Cylinder Head Bolt Tightening Sequence
Removal
1. Disconnect the battery from ground.
2. Remove the chains.
3. Remove both camshafts.
4. To facilitate removal of the head, 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 filter (see subsection 6.1.2). 7. On carburetor engines, perform the following work:
- disconnect the fuel hoses from the fuel pump;
- disconnect the throttle cable;
- disconnect the wiring connectors from the carburetor;
- disconnect the brake booster, cooling system, crankcase exhaust and other hoses from the corresponding valves and cylinder head pipes;
- remove the intake manifold stand;
- on vehicles equipped with a catalytic converter, disconnect the connector from the oxygen sensor.
8. On injection engines, perform the following work:
- perform fuel system decompression procedures and disconnect the fuel hoses from the fuel distributor;
- disconnect the throttle cable;
- disconnect the wiring connectors from the throttle body, intake manifold and other parts and assemblies;
- disconnect the brake booster, cooling system, crankcase exhaust and other hoses from the corresponding valves and cylinder head pipes;
- remove the manifold stand;
- 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 in the front left corner of the cylinder head.
11. Working in the reverse order to that shown in Fig. Cylinder Head Bolt Tightening Sequence, loosen all ten main cylinder head bolts. Loosen the bolts in several steps, 1/2 turn at a time, until the bolts can be loosened by hand.
12. Remove the bolts and washers, paying attention to their orientation.
13. Working with two people, remove the cylinder head, gasket, dowel pins and oil jet (if the fit of the pins and the nozzle has weakened).
14. If the head is to be disassembled for major repairs, then follow the description in section 3.1.2.6.
Preparing for assembly
1. Check the condition of the cylinder head bolt threads, regardless of the reason for removing the head. It is recommended to replace the bolts each time the cylinder head is removed.
2. Clean the split surfaces of the head and block, closing all openings to prevent dirt from getting in. Cover the gaps in the pistons with grease, which is then removed.
3. Check for damage on the separating surfaces of the cylinder head and block (deep scratches, chips, etc.). Minor damage can be removed with a file, but serious damage can only be removed by sanding.
4. Check the deformation of the separating surfaces of the head and block.
Installation
1. Wipe dry the separating surfaces of the head and cylinder block. Make sure that the guide pins are present on both sides of the cylinder block plane and insert the oil nozzle into the center of the block.
2. Place a new gasket on the cylinder block, aligning the holes in the gasket with the pins and oil nozzle.
3. With the help of an assistant, carefully install the head onto the cylinder block, aligning the head with the guide pins.
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4. Lubricate the threads and the bottoms of the bolt heads with clean oil.
5. Place washers on the bolts so that the conical surface of the washers faces away from the bolt head.
6. Carefully insert the bolts into the corresponding holes in the head (do not drop the bolts), tighten them by hand.
7. Tighten cylinder head bolts 1–10 in the sequence shown (see Fig. Cylinder Head Bolt Tightening Sequence) with the torque of the 1st stage of tightening. Do not tighten bolts 11–15 with M6 thread yet.
8. Tighten the bolts to Stage 2 torque.
9. After a minute, loosen the bolts in the reverse order shown in Fig. Cylinder Head Bolt Tightening Sequence. Loosen the tightening gradually, 1/2 turn at a time, until the bolts can be turned by hand.
10. Tighten the bolts in sequence to the 3rd stage tightening torque.
11. Tighten the bolts to the 4th stage tightening angle or tighten with a torque wrench to the 4th stage torque.
12. Tighten the M6 bolts (bolts 11–15) in sequence to the specified torque.
13. Connect the cooling system hoses.
14. Perform the following operations:
- reconnect the removed wiring, hoses and cables to the intake manifold;
- connect the throttle cable;
- connect the exhaust pipe, exhaust gas sensor connector (if provided);
- install the air filter and duct.
15. Install the camshafts (see subsection 3.1.1.10).
16. Install the chains and sprockets.
Caution! If the cylinder head has been overhauled, 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 warm it up. Check the valve clearances on a warm engine (see subsection 3.1.1.9).