Cylinder Head Assembly: Service and Repair
REMOVAL1. Disconnect the battery negative cable.
2. Drain cooling system.
3. Remove the engine cover.
4. Remove the heat shields (Fig. 9) (Fig. 10).
5. Remove the generator.
6. Remove closed crankcase ventilation system.
7. Disconnect the evaporation control system.
8. Remove the air cleaner.
9. Perform fuel system pressure release procedure.
10. Disconnect the fuel supply line.
11. Disconnect accelerator linkage and if so equipped, the speed control and transmission kickdown cables.
12. Remove distributor cap and wires.
13. Disconnect the coil wire.
14. Disconnect coolant temperature sending unit connector.
15. Disconnect heater hoses and bypass hose.
16. Disconnect all remaining electrical and vacuum harness connections.
17. Remove cylinder head covers and gaskets.
18. Remove intake manifold and throttle body as an assembly Discard the flange side gaskets and the front and rear cross-over gaskets.
19. Remove exhaust manifolds.
20. Remove rocker arm assemblies and push rods. Identify to ensure installation in original locations.
21. Remove the head bolts from each cylinder head and remove cylinder heads. Discard the cylinder head gasket.
22. Remove spark plugs.
CLEANING
Clean all surfaces of cylinder block and cylinder heads. Clean cylinder block front and rear gasket surfaces using a suitable solvent.
INSPECTION
1. Inspect all surfaces with a straightedge if there is any reason to suspect leakage. If out-of-flatness exceeds 0.00075mm/mm (0.0001in/inch) times the span length in any direction, either replace head or lightly machine the head surface.
EXAMPLE: A 305 mm (12 in.) span is 0.102 mm (0.004 in.) out-of-flat. The allowable out-of flat is 305 x 0.00075 mm (12 x 0.00075 in.) equals 0.23 mm (0.009 in.). This amount of out-of-flat is acceptable. The cylinder head surface finish should be 1.78 - 3.00 microns (70 - 125 micro-inches).
2. Inspect push rods. Replace worn or bent rods.
INSTALLATION
1. Clean all surfaces of cylinder block and cylinder heads.
2. Clean cylinder block front and rear gasket surfaces using a suitable solvent.
3. Position the new cylinder head gaskets onto the cylinder block.
4. Position the cylinder heads onto head gaskets and cylinder block.
5. Starting at top center, tighten all cylinder head bolts, in sequence, to 68 Nm (50 ft. lbs.) torque (Fig. 11). Repeat procedure, tighten all cylinder head bolts to 143 Nm (105 ft. lbs.) torque. Repeat procedure to confirm that all bolts are at 143 Nm (105 ft. lbs.) torque.
CAUTION:
^ When tightening the rocker arm bolts, make sure the piston in that cylinder is NOT at TDC. Contact between the valves and piston could occur.
^ DO NOT rotate or crank the engine during or immediately after rocker arm installation. Allow the hydraulic roller tappets adequate time to bleed down (about 5 minutes).
6. Install push rods and rocker arm assemblies in their original position.
7. Install exhaust manifolds.
8. Install the intake manifold and throttle body assembly.
9. Adjust spark plugs to specifications. Install the plugs.
10. Install coil wire.
11. Connect the coolant temperature sending unit connector.
12. Connect the heater hoses and bypass hose.
13. Install distributor cap and wires.
14. Connect the accelerator linkage and if so equipped, the speed control and transmission kickdown cables.
15. Connect all of the previously disconnected electrical and vacuum harnesses.
16. Install the fuel supply line.
17. Install the generator and drive belt.
18. Place new cylinder head cover gaskets in position and install cylinder head covers.
19. Install closed crankcase ventilation system.
20. Connect the evaporation control system.
21. Install the air cleaner.
22. Install the heat shields. Tighten the bolts to 6 Nm (55 in. lbs.) torque.
23. Fill cooling system.
24. Connect the battery negative cable.
25. Change the engine oil and filter.
26. Start the engine and check for leaks.
27. Install the engine cover.