Block and Piston Inspection (L12A/L13A)

Block and Piston Inspection

1.Remove the crankshaft and pistons.

2.Check the piston for distortion or cracks.

3.Measure the piston diameter (A) at a point 13 mm (0.5 in.) from the bottom of the skirt.

Piston Diameter:
Standard (New): 72.98-72.99 mm
(2.8732-2.8736 in.)
Service Limit: 72.97 mm
(2.8728 in.)


Oversize Piston Diameter:
0.25: 73.23-73.24 mm (2.8831-2.8835 in.) 

4.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 7 after reboring.

Cylinder Bore Size:
Standard (New): 73.00-73.02 mm
(2.8740-2.8748 in.)
Service Limit: 73.07 mm (2.8767 in.) 

0.25: 73.25-73.27 mm (2.8839-2.8846 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 block for excessive wear.

Piston-to-Cylinder Clearance:
Standard (New): 0.010-0.040 mm
(0.0004-0.0016 in.)
Service Limit: 0.05 mm (0.002 in.)