Tools Required

EN-46745  Piston Pin Retainer Remover and Installer

Fig 1: Locating "Cast Boss" On Underside of Piston
Courtesy of GENERAL MOTORS CORP.
IMPORTANT: Install the piston onto the connecting rod with the arrow oriented toward the front of the engine.
1. The cast boss (1), on the underside of the piston, must go to the rear of the block.
Fig 2: Identifying Cast Boss
Courtesy of GENERAL MOTORS CORP.
2. The cast mark (1), on the connecting rod, must go to the front of the block.
Fig 3: Assembling Connecting Rod & Piston
Courtesy of GENERAL MOTORS CORP.
3. Assemble the connecting rod and the piston.
Fig 4: Identifying Piston Pin Retainer Tool
Courtesy of GENERAL MOTORS CORP.
NOTE: Install the piston pin retainers correctly in the retaining groove during assembly in order to avoid engine damage.
4. Use the following procedure to assemble the piston pin and the retainer:
   1. Coat the piston pin with oil.
   2. Install one side of one piston pin retainer into the retaining groove using EN-46745  . Rotate the retainer until it is fully seated in the groove.
   3. Install the connecting rod and the piston pin.

      Push the piston pin until it bottoms in the previously installed retainer.

   4. Install the second piston pin retainer, using EN-46745  .
   5. Ensure that the piston moves freely.
Fig 5: Exploded View Of Piston Rings
Courtesy of GENERAL MOTORS CORP.
NOTE: Use a piston ring expander to install the piston rings. The rings may be damaged if expanded more than necessary.
5. Install the following components of the oil control ring assembly (bottom ring):
   1. The expander
   2. The lower oil control ring
   3. The upper control ring
6. Install the lower compression ring (second ring). Place the manufacturer's mark facing up.
7. Install the upper compression ring (top ring).