Exam 12: Upper-End Theory and Service

Technician A says heat is transferred from an exhaust valve to the cylinder head through the valve seat. Technician B says some exhaust valves have a hollow stem filled with silicone to transfer heat to the valve guide. Who is correct?

How does refinishing a valve face and the valve seat affect its position in the cylinder head?

Valve springs should be checked for all of the following EXCEPT:

Describe a phaser.

Why does a properly finished valve seat have three different angles?

What is the function of a rocker arm?

Describe a hemispherical combustion chamber.

Valve guides are _____.

Installed spring height [the distance between the spring seat and the bottom of the retainer] can be measured with a spring height gauge or ____________________.

A cylinder head may be made of cast iron or aluminum.

A pentroof combustion chamber is normally found on a(n)_____type cylinder head.

A cylinder head that has the intake manifold and all the intake valves on one side and the exhaust manifold and exhaust valves on the opposite side is called a ____________________type cylinder head.

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.

What procedures should be followed after refinishing a valve face?

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

The surface of a valve that comes into contact with the valve seat is called the valve ____________________.

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.

Valve stem wear may be measured with a ____________________.

Hemispherical combustion chambers are being discussed. Technician A says the flame path from the spark plug to the piston head is long, which provides efficient burning. Technician B says the cross-flow arrangement of the inlet and exhaust valves allows for a free flow of gases in and out of the chamber. Who is correct?

Technician A says worn valve stem seals can increase oil consumption. Technician B says worn valve stem seals can cause valve deposits. Who is correct?