GM Malibu/Cutlass 1997-2000

Balance Shafts

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NOTE
The balance shafts are only found on the 2.4L engine.

REMOVAL & INSTALLATION



2.4L Engine


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Fig. Remove the balance chain timing cover and loosen, but do not remove, the chain tensioner



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Fig. Remove the balance shaft driven sprocket. Remember that the sprocket bolt is left-hand thread



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Fig. Use the proper tool to prevent the balance shafts from turning while loosening the driven shaft sprocket bolt



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Fig. Remove the balance shaft housing fasteners



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Fig. These marks will line up when the balance shafts are in alignment



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Fig. The balance shaft housing-to-block fastener tightening sequence

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the oil pan assembly as outlined in this section.
  4.  
  5. Remove the balance shaft chain cover.
  6.  
  7. Loosen, but do not remove, the balance shaft chain tensioner.
  8.  
  9. Remove the oil pump cover and the oil pump assembly.
  10.  
  11. Rotate the engine until the number 1 piston is at TDC (Top Dead Center).
  12.  


WARNING
The balance shaft driven sprocket bolt is left-hand threaded and must be loosened by turning it in a CLOCKWISE direction. If it is not turned in a clockwise direction, it may break.

  1. Prevent the balance shafts from turning while loosening the driven shaft sprocket bolt.
  2.  
  3. Remove the sprocket bolt, and matchmark the sprocket to the driven balance shaft. Remove the driven sprocket from the balance shaft.
  4.  
  5. Remove the balance shaft housing fasteners and remove the balance shaft housing and shaft assembly.
  6.  
  7. Inspect the balance shafts, bearings and journals for wear and/or damage. Compare to the specifications in the charts at the end of this section.
  8.  
  9. Measure the gear backlash as specified later in this section. Correct or replace parts if necessary.
  10.  

To install:

  1. Install the balance shafts and housing assembly onto the engine block.
  2.  
  3. Apply sealant to the housing-to-block bolts.
  4.  
  5. Tighten the bolts in sequence to the proper torque values, as shown in the accompanying figure.
  6.  
  7. Install the balance shaft driven sprocket.
  8.  


WARNING
The balance shaft driven sprocket bolt is left-hand threaded and must be tightened by turning it in a COUNTER-CLOCKWISE direction.

  1. Tighten the sprocket bolt to 22 ft. lbs. (30 Nm).
  2.  
  3. Hold the balance shafts in the correct "timed" location and align the balance shaft drive chain with the teeth.
  4.  
  5. Install the oil pump as described in this section.
  6.  
  7. Install the balance shaft chain tensioner and tighten the bolt to 115 inch lbs. (13 Nm).
  8.  
  9. Install the balance shaft chain cover.
  10.  
  11. Install the oil pan using a new gasket.
  12.  
  13. Connect the negative battery cable.
  14.  

INSPECTION





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Fig. Remove the 8 upper-to-lower balance shaft housing bolts



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Fig. Inspect the bearings and the thrust plate for wear



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Fig. Measuring the balance shaft gear backlash



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Fig. Install the 8 upper-to-lower balance shaft housing bolts . . .



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Fig. . . . then tighten them in sequence to the proper torque values

  1. Remove the balance shaft assembly.
  2.  
  3. Remove the 8 upper-to-lower balance shaft housing bolts.
  4.  
  5. Separate the housings and remove the balance shafts.
  6.  
  7. Remove the bearings and the thrust plate from the housing.
  8.  
  9. Clean the housing, bearings, shafts, and the thrust plate.
  10.  
  11. Inspect the housing for:

    Cracks
     
    Scored bearing bores
     
    Damaged threaded holes
     

  12.  


NOTE
If the housings contain damage, replace the entire balance shaft assembly.

  1. Inspect the bearings for:

    Gouges
     
    Scoring
     
    Discoloration
     

  2.  
  3. Inspect the balance shafts for:

    Scores or burrs on journals
     
    Cracks or missing pieces
     

  4.  
  5. Inspect the thrust plate for:

    Gouges
     
    Burrs
     

  6.  
  7. Inspect the sprockets for:

    Bent teeth
     
    Broken teeth
     
    Chips
     
    Ground off teeth
     

  8.  
  9. Measure the balance shaft journals for following:

    Outside diameter
     
    Out of round
     

  10.  
  11. Measure the bearings for bearing clearance.
  12.  
  13. Measure the thrust plate thickness.
  14.  
  15. Measure the gears backlash using a dial indicator.
  16.  


WARNING
If one balance shaft needs replacing, they both must be replaced. Always replace the bearings when replacing the balance shafts.

  1. Compare all the measurements to the specifications in the charts at the end of this section. Replace any component(s) that are out of specification.
  2.  

To install:

  1. Install the bearings into housings and install the balance shafts.
  2.  
  3. Install the thrust plate and tighten the retaining bolts to 115 inch lbs. (13 Nm).
  4.  
  5. Verify the proper gear backlash using a dial indicator.
  6.  
  7. Install the upper and lower housings together and tighten the 8 upper-to-lower balance shaft housing bolts in sequence and to the proper torque values as shown in the accompanying figures and the chart at the end of this section.
  8.  
  9. Install the balance shaft housing onto the engine block.
  10.  

 
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