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Safe to bore F22B block to 85.5mm? also perfect hone for forged pistons?

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    #1

    Safe to bore F22B block to 85.5mm? also perfect hone for forged pistons?

    Hey guys im thinking of buying a block that has been over-honed for regular pistons, however i have forged pistons and they expand more, what is the perfect hone for forged pistons, the block is f22b with 50,00-miles.

    Also is it safe to bore out this f22b block to 85.5mm? this is what i would like to do idealy i think its better then just hone, however im gonna be shooting for 400whp and need to know if its really "safe" to bore it out at this much power.

    thanks
    1991 Accord LX Coupe - Boosted F22 - 5spd LSD - Shaved Bay - Work VSXX - Recaro SRD

    Member's Ride Page | Video of my CB7, Open Downpipe peelout
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    #2
    Block he is referring to is mine :P

    Since my stock style/ cast hypereutectics are out of spec for piston to wall clearance... range from .0035 - .0045. When service limit is .002.

    however as ILBB stated in my thread... (http://www.cb7tuner.com/vbb/showthread.php?t=61408) , recommended for forged pistons is .004-.006 due to the expansion of forged pistons.

    So A) he could have my block professionally honed to the exact recommended clearance (and take any unevenness out, If there is any, for a perfectly true cylinder)...also wouldnt' hurt to have it honed with flexplate on.

    B) it could be bored over to 85.5...but i have no idea how that will affect the strength when trying to push the sleaves to their limits.

    C) he could use his current block with 120k Miles and have it honed to proper spec, But i'm giving him my Eagle H-beam rods for the switch (plus getting a tranny as well)

    Anyone who has decent knowledge of engine building here can pipe up.

    Mark

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      #3
      I heard also that forged pistons that are standard size, have rings that are smaller then the stock ones, forged pistons that are standard size are made to work with a stock block, no honing at all, and that honing it to 0.005 when using std size forged pistons is not a good idea. I need some opinions on this one, i think im just gonna bore it out a tiny bit, hope its safe tho.
      1991 Accord LX Coupe - Boosted F22 - 5spd LSD - Shaved Bay - Work VSXX - Recaro SRD

      Member's Ride Page | Video of my CB7, Open Downpipe peelout

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        #4
        I'm pretty sure the ring size will not be affected by anything and a .005 over (if that) would not make much if any difference on the end gap...usually the end gaps need to be filed and changed anyways.

        ANyways, you could be right about the forged being made to work with stock bored pistons. I wonder however if since you're getting custom pistons if you could get them at even less than 85.5mm, like 85.25mm. Just a thought.

        Hopefully we can get some second opinions here. (but my best bet would be to just bore to 85.5).

        Mark

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