Chapter 09: Introduction

After studying this chapter, you should be able to:

LO 9-1 Identify the purpose and list the names of components associated with the cylinder head and valve train.

LO 9-2 Describe the functions, construction, composition, types, and applications of diesel engine cylinder head assemblies.

LO 9-3 Describe the features and explain the advantages of overhead camshaft engines.

LO 9-4 Identify and describe the characteristics of timing in a diesel engine.

LO 9-5 Identify and describe the purpose, construction, and operation of components used in the valve train.

LO 9-6 Identify and explain the purpose, construction, and operation of the camshaft.

LO 9-7 Identify and describe the purpose, types, construction, and operation of the engine geartrain.

LO 9-8 Outline maintenance procedures and practices used to service diesel engine cylinder heads.

LO 9-9 Identify and describe the purpose, construction, and applications of cylinder head gaskets.

LO 9-10 Outline the service procedure used to adjust the clearances of intake and exhaust valves.

Many of the trucks and buses in the fleet operation where you work are encountering premature head gasket failures. Some of the head gasket failures are causing engines to leak externally while others are pressurizing the cooling system or leaking coolant into the crankcase. After some investigation, you discover that many of the engines having the failures were overhauled and rebuilt prior to your arrival at the fleet repair shop. You realize that most of these engines will need to be repaired once again. As you consider how you will precede with the replacement of the cylinder head gaskets, consider the following:

1. Outline some diagnostic procedures you could follow to identify the engines that need immediate attention and head gasket replacement.
2. Outline the inspection procedures you should undertake to determine whether the cylinder heads and valve train gears are in serviceable condition or require replacement.
3. Outline the procedures that should be followed when replacing the head gaskets.