5.9.2. Replacement of hydrojacks of gaps in the mechanism of a drive of valves

Hydrojacks of gaps in the mechanism of a drive of valves represent self-regulating support of the press levers transferring effort from a camshaft to valves, and carry out function of elimination of gaps in a drive.

Operation of the hydrojack is based on a principle of not compressibility of the engine oil which is constantly filling at operation of the engine an internal cavity of the hydrojack and moving its plunzher at emergence of a gap in a drive of the valve, providing continuous contact of the lever of a drive of the valve to a camshaft cam without a gap. Thanks to it need of adjustment of valves disappears at maintenance.

Practically all malfunctions of hydrojacks diagnose on the characteristic noise published by the gas-distributing mechanism on various power setting.

For replacement of hydrojacks the head of the block of cylinders can be not removed from the engine. It is enough to remove the camshaft case only. However after that it is recommended to replace laying of a head of the block surely new as the case of a camshaft and a head of the block are attached to the block by the same bolts and at a repeated inhaling of bolts old laying of a head of the block can not provide tightness of connection.

It be required to you: keys «on 10», «on 13».

Note Work carry out through 15–30 mines after an engine stop that pressure of oil in hydrojacks decreased.

1. Uncover heads of the block of cylinders (see. «Replacement of laying of a cover of a head of the block of cylinders»).	2. Unscrew a fastening nut...

3.... remove from a hairpin a yoke with the holder...	4.... also take the hydrojack.

Note The hydrojack is established in a head nest with a small tightness and can be easily taken without use of any tool.

5. Similarly remove other yokes and take hydrojacks.

6. Examine hydrojacks: on cylindrical working surfaces of hydrojacks should not be задиров or scratches. Measure by a micrometer external diameters of hydrojacks (tab. 5.4).

7. Examine nests under hydrojacks in a block head. On their surfaces risks, scratches, teases, excessive unilateral wear are not allowed. Measure diameters of nests under hydrojacks in a head of the block of cylinders, if necessary grind landing nests.

8. Calculate on a difference of the sizes gaps between hydrojacks and nests in a head. For new details gaps should make 0,023–0,060 mm.

9. Grease the new hydrojack and a nest in a head of the block of cylinders with engine oil and establish the hydrojack in a nest.

10. Similarly establish other hydrojacks.

Note After hydrojack replacement at the first start-up the engine can work short time with the increased noise level until while the hydrojack will not be pumped over.