5.14.4. Dismantling, repair and assembly 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 or replacement of saddles of valves. The head of the block is replaced 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.
It will be required to you: a hexagon "on 8", a key "on 10", devices for compression of valvate springs and grinding in of valves.
1. Disconnect a wire from the minus plug of the rechargeable battery.
2. Remove a head of the block of cylinders (see. "Replacement of laying of a head of the block of cylinders").
3. Remove an inlet pipe (see. "Replacement of laying of an inlet pipe").
4. Remove a final collector (see. "Replacement of laying of a final collector").
5. Turn out bolts 1 and remove a back cover 2 heads of the block. Remove laying of a cover.
6. Take a hydropusher from a nest of a head of the block of cylinders.

Good advice
It is more convenient to take out hydropushers by means of a magnet or a sucker.

It is impossible to interchange the position of hydropushers therefore before removal they need to be marked that at assembly to establish on the places. It is necessary to store hydropushers in the same situation in what they are utanovlena on valves that from them oil did not flow out.

7. Install the device for compression of springs of valves on a block head (see. "Replacement of oil scraper caps of valves"). Having squeezed springs of valves by means of adaptation, take out valve crackers. Then, gradually weakening pressing adaptation handle, completely unclench valve springs. Remove adaptation from a block head. Take out a plate of valve springs. Then take out external and internal springs of the valve.
8. Remove a special stripper (see. "Replacement of oil scraper caps of valves") oil scraper cap of 1 valve.
9. Hook the screw-driver and take out a basic washer of 1 springs of valves.
10. Take out the valve from the combustion chamber.
11. Similarly take other valves.

Before removal mark all valves that at assembly to install them on former places.

12. After dismantling of a head of the block of cylinders wash out all details in gasoline, wipe and dry them. Clear combustion chambers and valves of a deposit.
13. Clear the internal surfaces of the directing plugs of valves a thin cylindrical brush from the copper wire clamped in an electric drill cartridge.
14. Remove from a head prileganiye surface to the block of cylinders the burned remains of sealing laying.
15. After cleaning examine a block head not to allow its operation with damages of carving openings, cracks (especially between saddles of valves and in final channels), corrosion, inclusions of alien materials, sinks and fistulas.
16. Check gaps between the directing plugs and valves. The gap is calculated as a difference of diameters of an opening in the plug and a valve core. Maximum permissible gap of 0,2 mm. If the gap exceeds the specified value, replace the valve and the directing plug. The old plug is pressed off by means of a mandrel from the combustion chamber. Install new plugs with the lock rings which are put on them against the stop of a lock ring in a block head surface from an opening under hydropushers. Before installation of the plug it is necessary to cool up to –40...–45 °C, and the head of the block should be heated to temperature of +160... +175 °C. The plug has to be inserted into a block head freely or with insignificant effort. In spare parts the directing plugs of valves deliver three repair sizes: the 1st repair size — with the outer diameter of the plug increased by 0,02 mm; the 2nd — the outer diameter of the plug is 14,2+0,053 - 0,040 mm; the 3rd — with the increased diameter at 0,02 mm of the 2nd size. At installation of plugs of the 1st repair size the opening under the plug in a head of the block does not need to be chiseled. At installation of plugs of the 2nd and 3rd repair sizes it is necessary to chisel an opening to diameter of 14,2+0,023 - 0,050 mm. After installation of new plugs develop in them an opening under valves to the sizes specified in tab. 5.1.

Table 5.1 the Nominal and maximum permissible sizes and landing of the interfaced details of a head of the block of cylinders of the engine of fashion. ZMZ-409.10

It is necessary to replace the directing plugs of valves in the car service equipped with the special equipment.

17. Check by means of a metal ruler and probes whether planeness of a surface of a head adjacent to the block is broken. For this purpose put a ruler an edge on a surface of a head of the block of cylinders in the middle, lengthways and then across, and then measure by the probe a gap between a surface of a head and a ruler. If the gap exceeds 0,1 mm, replace a head.
18. Check gaps in bearings of camshafts (see. "Removal, troubleshooting and installation of camshafts").
19. Check gaps between hydropushers of valves and channels under hydropushers in a block head. The gap is calculated as a difference of diameters of the channel and a hydropusher. Nominal diameter of the channel under a hydropusher of 35,0+0,025 mm, maximum permissible – 35,1 mm. Nominal diameter of a hydropusher is 35,0+0,025 - 0,041 mm, maximum permissible – 34,95 mm. Maximum permissible gap of 0,15 mm. If the gap exceeds the specified value, replace a hydropusher. If it does not yield positive result, replace a block head.
20. Examine valves. At detection on a working facet of the valve of cracks, a buckling of a head of the valve, a burn-out, deformation of a core it is necessary to replace the valve. Insignificant risks on a working facet of the valve can be removed grinding in (see. "Grinding in of valves").
21. Check a condition of springs of valves. Bent and with cracks of a spring replace.
22. 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.
23. Check for existence of deformations flanges for an inlet pipe and a final collector, replace the deformed details.
24. Repair the damaged carving openings a carving pro-race taps or installation of the repair plug (vvertysh).
25. Check a condition of saddles of valves. On working facets of saddles there should not be wear tracks, sinks, corrosion and so forth. 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").
26. More major defects of saddles of valves eliminate with grinding. Saddles need to be ground in a specialized workshop as special tools and the equipment for this purpose are required. If major defects of saddles do not manage to be eliminated with grinding, replace saddles.

Fig. 5.9. ZMZ-409.10 engine valve saddle profile: And – a saddle of the inlet valve; In – a saddle of the final valve

When grinding sustain the saddle sizes specified fig. 5.9. After grinding check a saddle facet beating concerning an opening in the directing valve plug, a maximum permissible beating of 0,05 mm. After grinding grind in valves. Then carefully clear and blow compressed air a block head that in the channels closed by valves and in combustion chambers there is no abrasive particle left. It is necessary to consider that after the saddle is proshlifut, the valve sits down in it more deeply therefore after grinding it is necessary to measure distance between an end face of a core of the valve pressed to a saddle and a camshaft axis. If this distance is less than 35,5 mm, replace a block head, otherwise normal work of hydropushers of valves is broken.
27. Check coaxiality of an arrangement of a plate of the valve and a saddle: apply on a valve head facet a paint coat (for example, the Berlin azure), insert it into the directing plug and, having slightly pressed to a saddle, turn. In the wake of paint on a facet of a saddle it is possible to judge coaxiality of an arrangement of the valve and a saddle.
28. Check a state the protocheck of a core of the valve under crackers. At detection of traces of a vykrashivaniye of edges the protocheck and wear of a cylindrical part replace the valve.
29. Replace oil scraper caps irrespective of their state.
30. Check a condition of plates of springs. Replace plates with considerable wear of basic flutes under springs.
31. Establish all removed details and knots of a head of the block of cylinders in the sequence, the return to removal.

Check tightness of the valve, for this purpose install it in a block head together with springs and crackers. After that put a block head on one side and fill in kerosene to the canal closed by the valve. If within 10 min. kerosene does not filter into the combustion chamber, the valve is considered tight.

32. Always replace new laying of a head of the block of cylinders, an inlet pipe (receiver) and a final collector as externally not damaged laying removed from the engine even can be strongly pressed out and will not provide tightness of consolidation.