Cylinder Head Cleaning and Inspection

Tools Required 

• J 8001  Dial Indicator Set
• J 8089  Carbon Removing Brush
• J 9666  Valve Spring Tester

1. Clean the valve stems and cylinder heads on a buffing wheel.
2. Clean the following components in cleaning solvent:
   • Valve stem keys (1)
   • Valve spring cap (2)
   • Valve spring (3)
   • Cylinder head
3. Dry the components with compressed air.
   Fig 1: Valve Spring Components

   Courtesy of GENERAL MOTORS CORP.
4. Use the J 8089  to clean the carbon from the cylinder head combustion chambers.

   Be careful not to scuff the combustion chambers.

5. Inspect the cylinder head for the following:
   • Damage to the gasket surfaces
   • Damage to the threaded bolt holes
   • Burnt or eroded areas in the combustion chamber
   • Cracks in the exhaust ports and combustion chambers
   • External cracks in the water chamber
   • Restrictions in the intake or exhaust passages
   • Restrictions in the cooling system passages
   • Rusted, damaged, or leaking core plugs
   Fig 2: Cleaning Carbon From Cylinder Head Using J 8089

   Courtesy of GENERAL MOTORS CORP.
6. Measure the cylinder head for warpage with a straight edge and feeler gage.
   • A cylinder head block deck with warpage in excess of 0.10 mm (0.004 in) within a 152.4 mm (6.0 in) area must be repaired or replaced.
   • A cylinder head exhaust manifold deck with warpage in excess of 0.05 mm (0.002 in) within a 152.4 mm (6.0 in) area must be repaired or replaced.
   • A cylinder head intake manifold deck with warpage in excess of 0.10 mm (0.004 in) within a 152.4 mm (6.0 in) area must be repaired or replaced.
   Fig 3: Measuring Cylinder Head

   Courtesy of GENERAL MOTORS CORP.
7. Use the J 9666  in order to measure the valve spring.

   Replace the valve spring if the valve spring tension is less than 338 N (76 lb) at 43.2 mm (1.70 in).

   Fig 4: Measuring Valve Spring Using J 9666

   Courtesy of GENERAL MOTORS CORP.
8. Inspect the valve springs for squareness.
   Fig 5: Valve Springs

   Courtesy of GENERAL MOTORS CORP.
9. Valve stems (1) with excessive valve guide (2) clearance must be repaired or the cylinder head replaced.
   Fig 6: Valve Stems

   Courtesy of GENERAL MOTORS CORP.
10. Measure the valve stem-to-guide clearance.

    Excessive valve stem-to-guide clearance may cause an excessive oil consumption and may also cause a valve to break. Insufficient clearance will result in noisy and sticky functioning of the valve and will disturb the engine assembly smoothness.

    1. 10.1. Clamp the J 8001  on the exhaust port side of the cylinder head.
    2. 10.2. Position the dial indicator so that the movement of the valve stem from side to side, crosswise to the cylinder head, will cause a direct movement of the dial indicator stem.

       The dial indicator stem must contract the side of the valve stem just above the valve guide.

    3. 10.3. Drop the valve head about 1.6 mm (0.063 in) off the valve seat.
    4. 10.4. Use light pressure and move the valve stem from side to side in order to obtain a valve stem-to-guide clearance reading.

       Refer to Engine Mechanical Specifications .

    Fig 7: Measuring Valve Stem-To-Guide Clearance

    Courtesy of GENERAL MOTORS CORP.