Cylinder Head Assembly: Service and Repair

Fig. 1 Cylinder head torque sequence.:

1. Drain cooling system, disconnect battery, and disconnect exhaust pipe from manifold.
2. Remove battery, air filter, radiator overflow bottle, vacuum pump, and fuel injection pipes.
3. Disconnect water hoses at water pump.
4. Disconnect electrical connections.
5. Disconnect heater hose and rocker shaft oil feed line at cylinder head.
6. Remove valve cover, rocker shaft assembly and pushrods.
7. Loosen cylinder head bolts according to sequence in Fig. 1.
8. Remove cylinder head.
9. Select head gasket according to piston projection above deck. If projection is no greater than .033 inch (.84 mm) on XD2 and XD2C engines, or .031 inch (.079 mm) on XD2S engines use a gasket with a thickness of .062 inch (1.58 mm). If projection is greater than .033 inch (.84 mm), on XD2 and XD2C engines or .031 inch (.079 mm) on XD2S engines use a gasket with thickness of .067 inch (1.70 mm).
10. Install gasket dry with oblong flame ring side facing cylinder head plane.
11. Install cylinder head. Torque in sequence, Fig. 1. On XD2 and XD2C engines, pretorque to 21.75 ft. lbs. (3 m-kg), then torque to 47.13 ft. lbs. (6.5 m-kg). Then loosen each bolt 1/4 turn and retorque to 47.13 ft. lbs. On XD2S engines, pretorque to 21.75 ft. lbs., then to 50.75 ft. lbs. (7 m-kg). Loosen each bolt 1/4 turn and retorque to 50.75 ft. lbs.
12. Install pushrods, rocker shaft assembly and oil feed union with its seal.

Fig. 2 Rocker arm play:

13. Tighten rocker shaft bearing blocks progressively, allowing .004 inch (.10 mm) play at the two end rocker arms, Fig. 2. Torque intermediate support nuts to 34 ft. lbs. (4.7 m-kg). Torque end support bolts to 14.5 ft. lbs. (2 m-kg).
14. Adjust valves and install valve cover.
15. Reinstall heater hose and rocker shaft oil feed pipe.
16. Reinstall hoses, pipes and manifolds.
17. Reinstall water pump belt, vacuum pump, fuel injection pipes, air filter, radiator overflow bottle and battery.