Envoy, Rainer, Trailblazer 2006-2007

Rocker Arms & Shafts

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Removal & Installation



4.2L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:
    NOTE
    Make sure to place the camshaft caps in a rack to keep them in order, so they may be installed in their original locations.


    NOTE
    If valve train components, such as the rocker arms or lash adjusters, are to be reused, they must be tagged or arranged to insure installation in their original locations.



    Camshaft cover
     



    Camshaft cap bolts and caps
     
    Camshafts
     



    Rocker arms
     
    Valve lash adjusters
     

  4.  

To install:

  1. Lubricate and fill the valve lash adjusters and the rocker arm roller with engine oil.
  2.  
  3. Install or connect the following

    Valve lash adjusters, in their original locations
     
    Rocker arm rollers in their original positions
     
    Camshafts
     
    Camshaft cap bolts
     
    Camshaft cover
     

  4.  

5.3L & 6.0L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:
    NOTE
    If valve train components, such as the rocker arms, pushrods or pivot supports, are to be reused, they must be tagged or arranged to insure installation in their original locations.



    Rocker arm cover(s)
     



    Rocker arm bolts
     
    Rocker arms
     
    Rocker arm pivot support
     
    Pushrods
     

  4.  

To install:

  1. Inspect and replace components if worn or damaged.
  2.  
  3. Coat the bearing surfaces of the rocker arms, pushrods and the flange of the rocker arm bolts with clean engine oil.
  4.  
  5. Install or connect the following:
    NOTE
    Make sure the pushrods are seated properly to the ends of the rocker arms, but do not tighten the bolts yet.



    Rocker arm pivot support
     
    Pushrods making sure they seat properly in the lifter sockets
     



    Rocker arms and bolts
     

  6.  
  7. Rotate the crankshaft until the No. 1 piston is at Top Dead Center (TDC) of the compressor stroke. In this position, the cylinder No. 1 rocker arms will be off lobe lift, and the crankshaft sprocket key will be at the 1:30 position.
    NOTE
    The engine firing order is: 1-8-7-2-6-5-4-3. Cylinders 1, 3, 5 and 7 are the left bank. Cylinders 2, 4, 6 and 8 are the right bank.

  8.  
  9. With the engine in the No. 1 firing position, tighten the following rocker arm bolts:
    1. Tighten cylinders 1, 2, 7 and 8 exhaust valve rocker arm bolts to 22 ft. lbs. (30 Nm).
    2.  
    3. Tighten cylinder 1, 3, 4 and 5 intake valve rocker arm bolts to 22 ft. lbs. (30 Nm).

      Click image to see an enlarged view

      Fig. View of the crankshaft key with the No. 1 piston at TDC-5.3L engine

    4.  

  10.  
  11. Rotate the crankshaft 360 degrees, then tighten the following rocker arm bolts:
    1. Tighten cylinders 3, 4, 5 and 6 exhaust valve rocker arm bolts to 22 ft. lbs. (30 Nm).
    2.  
    3. Tighten cylinder 2, 6, 7 and 8 intake valve rocker arm bolts to 22 ft. lbs. (30 Nm).
    4.  

  12.  
  13. Install the rocker arm cover(s).
  14.  

 
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