Piston And Piston Pin

WARNING: This page is about a different variant/trim than selected.

Check the pistons and piston pins for damage, cracks and wear, and the piston ring grooves for wear and damage. Replace if defective.
Measure the piston-to-cylinder clearance at each cylinder. < Ref. to , CYLINDER AND PISTON, INSPECTION , Cylinder Block.> If any of the clearances is not within the standard value, replace the piston. Or bore the cylinder to use an oversize piston.
Make sure that the piston pin can be inserted into the piston pin hole with a thumb at 20°C (68°F). Replace if defective.
Clearance between piston hole and piston pin:

Standard

0.004 - 0.008 mm (0.0002 - 0.0003 in)

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

Fig 2: Measuring Diameter 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: Locating Snap Ring Installation Groove
Courtesy of SUBARU OF AMERICA, INC.
Check the piston pin snap ring for distortion, cracks and wear.