Piston Pin & Connecting Rod Bushing

Check that the connecting rod bushing is not damaged.
Check the clearance between piston pin and connecting rod bushing. Check the clearance between piston pin and connecting rod bushing by measuring the outer diameter of piston pin and the inner diameter of connecting rod bushing respectively.
1. Measure the outer diameter of piston pin with a micrometer.
  NOTE:
  - Measurement should be performed at a temperature of 20°C (68°F).
  - Measure the outer diameter of the piston pin at the two locations as shown in the figure, and read the value of most worn location.
  - Record the measured value.
  Fig 1: Measuring Outer Diameter Of Piston Pin
  Courtesy of SUBARU OF AMERICA, INC.
2. Using a caliper gauge, measure the inner diameter of connecting rod bushing.
  NOTE:
  - Measurement should be performed at a temperature of 20°C (68°F).
  - Measure the inner diameter of the connecting rod bushing at the two locations as shown in the figure, and read the value of most worn location.
  - Record the measured value.
  Fig 2: Measuring Inner Diameter Of Connecting Rod Bushing
  Courtesy of SUBARU OF AMERICA, INC.
3. Calculate the clearance between piston pin and connecting rod bushing.
Clearance between piston pin and connecting rod bushing:

Standard

0.004 - 0.026 mm (0.0002 - 0.0010 in)
If the clearance between piston pin and connecting rod bushing is not within the standard, replace the connecting rod and piston pin as a set.