Engine Block and Piston Inspection

1. Remove the crankshaft and pistons. Check the piston for distortion or cracks. Measure the piston diameter at a point 11 mm (0.4 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 block as cylinder bore sizes. Piston Diameter
   Standard (New):
   K20Z2 Engine:
   No Letter (or A): | 85.980−85.990 mm (3.3850−3.3854 in.)
   B: | 85.970−85.980 mm (3.3846−3.3850 in.)
   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.)
   No Letter (or A): | 85.930 mm (3.3831 in.)
   B: | 85.920 mm (3.3827 in.)
   No Letter (or A): | 86.930 mm (3.4224 in.)
   B: | 86.920 mm (3.4220 in.)
   Oversize Piston Diameter
   K20Z2 Engine:
   0.25: | 86.230−86.240 mm (3.3949−3.3953 in.)
   0.25: | 87.230−87.240 mm (3.4342−3.4346 in.)

1. Measure wear and taper in direction X and Y at three levels in each cylinder as shown. If measurements in any cylinder are beyond the Oversize Bore Service Limit, replace the block. If the block is to be rebored, refer to Step 7 after reboring. Cylinder Bore Size
   K20Z2 Engine:
   Standard (New):
   A or I: | 86.010−86.020 mm (3.3862−3.3866 in.)
   B or II: | 86.000−86.010 mm (3.3858−3.3862 in.)
   Service Limit: | 86.070 mm (3.3886 in.)
   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
   K20Z2 Engine:
   0.25: | 86.250−86.260 mm (3.3957−3.3961 in.)
   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) 0.05 mm (0.002 in.)
Scored or scratched cylinder bores must be honed. |

1. Check the top of the 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 engine block 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.)