Exam 32: Camshafts and Valve Trains

Technician A says that valve overlap is the number of crankshaft degrees that both valves are closed. Technician B says that valve overlap is the number of degrees that both valves are open. Who is right?

The movement of the camshaft lengthwise in the engine during operation is controlled by ________ between the camshaft drive gear or sprocket and a flange on the camshaft.

Which timing chain type is also called a "silent chain"?

A DOHC V-6 has how many camshafts?

The intake valve opens at 39° BTDC (before top dead center) and closes at 71° ABDC (After bottom dead center). The exhaust valve opens at 78° BBDC (before bottom dead center) and closes at 47° ATDC (after top dead center). Which of these is correct regarding this cam timing?

Valve lifters are designed in which of these ways?

The camshaft makes ________ for every revolution of the crankshaft.

What determines the amount of valve overlap?

Two technicians are discussing variable valve timing. Technician A says that changing the exhaust valve timing helps reduce exhaust emissions. Technician B says that changing the intake valve timing helps increase low-speed torque. Who is right?

Hydraulic valve lifters can make a ticking noise when the engine is running if ________.

On an engine with variable cam timing, the cam timing can be changed by use of ________.

The valves could be bent if the timing belt breaks on which of these?

Technician A says that the pushrods should be rotating while the engine is running if the camshaft and lifters are okay. Technician B says that the camshaft rotates at one-quarter the crankshaft speed. Who is right?

Identify this component.

If the exhaust valve opens at 57° before BDC (before dead center) and closes at 29° after TDC (top dead center), what is the exhaust valve duration in degrees?

Which term is used to describe the number of degrees of crankshaft rotation for which the valve is lifted off the seat?

Flat-bottom valve lifters rotate during operation because of the ________ of the camshaft.

A cylinder deactivation system uses ________ ________ to operate the system.

The PCM controls cam timing by use of ________.

If lift and duration remain constant and the lobe center angle decreases, then ________.