FixVault

Boring Cylinder

  1. Oversize pistons used should be determined on the basis of the largest bore cylinder.
    Fig 1: Identifying Boring Cylinder
    G00320527Courtesy of KIA MOTORS AMERICA, INC.
    NOTE: Size mark is stamped on top of the piston.
  2. Measure the outside diameter of the piston to be used.
    Fig 2: Measuring Outside Diameter Of Piston
    G00320528Courtesy of KIA MOTORS AMERICA, INC.
  3. Based on the measured O.D., calculate the boring finish dimension.

    Boring finish dimension = piston outer diameter + 0.02~0.04 mm (The clearance between piston outer diameter and cylinder) - 0.01 mm (Honing margin).

  4. Bore each of the cylinders to the calculated size.
    CAUTION: To prevent distortion that may result from temperature rise during honing, bore the cylinder holes in the firing order sequence.
  5. Hone the cylinders, finishing them to the proper dimension (piston outside diameter + gap with cylinder).
  6. Check the clearance between the piston and cylinder.

    Standard value: 0.03-0.05 mm

    (0.0012 - 0.0020 in)

    NOTE:
    • Cylinders should be bored to the same oversize.
    • Never bore only one cylinder to an oversize.