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 out of specification, 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 your thumb at 20°C (68°F). Replace if defective.
Standard clearance between piston pin and hole in piston:

Standard

0.004 - 0.008 mm (0.0002 - 0.0003 in)

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

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

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