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For exploded view of the valve lever (rocker arm) and camshaft assembly, see Figure 31853 . ‪

1. Screw ‪

10. Roller Tappet Guide ‪

2. Timing Sensor Disk ‪

11. Camshaft Assembly ‪

3. Dowel Pin ‪

12. Retainer Ring ‪

4. Camshaft Gear ‪

13. Valve Adjusting Screw ‪

5. Bolt ‪

14. Valve Lever (Rocker Arm) ‪

6. Camshaft Thrust Plate ‪

15. Rocker Shaft Bracket ‪

7. Woodruff Key ‪

16. Rocker Arm Shaft Spring ‪

8. Pushrod ‪

17. Rocker Arm Shaft Plug ‪

9. Valve Roller Tappet ‪

18. Rocker Arm Shaft ‪

Rocker Arm Assembly, Camshaft, Tappets and Pushrods (Exploded View)


Remove the valve lever (rocker arm) as follows: ‪

  1. Loosen 12 valve lever adjusting screw nuts. See Figure 31110 .
    1. Loosen all valve lever adjusting screw nuts to loosen adjusting screw 1/2 turn.
    2. Loosen six (6) rocker arm bracket bolts (long cylinder head bolts).
    3. Lift rocker arm assembly from the cylinder head.
    4. NOTICE:

      Loosening the valve lever adjusting screw one half turn will avoid possible valve train damage during installation procedure. ‪

      1. Rocker Shaft Bracket ‪

      2. Cylinder Head ‪

      Removal of Valve Lever Assembly Rocker Arm)

  2. Remove six (6) long bolts and washers from rocker arm assembly and set aside.
  3. Remove six valve bracket bolts.

    Note: Measure the camshaft lobe lift.

Camshaft Lobe Lift

Camshaft wear can be measured without complete engine tear down. With the rocker arm assembly removed and the pushrods in place, measure the camshaft lobe lift as follows: ‪

  1. Mount a magnetic base dial indicator on the cylinder head
  2. Place dial indicator tip on top of pushrod and rotate engine until pushrod is at its lowest point of travel (base circle). Then "zero" indicator.
  3. Rotate the engine and bring the pushrod to its highest point of travel. Record the indicator reading.
  4. Repeat this procedure for all lobes.

    Note: Intake and exhaust valve lobe life specifications are different. If wear is greater than 8.51 mm (0.020 in.) replace the camshaft.

    Note: If a complete engine overhaul is scheduled, camshaft lobe wear can be determined by measuring lobes with a micrometer when the camshaft is removed.


Follow these steps to disassemble the rocker arm assembly. ‪

  1. Place rocker arm assembly on a clean flat surface.
  2. Using a snap ring tool, remove rocker arm retainer ring at end of shaft. See Figure 31914 .

    1. Retaining Ring ‪

    Rocker Arm Assembly

  3. Slide the rocker arm components off shaft. See Figure 31915 .

    1. Retaining Ring ‪

    4. Spring ‪

    2. Valve Lever ‪

    5. Shaft ‪

    3. Bracket ‪

    Rocker Arm Assembly

Cleaning of Rocker Arm Assembly

Follow these steps to clean the rocker arm assembly parts. ‪

  1. Immerse all components in a suitable solvent.

    To avoid injury from flying debris when using compressed air, wear adequate eye protection (face shield or safety goggles) and do not exceed 40 psi (276 kPa) air pressure.

  2. Remove and dry using filtered compressed air.
Inspection of Rocker Arm Assembly

Follow these steps to inspect the rocker arm assembly. ‪

  1. Visually inspect rocker arm shaft and bushings for scoring or signs of excessive wear. If visibly damaged, replace shaft and rocker arm, as required.

    Note: Valve levers have an oil spreader groove on the bushing. The oil spreader groove, 0.028 - 0.046 mm (0.011 - 0.018 in.) depth, is located opposite the oil hole and aids in oil dispersion over the entire bushing surface. See Figure 31912 .

    1. Part Number Location ‪

    2. Oil Spreader Groove ‪

    Oil Spreader Groove

    Note: Valve levers (rocker arms) have an oil spreader groove on the bushing. The oil spreader groove, 0.011-0.018 in. (0.028-0.046 mm) depth, is located opposite the oil hole and aids in oil dispersion over the entire bushing surface.

  2. Measure valve lever bushings using a telescoping gage and outside micrometer. See Figure 31913 . Measure bushings at two (2) locations, 90 degrees apart. Record the readings

    Measure Valve Lever Bushings

  3. Measure the valve lever shaft with a micrometer. If more than 0.13 mm (0.005 in.) difference is found between the valve lever bushing I.D. and the valve lever shaft O.D., replace the valve lever and/or shaft, whichever part is worn.
  4. If valve levers are within specifications, they may be reused. Prior to assembly, assure oil hole in valve levers and bushings is open by running a wire through the oil hole. Remove any blockage before assembly.
  5. Inspect all orifices for blockage. Run a wire through each to assure they are open. See Figure 31911 .

    Checking Rocker Arm Components

  6. Inspect valve lever (rocker arm) shaft springs as follows:
    1. Visually inspect for rust, pitting and cracks. Replace as required.
    2. Measure the spring tension using spring tester. See Figure 31910 .
    3. 1. Bracket ‪

      3. Spring ‪

      2. Valve Lever ‪

      Measure Spring Tension

    4. Measure free length (no load applied). Apply correct test load and measure test length.
    5. Replace rocker arm shaft springs that do not meet specifications.

Assembly of Rocker Arm Shaft

Follow these steps to assemble the rocker arm shaft components. ‪

  1. Lubricate all valve lever bushings with clean engine oil, install a retaining ring at one end of shaft and assemble components with rocker arm shaft in the vertical position. See Figure 31909 .

    Assemble Components

  2. Arrange rocker arm assembly components. See Figure 31903 .

    1. Retaining Ring ‪

    4. Spring ‪

    2. Valve Lever ‪

    5. Cup Plug ‪

    3. Bracket ‪

    6. Shaft ‪

    Rocker Arm Shaft

    Note: The rocker arm shaft is marked at the top. This marking should face up at all times.

    Note: Cup plugs at each end of the shaft are replaceable. They should not be removed unless damaged or leaking. If replacement is required, pry damaged plug out and press in a new cup plug. See Figure 31903 .

  3. Ensure the brackets are lined up over the shaft bolt grooves. See Figure 31904 .

    1. Cylinder Head ‪

    4. Mounting Bolt ‪

    2. Bracket ‪

    5. Shaft Hole Position ‪

    3. Rocker Arm Shaft ‪

    End View of Rocker Arm Shaft

  4. When all components of the valve lever (rocker arm) shaft have been installed in the correct order, attach a retaining ring to secure the component to the shaft. See Figure 31952 .

    Valve Lever Assembly


Follow these steps to install the valve lever assembly. ‪

  1. Install the valve lever assembly and adjust the valve lash. Refer to section .
  2. Install the valve cover/intake manifold and crankcase breather tube.