Repair Procedures: Inspection: Piston

1. Clean the piston.
   1. Using a gasket scraper, remove the carbon from the piston top.
   2. Using a groove cleaning tool or broken ring, clean the piston ring grooves.
   3. Using solvent and a brush, thoroughly clean the piston.
   NOTE:

   • Do not use a wire brush.
2. Check the piston-to-cylinder clearance by calculating the difference between the cylinder bore inner diameter and the piston outer diameter.

   Piston-To-Cylinder Clearance: 

   0.03 - 0.05 mm (0.0012 - 0.0020 in)

   1. Using a cylinder bore gauge, measure the cylinder bore diameter at position in the thrust and axial direction.

      Cylinder Bore Diameter: 

      77.00 - 77.03 mm (3.0315 - 3.0327 in)

   2. Measure the piston outside diameter at 12 mm (0.4724 in) from top land of the piston.

   Piston Outside Diameter: 

   76.96 - 76.99 mm (3.0299 - 3.0311 in)

3. Select the piston matching with cylinder bore class.

   Piston-To-Cylinder Clearance: 

   0.03 - 0.05 mm (0.0012 - 0.0020 in)

1. Check the cylinder bore size mark on the side of the cylinder block.

   Discrimination Of Cylinder Bore Size 

   Mark	Cylinder Bore Inner Diameter
   A	77.00 - 77.01 mm (3.0315 - 3.0319 in)
   B	77.01 - 77.02 mm (3.0319 - 3.0323 in)
   C	77.02 - 77.03 mm (3.0323 - 3.0327 in)

2. Check the piston size mark on the piston top face.

Piston Outer Diameter Difference