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  1. #1
    actis's Avatar
    Join Date
    Mar 2013
    maryland and florida

    is a .125 bore unusual?

    i have my 2005 4tec scic engine in the machine shop for bore and hone. i recently purchased the block and crank on ebay. the machinest said i'll probably need a oversized piston over 100. some rust on the cylinder wall had to be removed and he believes boring it to 100.125 over standard should clean it out. my question is. isn't that a large bore for this motor? i just have a hard time believing this motor has been bored out that much. unless it suffered a major cylinder wall injury. most of the pistons i have seen are .22, .25, .50 over standard. whats the most these engines can be bored before they need to be sleeved? i spoke to a rep. at torx and he said .125 is a common size for these engines. any insight would be appreciated. BTW the crank polished up fine and is still standard on mains and rods.
    Last edited by actis; 03-21-2013 at 10:47 PM. Reason: MISTYPED BORE SIZE

  2. #2
    Got Boost? psycho rxp's Avatar
    Join Date
    Jul 2005
    Port St. Lucie, FL
    Riva pistons measure 100.19mm for .10 over, and 100.44mm for .20 over.
    They tens to run just a touch smaller than the CP's do. It depends on what size your machinist says it needs to go to, on which size/brand piston u will need.

    I'm doing the Same thing on my bore now. Its getting bored to 100.25mm to clear up some rust from water laying in the cyl.
    My old block Ran the 100.44mm bore for over 2 yrs @ 9,000 + rpms

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