Cylinder Head

GENERAL INFORMATION

Cylinder Head Bolt Tightening Sequence

Removal

PROCEDURE

1. Disconnect the battery ground cable.

2. Remove the chains.

3. Remove both camshafts.

4. To make cylinder head removal easier, it is recommended to remove both manifolds (see subsection 6.1.12 and subsection 6.1.13).

5. Disconnect the exhaust pipe from the manifold.

6. Remove the air cleaner (see subsection 6.1.2).

7. On carbureted engines, perform the following: – disconnect the fuel hoses from the fuel pump; – disconnect the throttle cable; – disconnect the wiring harness connectors from the carburetor; – disconnect the brake booster vacuum hose, cooling system hoses, crankcase ventilation hoses and other hoses from the corresponding valves and cylinder head fittings; – remove the intake manifold bracket; – on vehicles equipped with a catalytic converter, disconnect the connector from the oxygen sensor.

8. On fuel-injected engines, perform the following: – relieve the fuel system pressure and disconnect the fuel hoses from the fuel distributor; – disconnect the throttle cable; – disconnect the wiring harness connectors from the throttle body, intake manifold and other components and assemblies; – disconnect the brake booster vacuum hose, cooling system hoses, crankcase ventilation hoses and other hoses from the corresponding valves and cylinder head fittings; – remove the manifold bracket; – on vehicles equipped with a catalytic converter, disconnect the connector from the exhaust gas sensor.

9. Disconnect the cooling system hoses from the cylinder head.

10. Remove the M6 bolt from the front left corner of the cylinder head.

11. Working in the reverse order of the sequence shown in the Cylinder Head Bolt Tightening Sequence figure, loosen all ten main cylinder head bolts. Loosen the bolts in several passes, by 1/2 turn per pass, until the bolts can be turned out by hand.

12. Remove the bolts and washers, noting their orientation.

13. With an assistant, remove the cylinder head, gasket, locating dowels and oil jet (if the dowels or oil jet have loosened in their seats).

14. If the cylinder head is to be disassembled for major repair, refer to the procedure in Section 3.1.2.6.

Installation

PROCEDURE

1. Inspect the threads of the cylinder head bolts regardless of the reason for removing the cylinder head. It is recommended to replace the bolts each time the cylinder head is removed.

2. Clean the mating surfaces of the cylinder head and block, covering all openings to prevent dirt from entering. Apply grease to the piston crowns, then remove it.

3. Inspect the mating surfaces of the cylinder head and block for damage (deep scratches, chips, etc.). Remove minor damage with a fine file. Serious damage must be removed by grinding only.

4. Check the mating surfaces of the cylinder head and block for distortion.

Installation

PROCEDURE

1. Wipe the mating surfaces of the cylinder head and block dry. Make sure the locating dowels are present on both sides of the block deck, and insert the oil jet into the center of the block.

2. Place a new gasket on the cylinder block, aligning the gasket holes with the dowels and the oil jet.

3. With an assistant, carefully install the cylinder head on the block, aligning the head with the locating dowels.

4. Apply clean engine oil to the bolt threads and the underside of the bolt heads.

5. Install the washers on the bolts so that the tapered surface of the washers faces away from the bolt head.

6. Carefully insert the bolts into the corresponding holes in the cylinder head (do not drop the bolts), and tighten them by hand.

7. Tighten cylinder head bolts 1–10 in the specified sequence (see the Cylinder Head Bolt Tightening Sequence figure) to the Stage 1 torque. Do not tighten the M6 bolts (bolts 11–15) yet.

8. Tighten the bolts to the Stage 2 torque.

9. After one minute, loosen the bolts in the reverse order of the sequence shown in the Cylinder Head Bolt Tightening Sequence figure. Loosen gradually, by 1/2 turn per pass, until the bolts can be turned out by hand.

10. Following the sequence, tighten the bolts to the Stage 3 torque.

11. Turn the bolts through the Stage 4 angle, or tighten them with a torque wrench to the Stage 4 torque.

12. Following the sequence, tighten the M6 bolts (bolts 11–15) to the specified torque.

13. Connect the cooling system hoses.

14. Perform the following operations: – connect the wiring, hoses and cables removed from the intake manifold; – connect the throttle cable; – connect the exhaust pipe to the muffler and the exhaust gas sensor connector (if equipped); – install the air cleaner and air duct.

15. Install the camshafts (see Subsection 3.1.1.10).

16. Install the chains and sprockets.

Warning: If a major repair of the cylinder head has been performed, check the valve clearances on a cold engine before installing the cylinder head cover (see Subsection 3.1.1.9).

17. Start the engine and allow it to warm up. Check the valve clearances on a warm engine (see Subsection 3.1.1.9).