Contents: Checking chain wear ↡ Chain tensioner ↡
Fig. 4.20. Operation diagram of the drive chain with one camshaft: 1 – camshaft gear; 2 – chain tensioner; 3 – fuel injection pump drive gear; 4 – chain tensioner; 5 – oil pump chain tensioner; 6 – oil pump drive gear; 7 – crankshaft gear; 8 – timing chain tensioner shoe; 9 – hydraulic tensioner
The camshafts are driven from the crankshaft by means of a double-row chain (the so-called duplex chain). The camshaft gear has twice as many teeth as the crankshaft gear. Therefore, the camshaft rotation speed is half that of the crankshaft (Fig. 4.20). On the non-adjustable (tensioned) side, the chain is limited by a special plate (chain tensioner), on the other hand it is pressed by the tensioner shoe.
Checking chain wear
Fig. 4.21. Checking chain wear
[Article text obtained from the website: MercedesMAN.ru]
If noise occurs, the condition of the chain should be checked (Fig. 4.21). When worn, the chain lengthens. This lengthening causes wear of the camshaft gear. In the worst case, the gear teeth may break and the chain will slip, causing serious damage to the engine.
If the chain is checked in a timely manner and its wear is detected, it is enough to replace the chain and the camshaft gear. In case of severe wear, it is necessary to replace all parts of the chain drive. This work is performed at the service station by specialists.
Chain tensioner
Located on the right side of the cylinder head. The tensioner presses the chain through the shoe. Its force is made up of the force of the built-in spring and the pressure of the oil passing through the tensioner. The oil in the tensioner also smooths out the loads when the chain is suddenly tightened.
A faulty tensioner must be replaced. Lubricate the new tensioner with engine oil beforehand.