Balancer and Oil Pump Installation

Special Tools

• EN-51162  Balancer Backlash Tool
• EN-51265  Crankshaft Locking Tool
• GE-7872  Dial Indicator

For equivalent regional tools, refer to Special Tools .

1. Courtesy of GENERAL MOTORS COMPANY

   Ensure that the timing mark on the crankshaft timing pulley (1) is aligned at 90 degrees ATDC with the mark on the front cover (1).

2. Courtesy of GENERAL MOTORS COMPANY

   Install EN-51265  locking tool.

3. Courtesy of GENERAL MOTORS COMPANY

   Install the balancer assembly (4).

   Install the balancer assembly tube bolts (1) and hand tighten.

4. Courtesy of GENERAL MOTORS COMPANY

   Install the fasteners in sequence, hand tighten.

5. Courtesy of GENERAL MOTORS COMPANY

   Remove EN-51265  locking tool.

6. Courtesy of GENERAL MOTORS COMPANY

   Remove GM P/N 12628143 balancer shaft gear pin (1).

7. Courtesy of GENERAL MOTORS COMPANY

   NOTE:

   A NEW balancer contains a coating on a portion of the drive gear which can lead to errors in backlash reading. The crankshaft must be rotated so that the coating is not in contact with the crankshaft gear.

   Rotate crankshaft 90 degrees until the flat on the balancer shaft (1) is facing the bottom of the engine.

8. Courtesy of GENERAL MOTORS COMPANY

   Push the balancer in the direction shown as far as it will go.

9. Courtesy of GENERAL MOTORS COMPANY

   Position a magnetic dial gauge on the block and set the gauge to zero on the pad of the balancer.

10. Courtesy of GENERAL MOTORS COMPANY

    NOTE:

    The balancer may not move, this is normal.

    Push the balancer in the direction shown until the dial gauge reads at least 0. 4 mm movement. The balancer is climbing over the crankshaft gear.

11. Courtesy of GENERAL MOTORS COMPANY

    Using a soft mallet, gently tap the balancer in the direction shown until the dial gauge reads 0.

12. Hand tighten the balancer bolts.

13. Courtesy of GENERAL MOTORS COMPANY

    Install EN-51162 - 2  Pre-load Screw Assembly to the block in the position shown and tighten to the block.

14. Hand tighten the screw until it contacts the body of the balancer.

15. Courtesy of GENERAL MOTORS COMPANY

    Install the EN-51162 - 1  balancer backlash tool as shown.

16. While pushing the balancer shaft toward the front of the engine with your thumb, use finger pressure to push up and down on the EN-51162 - 1  balancer backlash tool and read the total deflection on the dial indicator. The backlash specification (a) is 0. 06 - 0. 15 mm (0. 002 - 0. 006 in).

17. Courtesy of GENERAL MOTORS COMPANY

    Record the readings on the dial indicator.

    1. If the balancer backlash is correct or very close, tighten the balancer bolts in sequence to 32 N. m (24 lb ft) and check the backlash again. If the backlash is still correct after tightening, go to step 20.
    2. If the balancer backlash is too high, go to step 18.
    3. If the balancer backlash is too low, go to step 19.
18. Backlash too high.
    1. Slightly loosen the balancer bolts.
    2. Turn the Pre-load screw clockwise a very small amount.
    3. Hand tighten the balancer bolts.
    4. Repeat steps 13 and 14 to measure balancer backlash.
19. Backlash too low.
    1. Slightly loosen the balancer bolts.
    2. Loosen the Pre-load screw counter-clockwise a very small amount.
    3. Gently tap the balancer on the right side with a rubber mallet to bring it in contact with the Pre-load screw.
    4. Hand tighten the balancer bolts.
    5. Repeat steps 13 and 14 to measure balancer backlash.

20. Courtesy of GENERAL MOTORS COMPANY

    Tighten the balance shaft tube bolts (1) to 25 N. m (18 lb ft).

21. Remove the tools.