4.20. 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 as it is described in subsection «Replacement of a lining 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, replacement of directing plugs of valves, replacement or polishing of saddles of valves. At such malfunctions as infringement of tightness of channels of a shirt of system of cooling and коробление привалочной surfaces to the block of cylinders, replace a block head.

It be required to you: keys «on 13», «on 17», «on 21», a candle key, a screw-driver, круглогубцы (tweezers), the adaptation for compression клапанных springs.

1. Disconnect from a branch pipe on a receiver a hose of a regulator of pressure of fuel.	2. Turn away a nut of fastening of a receiver to an inlet pipe and...

3.... Remove a receiver and the lining established under it.

THE NOTE In the presence of the adaptation for compression клапанных the springs, different on a design from shown (for example, screw, rolled in an aperture in a block head under a hydrosupport), probably, a receiver it is not required to remove. For convenience of work it is possible to remove an inlet pipe and a final collector (Replacement of a lining of an inlet pipe and a final collector »), and also other hinged knots removed together with a head, however, see« if repair or replacement of these knots is not required, at sufficient skill to repair a block head it is possible and without removing them.

4. Turn out all spark plugs.	5. Establish on a head of the block the adaptation for compression клапанных springs, enclose under the valve a suitable emphasis (for example, a head from a tooling), compress springs and...

6.... Take crackers from a plate of springs.	7. Remove the adaptation, a plate of springs...

8.... Springs...	9.... A basic washer internal and...

10.... External springs.

11. Take out the valve from the directing plug.

12. In the same way remove other valves.

13. Collect a head of the block of cylinders in an order, the return to dismantling, using the new or prochecked details. Replace all linings new.

It be required to you: a micrometer, a calliper, a ruler.

1. Remove a deposit from combustion chambers.

GOOD ADVICE Preliminary soak a deposit kerosene. Mechanical clearing of a deposit is possible. Be careful – avoid to inhale a dust formed at cleaning of chambers of combustion. For prevention of formation of a dust periodically moisten a deposit with kerosene.

2. Examine a head. If there is a suspicion on presence of cracks in a head of the block of cylinders (especially at hit of a cooling liquid in картер or oils in cooling liquid), check up tightness of a head of the block at the special stand (in the repair shops having the corresponding equipment).

3. Check up a condition of saddles of valves. On working facets of saddles there should not be wear tracks, bowls, corrosion, etc. can replace Saddles of valves in a specialised workshop. Insignificant damages (and so forth) can be deduced small risks, scratches grinding in of valves («Grinding in of valves» see).

4. More major defects of saddles of valves eliminate polishing. Saddles are recommended to be ground in a specialised workshop as special tools and the equipment for this purpose are required.

5. Remove a deposit from valves and examine them. Deformation of a core of the valve and a crack on its plate are not supposed. In the presence of damages replace the valve. Check up, 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 supposed. After grinding the corner of a facet concerning a plate plane should be 45°30’±5 ’, and the thickness of a cylindrical part of a plate should be not less than 0,5 mm. Besides, at the final valve the layer of an alloy put on a facet should remain.

6. Measure diameters of cores of valves. Diameter of a core of all valves should be 7,985–8,000 mm.

7. Measure diameter of an aperture in directing plugs, define calculation a backlash between cores of valves and plugs. Internal diameter of plugs should be:

– For inlet valves of 8,022-8,040 mm;

– For final valves of 8,029-8,047 mm.

It is supposed to define diameter in calibre (checkpoint/not checkpoint), as shown.

Assembly backlash for new plugs and valves:

– For inlet valves of 0,022-0,055 mm;

– For final valves of 0,029-0,062 mm.

As much as possible admissible backlash (at deterioration) – 0,15 mm.

8. Maslosemnye caps replace irrespective of their condition.

9. Examine levers of valves. On the surfaces interfaced to a core of the valve, with a cam of a camshaft and with the spherical end of an adjusting bolt, the tease and risks are not supposed. In the presence of damages replace levers.

10. Examine springs of valves. Cracks and decrease in elasticity of springs are not supposed. If necessary replace springs.

At possibility define elasticity of springs on their deformation under loading. According to technical requirements for an external spring:

– Height in a free condition of 50 mm;

– Height under loading 283,39±14,7 Н (28,9±1,5 кгс) – 33,7 mm;

– Height under loading 452,06±22,55 Н (46,1±2,3 кгс) – 24 mm.

For an internal spring:

– Height in a free condition of 39,2 mm;

– Height under loading 136,30±6,86 Н (13,9±0,7 кгс) – 29,7 mm;

– Height under loading 275,55±13,73 Н (28,1±1,4 кгс) – 20 mm.

11. Clear привалочную a surface of a head of the rests of a lining and...	12.... Check up planeness of this surface. For this purpose put a metal ruler an edge on a head surface in the middle along a head axis, and then on diagonals and щупом measure a backlash between a plane of a head and a ruler. Replace a head if the backlash exceeds 0,1 mm.

13. A lining of a head of the block of cylinders always replace new as removed from the engine even the outwardly not damaged lining can appear strongly pressed out and will not provide tightness of consolidation.

If the increased backlashes between directing plugs and cores of valves («Defektovka of details of a