GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 24086-C Piston Pin Removal and Installation Set

    Important: Each connecting rod and connecting rod bearing cap must be marked, beginning at the front of the engine. When viewed from the front of the engine, cylinders 1, 3, 5, and 7 are the right bank. Cylinders 2, 4, 6, and 8 are the left bank. The numbers on the connecting and the bearing cap must be on the same side when installed in the cylinder bore. If a connecting rod is ever transposed from one block or cylinder to another, the new connecting rod bearings must be fitted and the connecting rods renumbered in order to correspond with the new cylinder number. The connecting rod is not symmetrical and the outside always faces the outside.


    Object Number: 66630  Size: SH
  1. Assemble the piston and the connecting rod as follows:
  2. 1.1. Ensure that the alignment mark on the top of the piston faces the front of the engine block. The connecting rod must be installed in the correct orientation.
    1.2. Lubricate the piston pin holes in the piston and the connecting rod with engine oil.
    1.3. Install the pin guide.

    Hold the piston and the connecting rod together. Use the proper pin guide and refer to the manufacturer's instructions for proper use.


    Object Number: 4978  Size: SH
  3. Install the piston pin as follows:
  4. 2.1. Insert the piston pin into the piston pin hole.
    2.2. Place the assembly on the J 24086-C .
    2.3. Adjust the piston pin installer to the correct length, using the letter-number scale on the installer adjuster.

    Ensure the piston pin is pressed into the correct depth. Refer to the manufacturer's instructions supplied with the tool for the proper setting.

    2.4. Lock the adjuster in place with the lock ring.

            Notice: After the J 24086-C installer hub bottoms on the support assembly, DO NOT exceed 35,000 kPa (5,000 psi) or the tool may be damaged.

    2.5. Place the adjuster in the J 24086-C .
    2.6. Press the piston pin into place until the adjustable installer bottoms in the J 24086-C .
    2.7. Remove the piston and the connecting rod assembly from the J 24086-C .

    Check the piston for freedom of movement on the piston pin.

Piston Rings Installation Procedure


    Object Number: 4968  Size: SH
  1. Measure the ring end gap as follows:
  2. 1.1. Select the rings comparable in size to the piston being used.
    1.2. Slip the compression ring into the cylinder bore.
    1.3. Use the piston to square ring in the cylinder wall.

    Insert the piston without rings upside down and guide the compression ring into the cylinder bore until the ring is down about 38 mm (1.499 in) below the ring travel.

    1.4. Measure the gap between the ends of the ring with a feeler gauge. Refer to Engine Mechanical Specifications .
    1.5. If the gap between the ends of the ring is not as specified, remove the ring and try another for fit.

    Object Number: 4969  Size: SH
  3. Inspect the ring fit as follows:
  4. 2.1. Fit each compression ring to the piston on which the compression ring is to be used.
    2.2. Slip the outer surface of the top and the second compression ring into the respective piston ring groove in order to ensure that the compression ring is free.
    2.3. If binding occurs at any point, determine the cause.
    2.4. If binding is caused by the ring groove, correct it by dressing the groove with a fine cut file.
    2.5. If the binding is caused by a distorted ring, try a new ring.

    Important: All compression rings are marked on the upper side of the ring.

    When installing the compression rings, ensure that the marked side is toward the top of the piston.

    The oil rings are 3-piece assemblies, consisting of two rails and an expander.


    Object Number: 4977  Size: SH
  5. Assemble the piston rings in the following order:
  6. 3.1. The expander
    3.2. The lower rail
    3.3. The upper rail
    3.4. The lower compression ring
    3.5. The upper compression ring
  7. Flex all of the rings in order to ensure that the rings are free.
  8. Determine the cause of any binding.
  9. If binding is caused by the ring groove, correct the binding by dressing the groove with a fine cut file.
  10. If the binding is caused by a distorted ring, try a new ring.
  11. • Rings gaps must be 180 degrees apart.
    • Rail gaps must be 180 degrees apart.

    Object Number: 22934  Size: SH
  12. Use the feeler gauge in order to measure ring to land clearance.