Removal Procedure
- Remove the valve rocker arm cover. Refer to the appropriate procedure:
- Remove the valve rocker arms.
- Remove the valve rocker arm supports.
- Remove the valve pushrods.
- Mark, sort, and organize the components for assembly.
- Clean the components with cleaning solvent.
- Dry the components with compressed air.
- Inspect the valve rocker arm components for the following:
- Inspect the valve pushrods for the following:
- Inspect the valve rocker support for excessive wear or damage.
Important: Mark, sort, and organize all the components for assembly.
Important: Parts that are to be reused must be marked, sorted, and organized for assembly.
| • | Valve rocker arm valve pushrod socket contact surface (1) |
| • | The contact surface must be smooth with no scoring or excessive wear. |
| • | Valve rocker arm roller pivot for binding or damage (2) |
| • | Valve rocker arm valve stem contact surface (3) |
| • | The contact surface should be smooth with no scoring or excessive wear. |
| • | Valve rocker arm bolt threads for damage (4) |
| • | Restriction of the oil passage (1) |
| • | Wear or scoring of the end contact surfaces (2) |
| • | The end contact surfaces must be smooth with no scoring or excessive wear. |
| • | Shaft for bends (3) |
| • | Roll the valve pushrod on a flat surface to determine if the valve pushrod is bent. |
Installation Procedure
- Install the valve pushrods.
- Install the valve rocker arm supports.
- Apply prelube GM P/N 12345501 or equivalent to the following valve rocker arm contact surfaces:
- Install the valve rocker arm assemblies as follows:
- Rotate the crankshaft balancer to position the crankshaft balancer alignment mark (1) 57-63 degrees clockwise or counterclockwise from the engine front cover alignment tab (2).
- Tighten the valve rocker arm bolts.
- Install the valve rocker arm cover. Refer to the appropriate procedure:
Important: Be sure to keep parts in order. Parts must be reinstalled into the original location and position.
Important: Be sure that the arrow on the valve rocker arm support is in the up position.
| • | Valve pushrod socket (1) |
| • | Roller pivot (2) |
| • | Valve stem tip (3) |
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
| 4.1. | Finger start the bolt at location (1). |
| 4.2. | Finger start the bolt at location (2). |
| 4.3. | Finger start the bolt at location (3). |
| 4.4. | Finger start the remaining valve rocker arm bolts. |
Important: Once the valve rocker arm assemblies are installed and properly torqued, no additional valve lash adjustment is required.
Tighten
Tighten valve rocker arm bolts to 30 N·m (22 lb ft).
