Piston and Connecting Rod Assemble

Special Tools 

EN-49941  Remover/Installer Piston Retainer Ring

For equivalent regional tools, refer to Special Tools .

1. Install the connecting rod (3) and the piston pin (2) to the piston (1).
   Fig 1: Connecting Rod, Piston And Piston Pin

   Courtesy of GENERAL MOTORS COMPANY
   NOTE: Lubricate the piston pin with clean engine oil.
2. Install the piston and connecting rod assembly to a bench vise. Use aluminum braces.
3. Place the piston pin retainer in the piston pin retainer groove so that the ring gap lays on the notch (2).
   Fig 2: Pushing Piston Pin Retainer Down With Thumb

   Courtesy of GENERAL MOTORS COMPANY
   WARNING: Use extreme care when removing snap rings. Always wear adequate eye protection in order to avoid personal injury.
   WARNING: Use care when removing or installing the piston retainer ring. Ensure the EN-49941 remover/installer is installed properly onto the retainer ring and that hands and fingers are kept clear from the front of the tool. Otherwise, bodily injury may occur.
   NOTE: Notch (2) on right side.
4. Push the piston pin retainer down with the thumb in the shown position (1) and hold.
5. Apply the EN-49941  installer (4) to the piston pin retainer in the position shown (3) and push in direction of the arrow while pushing down with the thumb.
   NOTE: The EN-49941  installer should be applied in a perpendicular position to the piston pin retainer.
6. Move the EN-49941  installer (1) carefully to the position shown while pushing in direction of the arrow until the piston pin retainer engages in the piston pin retainer groove.
   Fig 3: Pushing Piston Pin Retainer Down

   Courtesy of GENERAL MOTORS COMPANY
   NOTE: Push the piston pin retainer down in the position shown (2).
7. Push down the piston ring retainer to get a proper seat in the groove.
8. Place the piston pin retainer in the piston pin retainer groove so that the ring gap lays on the notch (4).
   Fig 4: Pushing Piston Pin Retainer Down With Thumb

   Courtesy of GENERAL MOTORS COMPANY
   NOTE: Notch (4) on left side. EN-49941  installer should be used with left hand.
9. Push the piston pin retainer down with the thumb in the position shown (1) and hold.
10. Apply the EN-49941  installer (3) to the piston pin retainer in the position shown (2) and push in direction of the arrow while pushing down with the thumb.
    NOTE: The EN-49941  installer should be applied in a perpendicular position to the piston pin retainer.
11. Move the EN-49941  installer (2) carefully to the position shown while pushing in direction of the arrow until the piston pin retainer engages in the piston pin retainer groove.
    Fig 5: Pushing Piston Pin Retainer Down

    Courtesy of GENERAL MOTORS COMPANY
    NOTE: Push the piston pin retainer down in the position shown (1).
12. Push down the piston ring retainer to get a proper seat in the groove.
13. Remove the piston and connecting rod assembly from the bench vise.
14. Install the piston rings. Use piston ring pliers (1).
    Fig 6: Using Piston Ring Pliers

    Courtesy of GENERAL MOTORS COMPANY
15. The piston rings must be ordered as followed:
    Fig 7: Upper Compression Ring, Lower Compression Ring, Oil Rings And Oil Ring Spacer

    Courtesy of GENERAL MOTORS COMPANY
    NOTE: Mind the TOP marking on the piston rings.
    • Upper compression ring (1)
    • Lower compression ring (2)
    • Piston oil ring with spacer (3), (4)
16. The piston ring joints must be positioned 90 degrees to each other.
    Fig 8: Oil Ring Joints, Lower Compression Ring Joint, Upper Compression Ring Joint And Oil Ring Spacer Joint

    Courtesy of GENERAL MOTORS COMPANY
    • Upper compression ring joint (2)
    • Lower compression ring joint (5)
    • Oil ring joint, upper part (1)
    • Oil ring joint, lower part (4)
    • Oil ring spacer joint (3)