Piston and Connecting Rod Assemble

Special Tools 

EN-46745  Piston Pin Retainer Remover and Installer

For equivalent regional tools, refer to Special Tools .

Fig 1: Locating "Cast Boss" On Underside of Piston
Courtesy of GENERAL MOTORS COMPANY
NOTE:

Install the piston onto the connecting rod with the arrow on top of the piston toward the front oriented toward the front of the engine.

NOTE:

The cast boss (1) can be in either or both locations depending on displacement.

1. The cast boss (1), on the underside of the piston, must go to the rear of the block.
Fig 2: Identifying Cast Mark
Courtesy of GENERAL MOTORS COMPANY
2. The larger feature (1), at the split line located on one side of the connecting rod, must go to the front of the block.
Fig 3: View of Connecting Rod and Piston
Courtesy of GENERAL MOTORS COMPANY
3. Assemble the connecting rod (2) and the piston (1).
Fig 4: View of Piston Pin Retainers
Courtesy of GENERAL MOTORS COMPANY
CAUTION:

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  installer. 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  installer (1) .
   5. Ensure that the piston moves freely.
Fig 5: Identifying Piston Rings
Courtesy of GENERAL MOTORS COMPANY
CAUTION:

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 (5)
   2. The lower oil control ring (4)
   3. The upper control ring (3)
6. Install the lower compression ring (2). Place the manufacturer's mark facing up.
7. Install the upper compression ring (1).