Note. When assembling the cylinder head, all valve stem seals must be replaced. Reassembly requires a valve spring compressor.
4-cylinder engine M43TU
1. Perform the operations indicated in p.p. 4-9.
2. Insert hydraulic rocker bearings, rocker arms and camshafts (chapter 2A).
3. Install the cylinder head as indicated in chapter 2A.
N42 engine and 6-cylinder engines
4. Lubricate the valve stems and insert the valves as they were before disassembly (pic. 8.4). If new valves are being installed, insert them into the seats to which they were lapped.
5. Dip the valve stem seal in the engine oil. Usually, new valve stem seals are fitted with a mandrel for installing them to prevent damage to the cap by the edges of the cracker groove. Place the mandrel on top of the valve stem and push the cap through the mandrel until it is seated on the guide bushing with a tube of suitable diameter. If there are no mandrel caps included, wrap tape around the top of the stem to protect the cap as it passes through the groove (pic. 8.5, a, b).
6. Install the spring seats (pic. 8.6, a, b).
7. Install the springs on the seats, then slide the top spring plate onto the stem (pic. 8.7, a-c). If the ends of the spring have different diameters, place the spring with the larger diameter down (to the cylinder head).
8. Compress the springs with a tool and insert crackers into the groove of the rod. Release the device. Repeat this operation for the rest of the valves.
9. After installing all valves, support the head with two blocks of wood and tap with a hammer through the block of wood on the ends of all valves so that the parts of the valve mechanisms fall into place.
10. Install the camshaft bearings, rocker arms and camshafts as indicated in chapter 2B.
11. Reinstall the cylinder head (chapter 2B).