Cylinder Head Assembly: Service and Repair
REMOVAL
The alloy cast iron cylinder heads (Fig. 8) are held in place by eight bolts. The spark plugs are located at the peak of the wedge between the valves.
1. Disconnect the battery negative cable from the battery.
2. Drain cooling system.
3. Remove the intake manifold-to-generator bracket support rod. Remove the generator.
4. Remove closed crankcase ventilation system.
5. Disconnect the evaporation control system.
6. Remove the air cleaner, air in-let hose and resonator.
7. Perform fuel system pressure release procedure.
8. Disconnect the fuel supply line from the fuel rail.
9. Disconnect accelerator linkage and if so equipped, the speed control and transmission kickdown cables.
10. Remove distributor cap and wires.
11. Disconnect the coil wires.
12. Disconnect coolant temperature sending unit wire.
13. Disconnect heater hoses and bypass hose.
14. Disconnect the vacuum supply hoses from the intake manifold.
15. Disconnect the fuel injector harness and secure out of the way.
16. Remove cylinder head covers and gaskets.
17. Remove intake manifold and throttle body as an assembly. Discard the flange side gaskets and the front and rear cross-over gaskets.
18. Remove exhaust manifolds.
19. Remove rocker arm assemblies and push rods. Identify to ensure installation in original locations.
20. Remove the head bolts from each cylinder head and remove cylinder heads. Discard the cylinder head gasket.
21. 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
Inspect all surfaces with a straightedge if there is any reason to suspect leakage. If out-of-flatness exceeds 0.00075 mm/mm (0.000l in/in.) times the span length in any direction, either replace head or lightly machine the head surface.
FOR EXAMPLE: -A 305 mm (12 inch) span is 0.102 mm (0.004 inch) out-of-flat. The allowable out-of-flat is 305 x 0.00075 (12 x 0.00075) equals 0.23 mm (0.009 inch). This amount of out-of-flat is acceptable.
The cylinder head surface finish should be 1.78-3.00 microns (70-125 microinches).
Inspect push rods. Replace worn or bent rods.
INSTALLATION
The alloy cast iron cylinder heads (Fig. 8) are held in place by eight bolts. The spark plugs are located at the peak of the wedge between the valves.
1. Position the new cylinder head gaskets onto the cylinder block.
2. Position the cylinder heads onto head gaskets and cylinder block.
3. Starting at top center, tighten all cylinder head bolts, in sequence, to 68 Nm (50 ft. lbs.) torque (Fig. 8). 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, be sure the piston in that cylinder is NOT at TDC. Contact between the valves and piston could occur.
4. Install push rods and rocker arm assemblies in their original positions. Tighten the bolts to 28 Nm (21 ft. lbs.) torque.
5. Install the intake manifold and throttle body assembly.
6. Install exhaust manifolds.
7. Adjust spark plugs to specifications. Install the plugs and tighten to 41 Nm (30 ft. lbs.) torque.
8. Install coil wires.
9. Connect coolant temperature sending unit wire.
10. Connect the fuel injector harness.
11. Connect the vacuum supply hoses to the intake manifold.
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. Install the fuel supply line.
16. Install the generator and accessory drive belt. Tighten generator mounting bolt to 41 Nm (30 ft. lbs.) torque.
17. Install the intake manifold-to-generator bracket support rod. Tighten the bolts.
18. Install cylinder head covers.
19. Install closed crankcase ventilation system.
20. Connect the evaporation control system.
21. Install the resonator assembly, air in-let hose and air cleaner.
22. Install the heat shields. Tighten the bolts to 41 Nm (30 ft. lbs.) torque.
23. Fill cooling system.
24. Connect the battery negative cable.