Discussion in ''Da Nailhead' started by mark fox, Sep 3, 2018.

  1. mark fox

    mark fox New Member

    I am reconditioning a 401 nailhead and wondering what the tolerances are for the rods. The rod bearings seem nice and tight and the shortblock assembly turns just fine. But there is a little bit of play fron side to side on all of them is that normal?
  2. telriv

    telriv Well-Known Member

    Rod side clearance for BOTH rods on crankpin .005"-.012"
    300sbb_overkill likes this.
  3. Stevem

    Stevem Well-Known Member

    What do you mean by reconditioning?
    Are you just installing new Bearings, or checking the Bearings and replacing ones the show ware?
    If so what brand Bearings will you be using?
    In terms of both rod and main Bearing clearance .0015" .0018 "is great, but any thing over .002" for a street only motor needs to get the Crank cut in my book!
    You can tell how well sized and round the rod big end Bores and the Crank main Bores still are by the inpression of the part number on the rear of the Bearings that is left in these Bores.

    Unclear impressions mean that the much needed Bearing crush was not what it should be and the Bearing was moving!
  4. Schurkey

    Schurkey Silver Level contributor

    Are you confusing "tolerances" for "clearances"?

    Some side-clearance is essential.

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