Cylinder head and camshaft
The cylinder head is, to a certain extent, the engine cover. It has valves, and it also has channels for the working mixture and exhaust gases. The head is cast from an aluminum alloy and inside, like the cylinder block, is cooled by a circulating coolant.
At the very top of the cylinder head are the camshafts. With the help of cams, the valves open and close at certain positions of the piston in the engine cylinder.
An intermediate element between the camshaft and valves are rocker arms or pushers. Each pushrod or rocker sits above a valve and two valve springs. The cams do not touch the pushers exactly in the middle, but slightly offset, as a result of which the valves turn slightly around their axis with each push down. This achieves tightness of the valve in the seat of the cylinder head.
Elements of the cylinder head of 1.6- and 1.8-liter engines
1 - casing;
2 - hose;
3 - semicircular seal;
4 — a cover of a head of the block of cylinders;
5 - gasket;
6 - camshaft rotation angle sensor;
7 - intake camshaft;
8 - exhaust camshaft;
9 - stuffing box;
10 — a cover of the forward bearing of a cam-shaft;
11 - camshaft gear;
12 - cylinder head;
13 - housing of the channel of the lubrication system.
Elements of the cylinder head 2.0 l engine
1 - cylinder head;
2 - gear wheel;
3 - exhaust camshaft;
4 - intake camshaft;
5 - asterisk;
6 - elements of the intake valve;
7 - elements of the exhaust valve;
8 - chain;
9 - crankshaft angle sensor.
Hydraulic pusher
In the presence of hydraulic adjustment of valve clearances, there is no need to control these clearances, but it is necessary that the closed valves fit snugly against the valve seats, and at the same time the necessary tightness would be ensured.
Attention: Knocks, which occur when bearings are damaged, can be emitted by an engine with hydraulic pushers when first started after a long period of inactivity. This effect occurs if oil flows out of the hydraulic tappets and this creates a backlash in the valve drive. However, there is no cause for concern: the noise disappears after a while and the valve drive runs silently again. If the hydraulic pusher knocks for a long time or even when the engine is warm, it must be checked.