Removal Procedure
- Remove the lower valve
rocker arm covers. Refer to
Valve Rocker Arm Cover Replacement - Lower Left Side
or
Valve Rocker Arm Cover Replacement - Lower Right Side
.
- Loosen the valve clearance lock nuts on each rocker arm.
- Loosen the valve clearance adjusting screw on each rocker arm
to relieve tension on the valve train.
Important: The valve rocker arm bolts retain the rocker arms on the shaft. Do not
remove the bolts from the rocker arm shaft brackets.
- Loosen the rocker arm
shaft assembly bolts in the proper sequence. Leave the bolts in the rocker
arm shaft brackets.
- Remove the rocker arm shaft assembly from the cylinder head.
- Remove the valve bridge
pins.
- Remove the valve bridges.
- Remove the valve push rods.
- Clean all parts in a suitable cleaning solvent.
Disassembly Procedure
- Remove the rocker arm
shaft bracket bolts (1).
- Remove the bracket (12), rocker arm exhaust (11)
and spring (10).
- Remove the remaining rocker arms, springs, and brackets.
Inspection and Repair
- Using a micrometer, measure the rocker arm shaft outside diameter at
the locations of the rocker arm.
The production value is 21.979-22 mm (0.8653-0.8661 in)
and the service limit is 21.85 mm (0.8602 in).
Replace the rocker arm shaft if the measurement value is less than the
service limit.
- Measure the rocker arm inside diameter.
The production value is 22.01-22.035 mm (0.8665-0.8675 in).
- Replace the rocker arm if the measurement exceeds the service
limit.
- Inspect the valve clearance adjusting screw for damage.
Replace the valve clearance adjusting screw if damage is found.
- Inspect the valve bridge and the valve bridge pin for damage.
- Replace the valve bridge or valve bridge pin if damage is found.
- Measure the pushrod for
warpage.
- Replace the pushrod if the warpage exceeds 0.8 mm (0.031
in).
Assembly Procedure
- Lubricate the rocker arm
shaft (7) and the inside of the rocker arms with clean engine oil.
- Install the rocker arm bracket (12) on one end of the rocker
arm shaft with bolt.
- Install the rocker arm intake (9), spring (10),
rocker arm exhaust (11), and the bracket with bolt. Continue in the
same sequence to the last bracket.
- Push the bracket to compress the springs and then install the
bolt.
Installation Procedure
- Lubricate the top of the
valves, the valve bridge stem, the valve bridge, and the valve bridge pins
with clean engine oil.
- Install the valve bridge pins.
- Install the valve bridges.
- Lubricate the valve lifter end of the pushrod with clean engine
oil.
- Install the pushrods.
To ensure the pushrod is properly installed, gently pull up on the pushrod.
You should feel resistance from the pushrod trying to lift the valve lifter.
- Lubricate the following with clean engine oil during installation:
• | Rocker arm shaft bolt threads |
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.
- Install the rocker
arm shaft assembly to the cylinder head.
Tighten
Tighten the rocker arm shaft bolts to 41 N·m (30 lb ft)
in the proper sequence.
- Adjust the valve clearance. Refer to
Valve Clearance Adjustment
.
- Install the lower valve rocker arm cover. Refer to
Valve Rocker Arm Cover Replacement - Lower Left Side
or
Valve Rocker Arm Cover Replacement - Lower Right Side
.