Nominal and maximum speed (Renault 19)

An internal combustion engine produces its greatest power at a certain speed; this is called the nominal speed. Increasing the engine speed above the nominal speed does not increase the power. The maximum permissible speed depends on the engine type: from 4500 rpm (diesel) to 6500 rpm (16-valve engine). In this case, we are talking about the "working speed", which is not dangerous during long-term operation of the engine in this mode. Increasing the number of revolutions above the specified values has an adverse effect on the condition of the engine. The engine then begins to make a lot of noise; this occurs due to crankshaft vibrations in the bearing area and valve vibrations. On a 16-valve engine, the operation of hydraulic compensators is disrupted.

If the vibrations are too strong, the valve springs or valve levers may break; in addition, the push rod may be damaged (C-engine) and the valve tappet, which will cause the valve to break. The latter is the worst option, as the valve can get caught under the moving piston, which will cause the engine to break. With a broken valve lever, valve tappet or broken tappet rod (C-engine) only the corresponding valve and cylinder do not work. This will be noticeable by the decrease in engine power. In order to know the permissible engine speed, some Renault 19 modifications are equipped with a tachometer at the factory. This device has some lead - at the top of the scale up to 5%. Thus, 6000 rpm on the tachometer actually corresponds to only 5700 rpm.

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