Camshaft and Bearings Cleaning and Inspection: Notes

Tools Required 

• J 7872  Magnetic Base Dial Indicator Set
• J 8520  Camshaft Lobe Lift Indicator

1. Clean the components in solvent.
   CAUTION: Refer to SAFETY GLASSES CAUTION .
2. Dry the components with compressed air.
3. Inspect the camshaft bearing journals (1) for scoring or excessive wear.
4. Inspect the camshaft valve lifter lobes (2) for scoring or excessive wear.
5. Inspect the threaded bolt holes (3) in the front of the camshaft for damaged threads or debris.
6. Inspect the camshaft sprocket pin (4) for damage.
7. Inspect the camshaft position reluctor ring for nicks or damage.
   Fig 1: Identifying Camshaft Components

   Courtesy of GENERAL MOTORS CORP.
8. Inspect the camshaft retainer plate for wear or a damaged sealing gasket.

   If the camshaft retainer plate sealing gasket is not cut or damaged, it may be used again.

   Fig 2: Inspecting Camshaft Retainer Plate For Wear

   Courtesy of GENERAL MOTORS CORP.
9. Inspect the camshaft bearings for proper fit in the engine block. The camshaft bearings have an interference fit to the engine block and should not be loose in their engine block bearing bores.
10. Inspect the camshaft bearings for excessive wear or scoring.

    Bearings with excessive scoring or wear must be replaced.

    Fig 3: Inspecting Camshaft Bearings For Proper Fit In Engine Block

    Courtesy of GENERAL MOTORS CORP.
11. Measure the camshaft journals for wear and out-of-round with a micrometer.
    • A camshaft with bearing journals that measure more than 0.025 mm (0.001 in) out-of-round, must be replaced.
    • A camshaft with bearing journal diameters that measure less that 54.99 mm (2.164 in), must be replaced.
    Fig 4: Measuring Camshaft Journals

    Courtesy of GENERAL MOTORS CORP.
12. Measure the camshaft lobes for wear with a micrometer.
    • An LS1 camshaft with an intake lobe that measures 46.31 mm (1.823 in) or less, must be replaced.
    • An LS1 camshaft with an exhaust lobe that measures 46.31 mm (1.823 in) or less, must be replaced.
    • An LS6 camshaft with an intake lobe that measures 46.24 mm (1.82 in) or less, must be replaced.
    • An LS6 camshaft with an exhaust lobe that measures 46.19 mm (1.818 in) or less, must be replaced.
    Fig 5: Measuring Camshaft Lobes

    Courtesy of GENERAL MOTORS CORP.
13. Measure the camshaft runout.
    1. 13.1. Mount the camshaft in wooden V-blocks or between centers on a fixture.
    2. 13.2. Check the runout of the intermediate camshaft bearing journals using the J 7872  .
    3. 13.3. If camshaft runout exceeds 0.05 mm (0.002 in), the camshaft is bent and should be replaced.
    Fig 6: Measuring Camshaft Runout

    Courtesy of GENERAL MOTORS CORP.