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SERIES 638 PISTON AND CONNECTING ROD

The piston and connecting rod assembly are one unit made of two separate components. ‪

For piston and piston ring information, refer to section . ‪

For connecting rod information, refer to section . ‪

Repair or Replacement of Piston and Connecting Rod

To determine if repair or replacement of the piston and connecting rod is necessary, perform the following procedure. See Figure 21779 . ‪

Flowchart for Repair or Replacement of Piston and Connecting Rod

Removal of Piston and Connecting Rod

Remove the piston and connecting rod as follows: ‪

  1. Remove cylinder head. Refer to section .
  2. Remove the oil pan. Refer to section .
  3. Remove oil pickup tube assembly. Refer to section .
  4. Remove two hex head flange bolts from the connecting rod assembly. Repeat step for each connecting rod assembly.
  5. Remove the piston and connecting rod from the cylinder block. Repeat step for each piston and connecting rod.

    Note: Mark the connecting rod assembly to designate cylinder position.

Cleaning of Piston and Connecting Rod

Clean the piston and connecting rod as follows: ‪

  1. Remove any dirt or debris from the piston and connecting rod using clean fuel oil.

    To avoid personal injury when blow drying, wear adequate eye protection (safety glasses or face plate) and do not exceed 276 kPa (40 lb/in. 2 ) air pressure. ‪

  2. Dry the piston and connecting rod with compressed air.
Inspection of Piston and Connecting Rod

Inspect the piston and connecting rod as follows: ‪

  1. Visually check piston components for damage.
    1. If the piston components are damaged, replace the components. Refer to section .
    2. If the piston components are not damaged, reuse the components. Proceed with step of inspection.
  2. Visually check connecting rod components for damage.
    1. If the connecting rod components are damaged, replace the components. Refer to section .
    2. If the connecting rod components are not damaged, proceed with step of inspection.
  3. Visually check the cylinder liners for damage.
    1. If the cylinder liners are damaged, replace the components. Refer to section .
    2. If the cylinder liners are not damaged, reuse the components. Refer to section .

Installation of Piston and Connecting Rod

Install the piston and connecting rod as follows: ‪

  1. Using a ring compressor, install the piston and connecting rod into the cylinder block. Repeat step for each piston and connecting rod.

    Note: Ensure the cylinder liner is clean prior to installation.

    Note: Apply a light coating of Molyguard to the bolts prior to installation.

  2. Install two hex head flange bolts to the connecting rod. Repeat step for each connecting rod. Torque bolts to 29-30 N m (21-22 lb ft) plus a 605 torque turn (using torque angle gauge VM 1005).
  3. Install oil pickup tube assembly. Refer to section .
  4. Install oil pan. Refer to section .
  5. Install cylinder head(s). Refer to section .
  6. Run engine to verify repairs.