Block and Piston Inspection
Inspection1. Check the piston for distortion or cracks.
2. Measure the piston diameter at a point 16 mm (0.6 inch) 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):
No Letter (or A): 86.993 - 87.006 mm (3.4249 - 3.4254 inch)
B: 86.983 - 86.996 mm (3.4245 - 3.4250 inch)
Service Limit:
No Letter (or A): 86.980 mm (3.4244 inch)
B: 86.970 mm (3.4240 inch)
Oversize Piston Diameter: 0.25: 87.233 - 87.246 mm (3.4344 - 3.4349 inch)
3. 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 6 after reboring.
Cylinder Bore Size:
Standard (New):
A or I: 87.010 - 87.020 mm (3.4256 - 3.4260 inch)
B or II: 87.000 - 87.010 mm (3.4252 - 3.4256 inch)
Service Limit: 87.070 mm (3.4279 inch)
Oversize:
0.25: 87.250 - 87.260 mm (3.4350 - 3.4354 inch)
Reboring limit: 0.25 mm (0.01 inch) max.
Bore Taper:
Limit: (Difference between first and third measurement) 0.05 mm (0.002 inch)
4. Scored or scratched cylinder bores must be honed.
5. 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 inch) max.
Service Limit: 0.10 mm (0.004 inch)
6. 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 cylinder block for excessive wear.
Piston-to-Cylinder Clearance:
Standard (New): 0.004 - 0.027 mm (0.0002 - 0.0011 inch)
Service Limit: 0.04 mm (0.002 inch)