Replacement of hydraulic engine

Lifters engine DOHC, made in the form of cylindrical pushers located between the camshaft and valves combine two functions: the transmission of force from the camshaft to the valves and eliminate gaps in their drive.

The work is based on the principle of hydraulic incompressible engine oil, continually filling with the engine hydraulic lifters inner cavity and moves it to the plunger when a gap in the valve actuator. This ensures constant contact pusher (arm valve drive) with a cam of the camshaft without clearance. This eliminates the need to adjust the valves for maintenance. The operating principle of the lash is shown in Fig. 5.7. The oil pressure necessary for tappet is fed in its internal cavity of the A and B channels in the lubrication system of the engine through a lateral opening in the valve 6 provided in the annular groove of its cylindrical surface. When the valve is closed 1 follower 6 (via a plunger 7) and the sleeve 9 bursting force of the spring 8, respectively, are pressed to the cam 5 camshaft and the valve stem end. The pressure in cavities A and B are the same, the return valve 3 is pressed against the tappet seat 7 by a spring in the plunger 2. In this case, the clearances in the valve mechanism are absent. By rotating the camshaft the cam 5 is incident on the plunger 6, moving it and the associated plunger 7. The plunger 7 move in the sleeve 9 leads to a sharp increase in pressure in cavity B. Despite the small leakage of oil through the gap between the plunger and the barrel, the plunger 6 and the sleeve 9 are moved integrally and open the valve 1. Further rotation of the camshaft cam 5 reduces the pressure on the pusher 6 and the oil pressure in the cavity B becomes lower than that in the cavity A. The check valve 3 opens and allows the oil chamber A is connected to the engine oil line, in the cavity B. The pressure in cavity B increases, the sleeve 9 and the plunger 7, moving relatively to each other, are selected clearance in the valve mechanism.

The pressure oil supplied to the lash, regulated by a special valve in the cylinder head. Because after the engine of the channels extending from the oil pump, the oil flows into the oil pan, and the channels for supplying oil to the lash remain filled after the engine is started in the cavities of the past can form air pockets. To eliminate them in the channels of the oil supply of the engine are provided compensation calibrated hole provides automatic purge cavities lash. Besides compensatory holes allow some to reduce the oil pressure supplied to the hydraulic lifters at high speed of the crankshaft of the engine, when the pressure in the cavity of the lash can become so great that his pusher, leaning on the occipital part of the cam camshaft, slightly open the valve at the moment, is not relevant phase timing.

Almost all the fault of hydraulic diagnosed by the characteristic noise issued by the timing in different modes of operation.

The noise from the valve can sometimes be eliminated by slightly turning the spring or the valve around the longitudinal axis. To do this, follow these steps.

If the valve and the spring are good, and the sound of the valves still be heard when the engine, tappet defective. Replace it as follows.