Engine Block and Piston Inspection

1.Remove the crankshaft and pistons.

2.Check the piston for distortion or cracks.

3.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): 
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.)

Service Limit: 
No Letter (or A): 85.930 mm (3.3831 in.) 
B: 85.920 mm (3.3827 in.) 

Oversize Piston Diameter 
0.25: 86.230-86.240 mm (3.3949-3.3953 in.) 



4.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 block. If the block is being rebored, refer to 7 after reboring.

Cylinder Bore Size 
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.) 

0.25: 86.250-86.260 mm (3.3957-3.3961 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.) 


5.Scored or scratched cylinder bores must be honed.

6.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.) 



7.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-to-Cylinder Bore Clearance
Standard (New): 0.020-0.040 mm
(0.0008-0.0016 in.)
Service Limit: 0.05 mm (0.002 in.)