Camshaft and Bearings Cleaning and Inspection

Tools Required
• Magnetic Base Dial Indicator Set
• Camshaft Lobe Lift Indicator

1. Clean the components in solvent.

   Caution

   Wear safety glasses in order to avoid eye damage.

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 (204) for damage.
7. Inspect the camshaft position reluctor ring for nicks or damage.
   
   
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.
   
   
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.
    
    
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.
    
    
    
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.
    
    
    
13. Measure the camshaft runout.
    1. Mount the camshaft in wooden V-blocks or between centers on a fixture.
    2. Check the runout of the intermediate camshaft bearing journals using the J 7872 .
    3. If camshaft runout exceeds 0.05 mm (0.002 in), the camshaft is bent and should be replaced.

Measuring Camshaft Lobe Lift

Important

Measuring camshaft lobe lift is a procedure used to determine if the camshaft lobes have worn. This test is to be performed prior to engine disassembly and with the camshaft and valve train components installed in the engine.

1. Measure camshaft lobe lift using J 8520 .
   1. Remove the valve rocker arms and bolts
   2. Install the dial indicator mounting stud into the valve rocker arm bolt hole.
   3. Assemble the components of the J 8520 and position onto the stud.
   4. Position the shaft of the dial indicator onto the end of the pushrod.
   5. Rotate the face of the dial indicator to zero.
   6. Slowly rotate the crankshaft clockwise until the dial indicator obtains its highest and lowest readings.
   7. Compare the total lift shown to specifications.
      • The proper lobe lift for the LS1 intake lobes is 6.96 mm (0.274 in).
      • The proper lobe lift for the LS1 exhaust lobes is 7.13 mm (0.281 in).
      • The proper lobe lift for the LS6 intake lobes is 8.24 mm (0.324 in).
      • The proper lobe lift for the LS6 exhaust lobes is 8.19 mm (0.322 in).
   8. Remove the tool.
2. Compare measurements to specifications. If the readings are not within specifications, remove the camshaft. Inspect and/or replace components as required.