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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1021 (Engine Mechanical - 8.1L) >> Repair Instructions >> Off-Vehicle Repair Instructions >> Crankshaft and Bearings Cleaning and Inspection >> Crankshaft Inspection

Crankshaft Inspection

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    IMPORTANT: Use care when handling the crankshaft. Avoid damage to the bearing surfaces.
  1. Clean the crankshaft in solvent. Remove all sludge or restrictions from the oil passages.
    2. Fig 1: View Of Crankshaft Removed
    GM639519Courtesy of GENERAL MOTORS CORP.
    CAUTION: Refer to Safety Glasses Caution in Cautions and Notices.
  2. Dry the crankshaft and bearings with compressed air.
  3. Inspect the crankshaft for the following conditions:
    • Crankshaft journals (1) should be smooth with no evidence of scoring or damage
    • Deep grooves (2)
    • Scratches or uneven wear (3)
    • Pitted surfaces (4)
    • Wear or damage to the thrust journal surfaces
    • Scoring or damage to the rear seal surface
    • Restrictions to oil passages
    • Damage to threaded bolt holes
    4. Fig 2: View Of Crankshaft Inspection Areas
    GM677825Courtesy of GENERAL MOTORS CORP.
    IMPORTANT: The crankshaft pin is a pressed-in- place roll pin. The pin only needs to be removed from the crankshaft if the pin is damaged.
  4. Inspect the crankshaft pin for damage:
    • Measure for proper installed height (a). Correct height should be 2.00-2.25 mm (0.078-0.088 in).
    • Replace the crankshaft pin if it is damaged.
    5. Fig 3: View Of Crankshaft Pin Measurement
    GM639543Courtesy of GENERAL MOTORS CORP.
    IMPORTANT: Do NOT attempt to remove the crankshaft reluctor wheels. If the reluctor wheels are damaged and/or removed, the crankshaft must be replaced.
  5. Inspect the reluctor wheels for cracked, bent or broken teeth.
    • Measure between the crankshaft shoulder and the front reluctor wheel (1).
    • Measure between the gap between the front and rear reluctor wheels (2). The maximum allowable gap is 0.15 mm (0.006 in).
    6. Fig 4: View Of Reluctor Wheels Inspection Areas
    GM677772Courtesy of GENERAL MOTORS CORP.
  6. Measure the crankshaft main journals and the crankpins for out-of-round and taper.
    7. Fig 5: Measuring Crankshaft Journals
    GM35207Courtesy of GENERAL MOTORS CORP.
  7. Using a suitable fixture, support the crankshaft.
    1. Measure the crankshaft runout using J 7872  .
    2. Crankshaft runout should not exceed 0.051 mm (0.002 in).
    8. Fig 6: Measuring Crankshaft Runout Using J 7872
    GM677818Courtesy of GENERAL MOTORS CORP.
  8. Inspect the crankshaft thrust wall surface (1) for wear and/or excessive runout (2). Refer to Engine Mechanical Specifications .
    9. Fig 7: View Of Crankshaft Thrust Wall Surface Inspection Area
    GM639520Courtesy of GENERAL MOTORS CORP.
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