If repair of a head of the block of cylinders of the engine installed on the car is necessary remove it (see. "Replacement of laying of a head of the block of cylinders"). In most cases repair of a head of the block of cylinders consists in grinding in or replacement of valves, grinding of saddles of valves. At such malfunctions as violation of tightness of channels of a shirt of the cooling system and a buckling of a privalochny surface to the block of cylinders, the head of the block is replaced.

It will be required to you: the same tools, as for replacement of laying of a head of the block of cylinders (see. "Replacement of laying of a head of the block of cylinders") and oil scraper caps (see. "Replacement of oil scraper caps"), and also keys "on 13", "on 19".

1. Remove a head of the block of cylinders (see. "Replacement of laying of a head of the block of cylinders").

2. Turn off six nuts of fastening of an inlet pipe to a head of the block of cylinders and remove an inlet pipe assembled with throttle knot.

3. Turn out three bolts of fastening...	4.... also remove the thermoscreen.

5. Turn off eight nuts of fastening of a final collector and remove it from hairpins.

Note Replace sealing laying of an inlet pipe and a collector at each dismantling new.

6. Turn out three bolts of fastening...	7.... also remove an ignition coil arm assembled with the phase sensor.

8. Turn out three bolts of fastening...	9.... also remove the thermostat case.

10. Turn out a bolt of fastening of the cogged pulley of the camshaft, holding a pulley from a provorachivaniye special adaptation. In the absence of adaptation it is possible to use passatizha with the screw-driver: insert handles passatizhy into pulley openings, and the screw-driver keep them from a provorachivaniye...	11.... also remove a pulley.

12. Turn off a fastening nut...	13.... remove from a hairpin a yoke with the holder...

14.... also take the hydrocompensator.

15. Similarly remove other yokes and take girokompensator.

16. Turn out two bolts of fastening...	17.... remove a persistent flange...

18.... also take the camshaft from a body of a head of the block of cylinders.	19. Clear combustion chambers of a deposit. Examine a head of the block of cylinders. If on it there are cracks or traces of a progar in combustion chambers, replace a head. Remove agnails and zaboina on the block head plane.

20. Check planeness of a surface adjacent to the block of cylinders. For this purpose put a ruler an edge on a head surface at first in the middle lengthways, and then on diagonals and measure by the probe a gap between the plane of a head and a ruler. Replace a head if the gap exceeds 0,15 mm.

21. Clear of the remains of laying and a deposit of a surface of flanges of a head for installation of an inlet pipe and a final collector.

22. Check existence of deformations of flanges for an inlet pipe and a final collector, replace the deformed head.

23. Repair the damaged carving openings a carving pro-race taps or installation of the repair plug (vvertysh).

24. Check density of installation of caps of a shirt of cooling. When weakening their landing restore it stamping.

25. For check of tightness of a head of the block muffle an opening in a head under a thermostat nest. It can be made, for example, having established deaf laying from a dense cardboard under the case of the thermostat and having wrapped bolts of its fastening.

26. Fill in kerosene to canals of a water shirt. If kerosene level at endurance 15–20 min. goes down, so in a head there are cracks and it should be replaced. After check do not forget to remove cardboard laying.

27. Check a condition of basic surfaces under shaft necks in a block head. If at least on one of them there are wear tracks, teases or deep risks, grind necks of bearings and measure diameter of necks. If diameter of necks is more specified (see tab. 5.2 and tab. 5.3), replace a block head.

28. For check of tightness of valves fill in kerosene to inlet and final canals of a head. If within 3 min. kerosene does not filter from channels into combustion chambers, valves are tight. Otherwise grind in (see. "Grinding in of valves") or replace valves.

29. Establish a suitable emphasis under the removed valve.

30. Install the device for compression of springs of valves and squeeze valve springs with its help. The screw-driver or tweezers take out crackers.

