Cylinder Head Cleaning and Inspection

WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.

Tools Required

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

CAUTION: Refer to SAFETY GLASSES & COMPRESSED AIR CAUTION in Cautions and Notices.

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

Fig 1: Identifying Valve Stem Keys, Spring Cap, & Spring
Courtesy of GENERAL MOTORS CORP.
Use the J 8089 to clean the carbon from the cylinder head combustion chambers.
Be careful not to scuff the combustion chambers.
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: Using J 8089
  Courtesy of GENERAL MOTORS CORP.
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.
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: Using J 9666
Courtesy of GENERAL MOTORS CORP.
Inspect the valve springs for squareness.

Fig 5: Inspecting Valve Springs
Courtesy of GENERAL MOTORS CORP.
Valve stems (1) with excessive valve guide (2) clearance must be repaired or the cylinder head replaced,

Fig 6: Inspecting Valve Stems & Guide
Courtesy of GENERAL MOTORS CORP.
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: Using J 8001
  Courtesy of GENERAL MOTORS CORP.