Block and Piston Inspection
- Remove the crankshaft and the pistons (see CRANKSHAFT AND PISTON REMOVAL )
- Check the piston for distortion or cracks
- 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
- 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
- Scored or scratched cylinder bores must be honed
- Check the top of the engine block for warpage Measure along the edges and across the center as shown
- 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 bore for excessive wear
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)
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 05 mm (0 002 in)
Engine Block Warpage
Standard (New). 0 07 mm (0 003 in) max
Service Limit 0 10 mm (0 004 in)
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)