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: 

   0.035 - 0.055 mm (0.0014 - 0.0022 in.)

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

      Cylinder bore diameter: 

      75.60 - 75.63 mm (2.9764 - 2.9776 in.)

      Courtesy of HYUNDAI MOTOR AMERICA

   2. Measure the piston outside diameter at 13.0 mm (0.5118 in.) from top land of the piston.

   Piston outside diameter: 

   75.555 - 75.585 mm (2.9746 - 2.9758 in.)

   Courtesy of HYUNDAI MOTOR AMERICA

3. Select the piston matching with cylinder bore class. (match classification mark)

Piston-to-cylinder clearance: 

0.035 - 0.055 mm (0.0014 - 0.0022 in.)

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

   Courtesy of HYUNDAI MOTOR AMERICA

   Discrimination of Cylinder Bore Size 

   Class	Mark	Cylinder bore inner diameter
   a	A	75.60 - 75.61 mm (2.9764 - 2.9768 in.)
   b	B	75.61 - 75.62 mm (2.9768 - 2.9772 in.)
   c	C	75.62 - 75.63 mm (2.9772 - 2.9776 in.)

2. Check the piston outer diameter size mark (A) on the piston top face.

Courtesy of HYUNDAI MOTOR AMERICA

A: GRADE MARK

M: MPI

6: 1.6L

Discrimination of Piston Outer Diameter