Poppet work
When the engine is running, the poppet 203 is unloaded if the cam 184 of the camshaft 185 is at the top. In this case, the spring (d) expands the compensator 204 so that it rests on the bottom of the valve stem 195, and at the top of the pressure finger (A) presses the poppet 203 against the camshaft.
In this position, all holes (e) blocked and engine oil can neither flow in nor out of the working chamber (With). Once the poppet has been loaded by the rotating camshaft lobe, the ball valve (V) the oil in the working chamber will also close, due to its incompressibility, it will work as one solid body. So the distance (L) with each revolution of the camshaft, it will adjust accordingly to the changing dimensions of the mating parts.
An external sign of a hydraulic poppet pusher is a running oil groove and the absence of shims.
Attention! Noises in the valve actuator when starting the engine are normal. When the engine is stopped, depending on the position of the cam, more or less oil is squeezed out of the pusher. This leads to the appearance of noise that does not stop until the hydraulic pusher, with the engine running, is filled with oil again. Depending on the circumstances, this process may continue until the engine has reached operating temperature.
Attention! To ensure the perfect operation of the hydraulic tappets, an oil leakage block is located in the cylinder head, which prevents the complete leakage of oil from the cylinder head when the engine is stopped.
Examination
Hydraulic tappets must be checked if the noise in the valve drive does not disappear when the engine reaches operating temperature.
1. Warm up the engine while driving, leave to idle until the radiator fan turns on.
2. Within 2 minutes, raise the engine speed to 2500 rpm.
3. If the hydraulic tappets continue to make loud noises, stop the engine and remove the cylinder head cover. Rotate the camshaft until the cams of the cylinder to be checked point upwards. To do this, set the gearbox to neutral, apply the handbrake and turn the crankshaft by the belt pulley bolt with a suitable wrench clockwise.
Attention! Do not rotate by the camshaft drive gear bolt, as this will overload the toothed belt. The crankshaft and camshafts can also be rotated as follows: engage 5th gear and push the car forward or backward.
4. Press the poppet down with a wooden or plastic wedge. If a play of more than 0.1 mm is felt, replace the poppet.
Attention! After installing a new hydraulic pusher, the engine must not be started for about 30 minutes, otherwise the valve will collide with the piston, which can lead to their failure.
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