Cylinder Head Cleaning and Inspection

Tools Required 

• J 8001  Dial Indicator
• J 8089  Wire Brush
• J 9666  Valve Spring Tester

1. Use the J 8089  in order to clean the carbon from the combustion chambers and the valve parts. Be careful not to scuff the combustion chambers and valve stems.
2. Clean the following areas:
   • The carbon and the sludge from the valve pushrods and the valve rocker arms
   • The valve stems and heads on a buffing wheel
   • The cylinder head and engine block gasket surfaces
   • The bolt hole threads in the cylinder heads and the engine block
3. Inspect the following areas:
   • The cylinder head for cracks in the exhaust ports and combustion chambers
   • The cylinder head for external cracks in the water chamber
   • The valves for burned heads, cracked faces, or damaged stems
   • The valve springs for squareness
4. Inspect the cylinder head deck face flatness with a straight edge. Refer to Engine Mechanical Specifications .
5. Use the J 9666  in order to measure the valve spring.

   Replace the spring if the spring tension is less than 325 N (73.1 lb) at 40.64 mm (1.600 in).

Fig 1: Measuring Valve Spring Using J 9666
Courtesy of GENERAL MOTORS CORP.
6. Measure the valve stem-to-guide clearance.
   • Excessive valve stem-to-guide clearance may cause excessive oil consumption and may cause a valve to break. Insufficient clearance will result in noisy and sticky functioning of the valve, will disturb the engine assembly smoothness, and could result in a scuffed valve stem.
   • Clamp the J 8001  on the exhaust port side of the cylinder head.
   • Locate the 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 indicator stem.

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

   • Drop the valve head about 1.6 mm (0.063 in) off the valve seat.
     Fig 2: Measuring Valve Stem-To-Guide Clearance

     Courtesy of GENERAL MOTORS CORP.
   • Use light pressure when moving the valve stem from side to side in order to obtain a clearance reading.
   • Ream the intake valve guides for oversize valves if the clearance exceeds 0.053 mm (0.0020 in) on the intake valve.
   • Ream the exhaust valve guides for oversize valves if the clearance exceeds 0.075 mm (0.0029 in).