Vehicles with a 150 hp petrol engine.
The 16-valve engine is equipped with hydraulic poppet lifters, which does not require valve clearance adjustment as part of vehicle maintenance. In addition, this achieves a reduction in valve drive noise.
With the engine running, the load from the pusher 203 (see illustration 8.0) is removed by turning the cam 184 of the camshaft 185 up.
8.0 Function of the poppets
In this case, the spring d presses on the compensator 204, the lower part of which is pressed against the valve stem 195, and from above the pressure pin a presses the poppet pusher 203 to the camshaft. At this point, engine oil flows out or flows into the working chamber c through holes e. As soon as the cam of the rotating camshaft begins to press on the poppet again, the ball valve b closes and the remaining oil creates a dynamic pressure, because it does not have the ability to compress as a solid body. The distance L is thus kept constant with each rotation of the camshaft, corresponding to the dimensions of the valve drive parts.
A distinctive external feature of hydraulic poppet pushers is the presence of a circular groove and the absence of adjusting washers. Repair of hydraulic pushers is not possible.
Attention! Valve actuation noises when starting the engine are normal, because when the engine is stopped, depending on the position of the cam, some oil flows out of the corresponding tappet. As a result, the tappets at start-up begin to work with a knock due to lack of oil. These noises disappear as the pushers are filled with oil. Sometimes this phenomenon can continue until the engine warms up to operating temperature. To ensure the perfect operation of the bucket tappets, there is a shut-off valve in the cylinder head that prevents the outflow of oil from the oil channels when the vehicle is parked with the engine turned off.