Engine Block and Piston Inspection

  1. Check the piston for distortion or cracks.
  1. Measure the piston diameter at a point 13 mm (0.5 in.) from the bottom of the skirt. There are two standard-size pistons (No Letter or A, and B). The letter is stamped on the top of the piston. Letters are also stamped on the engine block as the cylinder bore sizes.
    Piston Skirt Diameter
    Standard (New):
    No Letter (or A):
    86.980−86.990 mm (3.4244−3.4248 in.)
    B:
    86.970−86.980 mm (3.4240−3.4244 in.)
    Service Limit:
    No Letter (or A):
    86.930 mm (3.4224 in.)
    B:
    86.920 mm (3.4220 in.)


    Oversize Piston Skirt Diameter
    0.25:
    87.230−87.240 mm (3.4342−3.4346 in.)


  1. Measure the wear and taper in direction X and Y at three levels inside each cylinder as shown. If the measurements in any cylinder are beyond the Oversize Bore Service Limit, replace the engine block. If the engine block is being rebored, refer to Step 7 after reboring.
    Cylinder Bore Size
    Standard (New):
    A or I:
    87.010−87.020 mm (3.4256−3.4260 in.)
    B or II:
    87.000−87.010 mm (3.4252−3.4256 in.)
    Service Limit:
    87.070 mm (3.4279 in.)

    Oversize Bore
    0.25:
    87.250−87.260 mm (3.4350−3.4354 in.)

    Reboring Limit:
    0.25 mm (0.01 in.) max.

    Bore Taper
    Limit (Difference between first and third measurement):
    0.02 mm (0.0008 in.)

  1. Scored or scratched cylinder bores must be honed.

  1. Check the top of the engine block for warpage. Measure along the edges and across the center as shown.
    Engine Block Warpage
    Standard (New):
    0.07 mm (0.003 in.) max.
    Service Limit:
    0.10 mm (0.004 in.)


  1. Calculate the difference between the cylinder bore diameter and the piston diameter. If the clearance is near or exceeds the service limit, inspect the piston and the cylinder bore for excessive wear.
    Piston-to-Cylinder Bore Clearance
    Standard (New):
    0.020−0.040 mm (0.0008−0.0016 in.)
    Service Limit:
    0.05 mm (0.002 in.)