Cylinder head height measurement location and reground head sign
h – height of cylinder head,
a – location of the reground head sign,
R – reground head symbol
Valve guide bushing dimensions
Valve seat dimensions
Comparison of valve seats on early and late models
a - old type,
b – new type,
1 – valve seats
1. Remove the cylinder head.
2. Gradually loosen the camshaft bearing caps.
3. Remove the bearing caps, marking the direction of their attachment.
4. Remove the sealing ring located at the end of the camshaft.
5. Remove the camshaft.
6. Mark and remove the valve lifters.
7. Using a special clamp, remove the valves together with their springs and arrange them in order.
8. Remove the swirl chambers by knocking them out through the nozzle hole.
9. Clean the cylinder head. A special cleaning agent should be used to clean the connection surface "Decaploc 88".
10. Check the flatness of the surface of the connection with the engine cylinder block (maximum flatness 0.07 mm).
11. If necessary, the cylinder head should be reground. To do this, follow these steps:
- regrind the valve seats to obtain the required stroke;
- replace the swirl chambers with swirl chambers of repair dimensions and achieve the required value of their protrusion;
- install 0.4 mm thick compensating gaskets under the valve springs.
12. Check the condition of the valve guides. If necessary, replace them. This operation should be performed by a qualified specialist. Replacing the valve guides requires mandatory regrinding or replacement of the corresponding valve seats.
13. Check the condition of the valve seats. If necessary, they should be reground or replaced. This operation should be performed by a qualified specialist.
14. Check the condition of the springs and camshaft.
15. Check the protrusion of the swirl chambers (0–0.03 mm).
16. If necessary, the required size should be achieved by processing the surfaces "x" and "y" of the vortex chambers (see picture Comparison of valve seats on early and late models).
17. Check the valve chamfers.
18. If necessary, the required dimensions should be achieved by grinding the valve seats.
19. Grind the valves.
20. Install the valves.
Attention! If the cylinder head has been reground, then 0.4 mm thick compensating gaskets should be installed under the valve springs.
21. Install 2.425 mm thick plates on the valve stems and check that the plates exceed the spring retainers.
22. If the plates do not exceed the spring plates, then the upper surfaces of the plates should be ground down.
23. Install the pushers.
24. Lubricate the camshaft bearings with oil.
25. Install the camshaft with the "DIST" mark toward the timing drive.
26. Install the bearing caps and gradually tighten them to a torque of 17.5 Nm.
27. Install the cylinder head.