Hastings tech article but can't find anything on the second ring although I have seen other references indicating to add 0.0005 to the calc factor for the second ring (so 0.0085).

    Does anyone here have some solid help and guidance to offer?

    Des
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    Des
    Grande Prairie, AB

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    Most of those gap calculates are the bore in inches times your ratio. Those gaps you gave are therefore quite excessive. Your 2nd ring gap is about twice too large.

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    Edit: nevermind... I see what you did..

    That's way too wide though... I'd put the top ring in the low 20's and the second ring a couple thou bigger.
    Last edited by RealMcCoy; 07-15-2012 at 02:05 PM.


    Real Performance Automotive (541)816-4500 www.FB.com/RealPerformanceAuto

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    Quote Originally Posted by Forest Gump View Post
    Most of those gap calculates are the bore in inches times your ratio. Those gaps you gave are therefore quite excessive. Your 2nd ring gap is about twice too large...
    Quote Originally Posted by RealMcCoy View Post
    ...That's way too wide though... I'd put the top ring in the low 20's and the second ring a couple thou bigger.
    Thx very much, I appreciate the help and confirmation and really helps me a lot.

    Des
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    Quote Originally Posted by RealMcCoy View Post
    Edit: nevermind... I see what you did..

    That's way too wide though... I'd put the top ring in the low 20's and the second ring a couple thou bigger.
    About what I set mine to. Runs good. Still only ~500 miles on her though.

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