Exam 12: Upper End Theory and Service

Aluminum cylinder head bolts should never be loosened or tightened when the metal is hot.

Prussian blue or machinist dye is used to ______.

What is the function of a rocker arm?

What procedures should be followed after refinishing a valve face?

After resurfacing a valve seat at 45 degrees, the seat is too wide and the contact pattern extends all the way up to the valve margin. What should be done to bring the seat width into specifications?

The camshafts and timing gears are removed from the cylinder head. A technician covers the return oil holes in a camshaft with electrical tape and applies compressed air to the other oil hole. With the camshaft held stationary, the timing gear rotates a few degrees counterclockwise. When the air pressure is released, the timing gear rotates clockwise back to its original position. This proves that the ____________________ is working properly.

The performance of an engine, its fuel efficiency, and its exhaust emissions all depend to a large extent on the shape of the combustion chamber.

A typical interference angle is _____ degree(s).

Which type of surfacing machine uses underside rotary cutters?

Technician A says multivalve engines have a more complete combustion than conventional engine designs. Technician B says the benefits of multivalve engines are offset to some extent because a more complicated camshaft arrangement is needed. Who is correct?

____________________ is a very rapid movement of gases that causes the air and fuel to mix better and improve combustion.

While disassembling a cylinder head, what would indicate that the valve seals are worn or damaged?

Induction-hardened integral valve seats are found on _____ cylinder heads.

What is the most common cause of warpage in an aluminum cylinder head?

Aluminum cylinder heads weigh roughly half as much as cast-iron heads.

Many camshaft journals run directly on aluminum supports and do not use bearing inserts.

Describe a phaser.

Multiple valve engines tend to be more efficient than engines with two valves per cylinder because:

Technician A says the valve seats must be ground before the valve guides are serviced. Technician B says before grinding the valve seats, they should be checked for cracks. Who is correct?

The type of valve used in automotive engines is called a ____________________.