Removal and installation of the cylinder head of the Cummins ISF3.8 engine

We remove the cylinder head to replace the gasket under the cylinder head as well as for repair.

1. Disconnect the negative battery terminal.
2. Drain the coolant.
3. Remove the auxiliary drive belt (article — Replacing the auxiliary drive belt).
4. Remove the turbocharger.

5. Remove the exhaust manifold (for complete dismantling of the cylinder head; when replacing the gasket it may be left in place).
6. Remove the thermostat housing and withdraw the thermostat.
7. Remove the coolant bypass pipe.
8. Remove the high-pressure fuel pipes.
9. Unscrew and remove the fuel rail.
10. Remove the intake manifold.

11. To do this, loosen the clamps of the charge-air cooler air ducts and remove the air duct.

12. Unscrew the mounting bolts, remove the air elbow, the upper gasket, the intake air heater of the cold-start aid device and the lower gasket.

13. Remove the intake manifold pressure sensor with the temperature sensor as an assembly:
    • disconnect the intake manifold pressure sensor connector;
    • unscrew the screw;
    • remove the sensor strictly upwards, taking care not to damage the O-ring.
14. Unscrew all the intake manifold mounting bolts to the cylinder head and remove the intake manifold.

15. Extract the gasket.
16. Mask the passages in the cylinder head with tape to prevent dirt ingress.
17. Remove the fuel return pipes.
18. Disconnect the air compressor cooling pipes.
19. Remove the cylinder head cover:
    • disconnect the engine wiring;
    • loosen the cylinder head cover mounting screws (the screws are not removed and are part of the cover).

20. Carefully lift and remove the cover.

21. Remove the rocker arms, for this:
    • loosen the locknut;
    • unscrew the adjusting nut;
    • unscrew the rocker arm mounting bolts;
    • remove the rocker arms and valve bridges. The bridges and rocker arms must be installed in their places, so we mark them and lay them out on the table in the required order.

22. Remove the pushrods.

23. Mark the pushrods according to their location. The pushrods must be installed in their places.
24. Remove the injectors.

25. After this, evenly, in several passes, unscrew the bolts and remove the cylinder head.

Note: dismantling, inspection, cleaning and repair of the cylinder head will be covered in a separate article.

Installation of the cylinder head

1. Install a new cylinder head gasket.

Depending on the piston protrusion after grinding the cylinder head or block, a cylinder head gasket of one of three sizes may be installed. If the piston protrusion is exceeded by 0.5 mm, the cylinder block must be replaced.

Cylinder head gasket thickness:

• nominal gasket: 1.25 mm;
• repair No. 1: 1.50 mm;
• repair No. 2: 1.75 mm.

2. Install the cylinder head.
   • a) Carefully lower the cylinder head onto the cylinder block dowels.

Note: the cylinder head weighs more than 23 kg.

• b) Lubricate the threads and under the bolt heads with engine oil.
• c) Install the bolts and screw them in by hand.

• d) Tighten the cylinder head mounting bolts in the sequence shown in the figure.

Tightening torques:

• first stage: 70 N·m;
• second stage: loosen by 180°;
• third stage: 60 N·m;
• fourth stage: 60 N·m;
• fifth stage: turn a further 90°;
• sixth stage: turn a further 90°.

3. Install the injectors.
4. Install the pushrods.

Note: the pushrods must be installed in the places from which they were removed.

• a) Install the pushrods in the tappet recess.

• b) Lubricate the end of the pushrod with engine oil.

5. Install the rocker arms as an assembly.

Note: all rocker arm parts must be installed in the places from which they were removed.

• a) Screw the adjusting screws in fully, then screw in the locknut.

• b) Lubricate the rocker arm shafts with engine oil.
• c) Install the shafts in the rocker arms.

• d) Install the rocker arms on the support.

Note: do not confuse the intake and exhaust valve rocker arms.

• e) Install the valve bridges in the places from which they were removed.
• f) Install the rocker arms with supports assembled in the places from which they were removed.

• g) Screw in the support mounting bolts. Tightening torque: 36 N·m.

6. Install the intake manifold.
   • a) Install the intake manifold and screw in the bolts. Apply threadlocker (No. 3824041) to the bolts before installation.
   • b) If the intake manifold was installed with a gasket, replace the gasket with a new one.
   • c) If the intake manifold was mounted on RTV sealant, remove the old sealant and apply new (No. 3164070). Tightening torque: 24 N·m.
7. Install the cylinder head cover.
   • a) Install the cylinder head cover.
   • b) Tighten the screws. Tightening torque: 9 N·m.
8. Install the fuel rail.
9. Install the fuel return pipes.
10. Install the high-pressure fuel pipes.
11. Install the coolant bypass pipe.
12. Install the thermostat housing.
13. Install the exhaust manifold.
    • a) Apply high-temperature anti-seize compound to the exhaust manifold mounting bolts.
    • b) Install the exhaust manifold, new gaskets, spacers and retaining plates.
    • c) Tighten the exhaust manifold mounting bolts in the sequence shown in the figure. Tightening torque: 53 N·m.

14. Install the turbocharger.
15. Install the auxiliary drive belt.
16. Connect the air compressor cooling pipes to the cylinder head.
17. Connect the wires to the battery.
18. Fill with coolant.
19. Start the engine and make sure there are no leaks.