2. Clean carbon deposits from the combustion chamber and cylinders, then wash the cylinder head with a suitable solvent.
3. Clean the passages in the cylinder head using a wire brush.
4. Carefully inspect the head for cracks and other damage. If there are cracks on the head, it must be replaced.
5. Using a metal ruler and feeler gauge, check the flatness of the mating surface of the head.
6. Valve seats with signs of wear or burning must be processed with the mandatory preservation of the angles and chamfer size.
7. If the valve seat must be machined, determine the maximum amount of metal that can be removed. If too much metal is removed, the hydraulic lifters will not function properly.
8. Insert the valve into the guide and press it against the valve seat. Measure the distance (a) from the end of the valve stem to the top surface of the cylinder head. The minimum allowable distance is 33.8 mm for intake valves and 34.1 mm for exhaust valves. If the valve seat is excessively worn, machining is not allowed and the cylinder head must be replaced.
(The original article is available at www.VWManual.ru)
9. After any treatment of the valve seats, it is necessary to grind them in.
10. Check the internal diameters of the valve guides. If the values exceed the maximum permissible value, the valve guides should be replaced in a special repair shop.
Warning: Replacing the guide also requires regrinding the seat of the corresponding valve.
11. Inspect each valve head for pitting, burning, cracks and general wear.
12. If the valve is in good condition, measure the valve stem diameter at several points using a micrometer. Any significant difference in the obtained valve stem measurement data indicates stem wear. In this case, the valve must be replaced.
13. If the valves are in satisfactory condition, they need to be ground in. The valves need to be ground in using only fine-grained polishing paste. Lubricate the surface of the valve seat with a small amount of paste and install the valve in the corresponding seat. Press the rubber suction cup tightly to the valve plate and rotate the valve in one direction or the other.
14. After finishing the grinding process, thoroughly clean all parts from dirt and paste. Check the valve seat and plate. A solid matte ring should be visible on both parts, which indicates the width of the valve chamfer.
15. Check the valve springs for wear and delamination, and measure their free length. If possible, compare each of the existing springs to the new spring.
16. Place the springs on a flat horizontal surface and check their deviations from the horizontal position. If at least one of the springs is damaged, replace all the springs in the set.
17. Check the condition of the valve crackers, as well as the cracker installation locations on the valve. If there are any defects, the damaged parts must be replaced. The oil-deflecting caps must be replaced each time they are removed.
18. Check valve train components and hydraulic lifters.
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