Piston And Piston Pin

WARNING: This page is about a different car, the 2003 Subaru Outback, 2003 Subaru Legacy, and 2003 Subaru Baja. However, it is still accessible from the selected car via links, so may be relevant.

Check 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. See CYLINDER AND PISTON , INSPECTION, Cylinder Block. If any of the clearances is not to specification, replace the piston or bore the cylinder to use an oversize piston.
Make sure that piston pin can be inserted into the piston pin hole with a thumb at 20°C (68°F). Replace if defective.
Standard clearance between piston pin and hole in piston:
1. Standard: 0.004 - 0.008 mm (0.0002 - 0.0003 in)
2. Limit: 0.020 mm (0.0008 in)
Fig 1: Measuring Piston-To-Cylinder Clearance
Courtesy of SUBARU OF AMERICA, INC.

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

Fig 3: Removing Burr From Groove
Courtesy of SUBARU OF AMERICA, INC.
Check piston pin snap ring for distortion, cracks and wear.