Using the compressed air/water method, you will actually be able to see bubbles forming past a bent valve on the intake or exhaust side—the larger the leak, the bigger the bubbles.

If the valves don't open the intake and exhaust at the right time, it will restrict airflow into the engine, which may manifest as rough idling. Oil consumption. You may notice the level going down on ...

The intake ports have also been raised to make room for the direct injection system. After combustion occurs, the exhaust exits through 1.59-inch (40.4mm) hollow sodium exhaust valves.

At the engine’s 725-rpm idle, the intake, compression, power, and exhaust strokes, together, happen in just 0.2 second, literally the blink of an eye.

Stefan Gundmalm, Andreas Cronhjort, Hans-Erik Angstrom, Divided Exhaust Period, SAE International Journal of Engines, Vol. 6, No. 2 (June 2013), pp. 739-750 ...

The effects of individual valve timing events on the exhaust emissions of a single-cylinder engine were determined at partload, low-speed, test conditions. The time of opening and closing of the ...