Comment. If the engine has been overheating frequently, it is likely that the cylinder head may have warped, carefully check for signs of head deformation.
Cleaning
2. Clean the split planes of the cylinder head.
3. Clean the combustion chambers, all holes and channels from carbon deposits, then flush the cylinder head with a solvent.
4. Remove massive carbon deposits from valves.
Examination
Comment. Before concluding that parts need to be resurfaced, be sure to perform all the checks described below.
cylinder head
5. Carefully inspect the head, check for cracks, traces of coolant penetration and other damage. If cracks are found, replace the cylinder head.
6. Check the deformation of the split plane of the cylinder head (see photo). If a curvature of the split plane is found, then the head should be replaced (not to be polished).
7. Check the condition of the valve seats. In the presence of pitting (fossae), cracks, traces of burnout, head repair will be required in a car service workshop. Minor defects can be removed by lapping the valve.
8. Check the wear of the guide bushings (bushing wear is one of the causes of bluish smoke from the exhaust pipe).. To do this, insert the valve into the corresponding guide sleeve and rock it from side to side. A small, barely perceptible play is acceptable. If there is significant valve play in the sleeve, then measure the valve diameter. If the valve diameter has noticeably decreased due to wear, replace the valve. If the valve stem diameter is correct, replace the guide bushing (carried out in a car service workshop). It is also recommended to check the gap between the bushing and the valve, by the difference between the measured inner diameter of the bushing and the diameter of the valve. New bushings are pressed in after deep cooling. The protrusion of the bushings above the cylinder head is specified in the Technical data.
9. If the guide bushings will change, then the valve seats should be reground (or ream) only after pressing in new bushings.
valves
10. Check up presence on valves of cracks, traces of a burn-out, scuffs and the shoulder which was formed owing to wear on cores. Check the bend. Valve by rolling on a smooth hard surface. Check the wear at the end of the rod. If any signs of wear or damage are found, replace the valve.
11. If as a result of this check it turns out that the condition of the valve is satisfactory, then measure the diameter of the valve in several places (see photo). A noticeable difference in diameter indicates valve stem wear. If a noticeable difference in diameter is found in at least two places, replace the valve.
12. If the condition of the valves is satisfactory, then they should be lapped to the seats. If the saddles have only minor damage, or the seat has been re-grinded, then lapping can be done on a fine composition. A coarse lapping compound should be used only if traces of deep wear or severe burnout of the seats are found. In this case, the cylinder head and valves should be checked by an experienced technician to determine whether the seats need to be re-sinked or replaced.
13. Before lapping, lay the cylinder head on a flat surface, with the combustion chambers up.
14. Apply a thin coat of lapping paste to the seat bevel. Lapping is carried out by turning the device 180°in both directions and periodically lifting the valve to evenly redistribute the abrasive material (see photo).
15. Lapping on a coarse composition ends after the formation of a monotonous matte belt on the chamfers of the valve and seat (see photo). Wipe the valve and seat free of paste residue and continue lapping on a fine compound. Lapping is considered complete when a uniform, continuous grayish band forms on the chamfers of the valve and seat. Further lapping is not allowed, as due to excessive wear of the seat, its subsequent repair may become impossible.
16. After grinding in all valves, thoroughly wash all parts with solvent.
Valve train parts
17. Check up presence on springs of traces of chipping and damages. A rough check of the condition of the spring can be done by comparing the removed spring with a new one.
18. Check the deviation of the spring from the vertical using a square and compare with the standard
19. On 1.6L single-shaft engines, bearings are built into the support washers of the exhaust valve springs to ensure valve rotation and protect the seat from carbon deposits. If the bearing seizes or is damaged, replace the thrust washer.
20. If at least one of the springs is damaged, has an increased deviation from the vertical, or has lost elasticity, then replace all the springs in the kit. Keep in mind that during a major overhaul, it is recommended to change the valve springs, regardless of their condition. Oil seals change regardless of their condition.
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