Diesel Engine Valve Mechanism


1. Four-valve mechanism

The valve mechanism of the diesel engine is basically the same as the one on the gasoline engine. However, some valve mechanisms are distinctive to the engine. The four-valve mechanism consists of the valve rocker arm and valve bridge. When the rocker arm is pushed up by the camshaft, the valve bridge slides along the guide pin and pushes down the two valves simultaneously to open them. In this way, a single camshaft is able to operate four valves per cylinder. Through the use of four valves, not only is the intake and exhaust effectiveness improved, but also the injection nozzle can be placed in the center of the combustion chamber.


Valve clearance is adjusted using two adjusting screws, (1) and (2).

2. Replacement interval of timing belt

The timing belt of the diesel engine must be replaced every 100,00km (60,00miles) or 150,00km (90,00miles), depending on the engine models. In some diesel engine vehicles, a timing belt replacement warning light is provided. This light will come on at the specified timing belt replacement intervals. The timing belt warning light must be reset after replacing the timing belt. The method for resetting varies by the model.

Example 1:

Remove the grommet under the speedometer and push the warning light reset knob with a thin rod.

Example 2:

Remove the cancel switch screw and reinstall it in the other installation hole.

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