5.9.4. Dismantling, repair and assembly of a head of the block of cylinders

If repair of a head of the block of cylinders of the engine established 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, polishing of saddles of valves. At such malfunctions as violation of tightness of channels of a shirt of system of cooling and a buckling of a privalochny surface to the block of cylinders, replace a head of the block.

It 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 maslosjemny caps (see. «Replacement of maslosjemny 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. Unscrew 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. Unscrew eight nuts of fastening of a final collector and remove it from hairpins.

Note Sealing laying of an inlet pipe and collector at each dismantling replace new.

6. Turn out three bolts of fastening...	7.... also remove an arm of the coil of ignition 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 a gear pulley of a camshaft, holding a pulley from a provorachivaniye the special adaptation. In the absence of the adaptation it is possible to use пассатижами with a screw-driver: insert handles passatizhy into pulley openings, and a screw-driver keep them from a provorachivaniye...	11.... also remove a pulley.

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

14.... also take the hydrojack.

15. Similarly remove other yokes and take girokompensator.

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

18.... also take a 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 прогара in combustion chambers, replace a head. Remove agnails and забоины on the plane of a head of the block.

20. Check planeness of the 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 shchupy 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 the final collector, the deformed head replace.

23. The damaged carving openings repair carving pro-race by taps or installation of the repair plug (ввертыша).

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 mines goes down at 15-20, means, in a head there are cracks and it is necessary to replace it. 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 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 during 3 mines 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 under the removed valve a suitable emphasis.

30. Establish the adaptation for compression of springs of valves and compress with its help of a spring of the valve. A screw-driver or tweezers take out crackers.

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

32. Mark valves numbers of cylinders, for example накерните.

33. Take the valve from a block head.	34. The special adaptation remove a maslosjemny cap (see. «Replacement of maslosjemny caps»).

Note The Maslosjemny cap is executed for a single whole with the bottom plate of a spring of the valve.

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 (in the repair shops having the corresponding equipment) is allowed. After grinding concerning the plane of a plate inlet ±5 valves 45°30 should have a facet corner’ with width of a corbel after grinding in on a facet of the valve of 1,75-2,32 mm, and at final valves – 45,5°30 ’±5’ with width of a corbel of 1,44-1,54 mm. Insignificant risks and scratches on a facet can be deduced valve grinding in 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: put on a facet of a head of the valve a thin layer of graphite of a pencil slate pencil, insert the valve into 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 on fig. 5.6. Nominal and maximum permissible diameters of cores of valves are specified in tab. 5.5.

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

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

42. If a gap more admissible, repair plugs expansion till the repair size with increase in diameter of an opening at 0,04 mm of rather nominal diameter. Thus in them it is necessary to establish valves of the corresponding repair size with providing a nominal gap in interface. Develop openings of plugs, using a set of development with a directing shaft. In order to avoid a vykrashivaniye of a surface of the plug a layer of removed metal at each pass and giving of the tool should be minimum. Otherwise replace directing plugs. The nominal and repair sizes of 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. It is possible to replace saddles of valves in a specialized workshop. Insignificant damages (etc.) can be deduced small risks, scratches grinding in of valves (see. «Grinding in of valves»).

44. More major defects of saddles of valves eliminate with polishing, maintaining the sizes for inlet ±5 valves 45°30’ with width of a corbel after grinding in on a facet of the valve of 1,75-2,32 mm, and for final valves – 45,5°30 ’±5’ with width of a 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 polishing did not give the necessary result, replace saddles of valves. The nominal and repair sizes are specified in tab. 5.7.

45. Replace maslosjemny caps irrespective of their condition.

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

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