Piston Pin & Connecting Rod Bushing

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

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 With Micrometer
  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 bushing and piston pin as a set. For replacement procedure of connecting rod bushing, refer to the following.
1. Using the ST and a press, pull out the connecting rod bushing from the small end of the connecting rod.
  NOTE: The direction of ST for pulling out and for press fitting is different. Therefore, attention must be paid to the direction of usage for ST.
  
  ST 18350AA000 CONNECTING ROD BUSHING REMOVER AND INSTALLER
  
  Fig 3: Pulling Out Connecting Rod Bushing From Small End Of Connecting Rod
  Courtesy of SUBARU OF AMERICA, INC.
2. Press the connecting rod bushing with ST and the press, after applying engine oil on the periphery of connecting rod bushing.
  NOTE:
  - Clinch area of the connecting rod bushing is as shown in the figure.
    
    Fig 4: Clinch Area Of Connecting Rod Bushing
    Courtesy of SUBARU OF AMERICA, INC.
  - The direction of ST for pulling out and for press fitting is different. Therefore, attention must be paid to the direction of usage for ST.
  ST 18350AA000 CONNECTING ROD BUSHING REMOVER AND INSTALLER
  
  Fig 5: Pulling Out Connecting Rod Bushing
  Courtesy of SUBARU OF AMERICA, INC.
3. Make two 3 mm (0.12 in) holes in the pressed connecting rod bushing by aligning with the pre-manufactured holes provided on the small end of the connecting rod.
4. Using a reamer, ream the inside surface of the connecting rod bushing. Insert the reamer in the connecting rod bushing, and turn slowly clockwise while pushing lightly. Bring the reamer back while rotating it clockwise.
  NOTE:
  - Use a reamer with a diameter of □22.
  - Apply engine oil to the reamer.
  - If the inner surface of connecting rod bushing is damaged, the edge of reamer should be slightly ground with oil stone.
  - If the inner surface of connecting rod bushing becomes lustrous and the reamer does not chip, use a new reamer or remedy the reamer.
5. After completion of reaming, clean the connecting rod bushing to remove chips.