Exam 9: Camshafts, Lifters, Timing Belts, and Chains

Pressures on a lifter can reach 100,000 psi.

Technician A says valve overlap occurs at the bottom of the intake stroke. Technician B says valve overlap occurs at the top of the intake stroke. Who is correct?

The camshaft term for the number of degrees of crankshaft travel that the valve is off its seat is called _____.

Lifters are being discussed. Technician A says there is only 0.0002" of clearance between the plunger and lifter body. Technician B says dirt particles in an engine are generally larger than 0.0002". Who is right?

As the oil pump in a pushrod engine is turned, resistance to pumping the oil causes the cam to be forced toward the rear of the engine. What is this motion called?

When a cam lobe wears out, which will it most likely be?

What is an interference engine?

Technician A says that it is necessary to keep flat tappets in order if the old cam and lifters are to be used again. Technician B says that used roller tappets should not be installed on a new camshaft. Who is right?

Technician A says a new or rebuilt engine should have the idle maintained above 1500 rpm for at least 20 minutes to insure proper lubrication and break in. Technician B says long periods of idle are hard on the camshaft. Who is correct?

Technician ​A says that camshaft end thrust on a pushrod engine with a camshaft-driven oil pump results from resistance of oil being pumped by the oil pump. Technician B says that flat tappet camshafts are usually inspected by visually checking the wear pattern on the lobes for edge loading. Who is right?

When there is no clearance between the valve stem and its actuator, this is known as _____.

In reference to fuel use, what is CAFE?

What is the term for the period when the intake and exhaust valves are both open?

Timing belt sprockets should be cleaned with a petroleum-based solvent.

When there is too much valve lash on a mechanically adjusted valvetrain, the lifter or cam follower can miss the _____ ramp.

Technician A says camshaft end thrust on some engines is controlled by the distributor. Technician B says timing can change if camshaft end thrust is not controlled. Who is right?

What part is replaced along with a timing belt when an engine does not have a tensioner bearing?

The _____ circle is what the cam would be if there were no lobe.

Another term for mechanical lifter is tappet.

What name describes an engine that can have a collision between the piston and valve when the timing chain or belt breaks?