Piston And Piston Pin

Check the piston and piston pin for damage, cracks or wear. Replace if faulty.
Check the piston ring groove for wear or damage. Replace if faulty.
Make sure the piston pin can be inserted into the piston pin hole by a thumb at 20°C (68°F). Replace if faulty.
Clearance between piston pin hole and piston pin:

Standard

0.004 - 0.008 mm (0.0002 - 0.0003 in)

Fig 1: Checking Clearance Between Piston Pin And Hole In Piston
Courtesy of SUBARU OF AMERICA, INC.

Fig 2: Checking Piston Pin
Courtesy of SUBARU OF AMERICA, INC.
Check the snap ring installation groove (A) on the piston for burr. If necessary, remove burr from the groove so that the piston pin can lightly move.

Fig 3: Identifying Snap Ring Installation Groove
Courtesy of SUBARU OF AMERICA, INC.
Check the piston pin snap ring for distortion, cracks and wear.