51. Cylinder Head Clean and Inspect
Cylinder Head Cleaning and InspectionTools Required
^ J8089 Carbon Removal Brush
^ J8001 Dial Indicator Set
^ J9666 Valve Spring Tester
^ J28410 Gasket Remover
Notice: Carefully clean the aluminum gasket surfaces in order to prevent damage to the sealing surfaces. Use only plastic, wood, or dull gasket scrapers, such as J28410. Follow the manufacturer's recommendations to dissolve gasket materials with chemical agents.
1. Remove all gasket material from the sealing surfaces using the J28410.
2. Use the J8089 to clean the carbon from the combustion chambers.
3. Using a valve guide bushing brush and solvent, clean all the valve guide bushings.
4. Using a soft brush and solvent, clean the cylinder head:
^ Intake and exhaust parts
^ Intake and exhaust valve seats
5. Inspect the cylinder head for flatness. Using a straight edge and a feeler gage, measure the surfaces contacting the cylinder block and manifolds for warpage. If the warpage is greater than the maximum, replace the cylinder head.
6. Inspect for the following in the cylinder head:
^ Cracks in the exhaust ports
^ Cracks in the combustion chambers
^ Cracks to the water jackets
^ Cracks in the valve seats
^ Valve seats for looseness
7. Use a buffing wheel to clean the valve stems and the valve heads.
8. Inspect the valves for the following:
^ Burnt or damaged areas (1)
^ Undersized valve margin (2)
^ Bent stems (3)
^ Scoring or other damage to the stem (4)
^ Worn key groove (5)
^ Worn stem tip (6)
9. Inspect the valve contact surface for the following conditions:
^ Undersized margin (1)
^ Pitted surface (2)
^ Burnt or eroded areas (3)
^ Acceptable edge, margin, (4)
Important: Minor imperfections of the valve may be corrected during reconditioning.
10. Valves with excessive damage must be replaced.
11. Perform the following steps to inspect the valve stem, 1 to valve guide, 2 clearance:
^ Clamp the J8001 on the exhaust port side of the cylinder head.
^ Locate the indicator so the movement of the valve stem crosswise to cylinder head will cause a direct movement of the indicator stem.
^ Drop the valve head 10 mm (0.39 inch) off the valve seat.
^ Using light pressure to move the stem of the valve side to side to obtain a clearance reading.
12. Measure the valve stem in 3 locations if the valve clearance is out of specifications.
^ Replace the valve if the valve stem is out of specification.
^ Ream the valve guide and use an oversized valve if the valve stem is within specification.
13. Inspect the valve springs for broken coils or coil ends.
14. Perform the following steps to inspect the valve for squareness:
^ Place the valve spring on a level surface next to a square.
^ Rotate the valve spring.
^ Replace the valve spring if the valve spring is more than 1.58 mm (0.062 inch) out of square.
15. Using calipers, measure the free length of the valve spring.
16. Use the J9666 in order to measure the valve spring force.