The engines are equipped with hydraulic tappets, which are automatically controlled by the pressure of the lubrication system to compensate for the gap between the camshaft cam and the corresponding valve stem. Therefore, regular checking and adjustment of valve clearances is not required. However, it is essential that a good quality engine oil of the recommended viscosity is used and that the engine oil is changed at the recommended intervals. When starting a cold engine, there is a slight delay until the engine oil pressure equalizes in all parts of the engine, especially in the hydraulic tappets. Therefore, valves can "knock" approximately 10 seconds, after which the knocking disappears. This is the normal state of affairs, provided that all pushers continue to operate silently.
After the engine has not been started for several days, the valves may «knock» for a longer time, as almost all of the oil drains from the top of the motor and bearing surfaces. At this time, care must be taken not to damage the engine, that is, to avoid a sharp change in the engine operating mode until all the pushers are filled with engine oil. When the engine warms up, the fast idle speed (maximum 2000 to 2500 rpm) should not be exceeded for 10-15 minutes, or until valve banging stops. If pusher noise is present, turn off the engine and perform the following steps.
- Disconnect and remove elements of system of injection of fuel.
- Remove the cylinder head cover.
- Rotate the crankshaft until the cam over the tappet to be checked is straight up.
- Press the pusher with a wooden or plastic wedge (see fig. 2.71). If the free travel of the pusher is greater than 0.1 mm, the pushers must be replaced.
Visitor comments