Cylinder head — assembly (BMW 3 Series E46)

Note: When assembling the cylinder head, all valve stem seals must be replaced. A valve spring compressor is required for assembly.

4-cylinder engine M43TU

1. Perform the operations specified in paragraphs 4-9.

2. Insert the hydraulic rocker arm supports, rocker arms and camshafts (chapter 2A).

3. Install the cylinder head as shown in chapter 2A.

N42 engine and 6-cylinder engines

4. Lubricate the valve stems and insert the valves as they were before disassembly (Fig. 8.4). If new valves are being installed, insert them into the seats to which they were lapped.



5. Dip the first valve stem seal into engine oil. New stem seals usually come with a mandrel to prevent the edges of the seal groove from damaging the seal. Place the mandrel on top of the valve stem and push the seal through the mandrel until it seats on the guide bushing using a tube of the appropriate diameter. If the stem seal kit does not include a mandrel, wrap some tape around the top of the stem to protect the seal as it passes through the groove (fig. 8.5, a, b).





6. Install the spring seats (fig. 8.6, a, b).







7. Install the springs onto the seats, then place the upper spring plate onto the rod (fig. 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 the tool and insert the crackers into the groove of the rod. Release the tool. Repeat this operation on the remaining valves.



9. After installing all the valves, support the head with two wooden blocks and tap with a hammer through a wooden block on the ends of all the valves so that the valve mechanism parts fall into place.

10. Install the camshaft bearings, rocker arms and camshafts as shown in chapter 2B.

11. Install the cylinder head into place (chapter 2B).

[Original publication posted on the website «www.bmwman.ru»]