Valve Lifters This engine uses hydraulic valve lifters. Valve lifters are serviced only as an assembly. No internal parts are available. Service is limited to disassembly and cleaning. Discard valve lifters that are excessively worn or damaged. IMPORTANT: Whenever the camshaft needs to be replaced, a new set of hydraulic lifters must also be installed. Cylinder Head Disassembly Figures 12-48 and 12-49 Tool Required: J 8062 Valve Spring Compressor Remove or Disconnect 1 . Compress the springs with J 8062 (figure 12-48). 2 . Keys. 3 . Valve spring cap. 4 . Spring. 5 . Seal. 6 . Valves. IMPORTANT:
Place the valves in an organizer rack so they can be replaced in their original position at reassembly. Figure 12-49 Valves and Components Cleaning, Inspection, and Measurement Figures 12-50 through 12-54 Tool Required: J 8089 Wire brush Clean • Carbon from the combustion chambers using J 8089. • Valve stems and heads on a wire wheel. • Carbon and old gasket from the cylinder head gasket surface. • Valve guides using a valve guide cleaner. Inspect • Cylinder head for cracks in the exhaust ports, combustion chambers, or external cracks to the coolant chamber. Gasket surfaces should be free of damage. • Valves for burning, pitting, or warpage. Refer to “Valve Grinding” in this Section.
Check the valve stems for scoring or excessive wear. Stems must not be bent. • Valve rocker arm studs for wear, damage, or improper fit. • Valve seats for pitting or other damage. Grind or reface as needed. • Rotators (if used). The rotators should move smoothly without binding. • Cylinder head for surface flatness (figure 12-51). Figure 12-48 Compressing Valve Springs G643 (E) Service Manual Chapter 3. Engine Mechanical System 86