31. Take out the top plate and a spring of the valve. Similarly take out crackers, plates and springs of other valves.

32. Mark valves numbers of cylinders, for example to a nakernita.

33. Take the valve from a block head.	34. Special adaptation remove an oil scraper cap (see. "Replacement of oil scraper caps").

Note The oil scraper cap is executed for a single whole with the lower plate of a valve spring.

35. Remove a deposit from valves and examine them. Deformation of a core of the valve and a crack on its plate are not allowed. In the presence of damages replace the valve.

36. Check whether it is not too worn-out and whether the working facet is damaged. Grinding of a working facet of valves is allowed (in the repair shops having the corresponding equipment). After grinding concerning the plane of a plate inlet valves 45 °30 '±5 have to have a facet corner’ with a corbel width after grinding in on a facet of the valve of 1,75-2,32 mm, and at final valves – 45,5 °30 '±5’ with a width of corbel of 1,44-1,54 mm. Insignificant risks and scratches on a facet can be removed grinding in of the valve to a saddle (see. "Grinding in of valves").

Prevention In order that on cores of valves risks were not formed, do not clear them wire brushes and metal scrapers.

37. Check concentricity of an arrangement of a plate of the valve and a saddle: apply a thin film of graphite of a pencil slate pencil on a valve head facet, insert the valve into the directing plug and, having slightly pressed to a saddle, turn.	38. In the wake of graphite on a facet of a saddle it is possible to judge concentricity of an arrangement of the valve and a saddle.

Fig. 5.6. Zones of wear of the valve: 1 – zone of the smallest wear of a core; 2 – core end face; 3 – a pro-point under crackers; 4 – zones of the greatest wear of a core; 5 – working facet; 6 – plate edge

39. Check wear of a core of the valve in the places shown in fig. 5.6. Nominal and maximum permissible diameters of cores of valves are specified in tab. 5.5.

40. Check a state the protocheck 3 (see fig. 5.6) a valve core under crackers. At detection of traces of a vykrashivaniye of edges the protocheck and wear of a cylindrical part replace the valve.

41. Check a condition of the directing plugs of valves, having measured the internal diameter of an opening of the plug, diameter of a core of the valve and having determined a gap by a difference of these sizes. Gaps are given in tab. 5.5.

42. If the gap is more than admissible, repair plugs expansion to the repair size with increase in diameter of an opening by 0,04 mm of rather nominal diameter. At the same time in them it is necessary to install valves of the corresponding repair size with providing a nominal gap in interface. Develop openings of plugs, using a set of development with the directing shaft. In order to avoid a vykrashivaniye of a surface of the plug a layer of the removed metal at each pass and giving of the tool have to be minimum. Otherwise replace the directing plugs. The nominal and repair sizes of the directing plugs of inlet and final valves are specified in tab. 5.6.

43. Check a condition of saddles of valves. On working facets of saddles there should not be wear tracks, sinks, corrosion, etc. Saddles of valves can be replaced in a specialized workshop. Insignificant damages (small risks, scratches, etc.) can be removed grinding in of valves (see. "Grinding in of valves").

44. More major defects of saddles of valves eliminate with grinding, maintaining the sizes for inlet valves 45 °30 '±5’ with a corbel width after grinding in on a facet of the valve of 1,75-2,32 mm, and for final valves – 45,5 °30 '±5’ with a width of corbel of 1,44-1,54 mm. Saddles are recommended to be ground in a specialized workshop as special tools and the equipment for this purpose are required. If grinding did not yield the necessary result, replace saddles of valves. The nominal and repair sizes are specified in tab. 5.7.

45. Replace oil scraper caps irrespective of their state.

46. Examine springs of valves. Cracks and decrease in elasticity of springs are not allowed. At an opportunity determine elasticity of springs by the developed effort (tab. 5.8). And springs with cracks replace the bent springs (deformation in a free state more than 1,6 mm).

47. Always replace laying of an inlet pipe, a final collector and a head of the block of cylinders new, as removed, even externally not damaged laying can be strongly pressed out and will not provide tightness of consolidations.