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Block & Piston Inspection

  1. Remove the piston from the cylinder block (see Crankshaft & Piston Removal  ).
  2. Check the piston for distortion or cracks.
  3. Measure the piston diameter at a point 16.0 mm (0.63 in.) from the bottom of the skirt.

    Piston Diameter 

    Standard (New):  88.975-88.985 mm (3.5029-3.5033 in.)

    Service Limit:  88.965 mm (3.5026 in.)

    Oversize Piston Diameter 

    0.25:  89.225-89.235 mm (3.5128-3.5132 in.)

    0.50:  89.475-89.485 mm (3.5226-3.5230 in.)

    Fig 1: Measuring Piston Diameter
    G01463815Courtesy of AMERICAN HONDA MOTOR CO., INC.
  4. Measure wear and taper in directions X and Y at three levels in each cylinder as shown.
    • If the bore size or taper in any cylinder is over the service limit, the block must be rebored.
    • If the measurements in any cylinder are beyond the oversize bore service bore service limit, replace the cylinder block.
    Fig 2: Measuring Wear & Taper
    G01463816Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Cylinder Bore Size 

    Standard (New):  89.000-89.015 mm (3.5039-3.5045 in.)

    Service Limit:  89.065 mm (3.5065 in)

    Oversize 

    0.25:  89.250-89.265 mm (3.5138-3.5144 in.)

    0.50:  89.500-89.515 mm (3.5236-3.5242 in.)

    Reboring Limit:  0.5 mm (0.02 in.)

    Bore Taper 

    Limit:  (Difference between first and third measurement) 0.05 mm (0.002 in.)

  5. Scored or scratched cylinder bores must be honed.
  6. Check the top of the cylinder block for warpage. Measure along the edges and across the center as shown.

    Cylinder Block Warpage 

    Standard (New):  0.07 mm (0.003 in.) max.

    Service Limit:  0.10 mm (0.004 in.)

    Fig 3: Checking The Top Of The Cylinder Block For Warpage
    G01463817Courtesy of AMERICAN HONDA MOTOR CO., INC.
  7. Calculate the difference between cylinder bore diameter and piston diameter. If the clearance is near or exceeds the service limit, inspect the piston and cylinder block for excessive wear.

    Piston-to-Block Clearance 

    Standard (New):  0.015-0.040 mm (0.0006-0.0016 in.)

    Service Limit:  0.08 mm (0.003 in.)

    Fig 4: Measuring Piston-To-Block Clearance
    G01463818Courtesy of AMERICAN HONDA MOTOR CO., INC.