Page 57 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

LESSON 11 - 14: Importance of servicing cylinder Head-

Precautions to be observed while
servicing cylinder head

Objectives

At the end of this lesson you shall be able to
• explain importance of servicing cylinder head.
• precautions to be observed while servicing cylinder head

Importance of servicing cylinder head
• Servicing is important for cylinder safety, performance and long fuel mileage.

• Maintenance helps identify and fix problems such as leaks or wear, ensuring the cylinder is safe and functional.
• In addition, servicing can optimize performance, reduce the risk of wear and extend cylinder life. Damaged
cylinder heads result in reduced cylinder pressure due to oil and water mixing.

• Better Compression: Servicing the cylinder head includes inspecting and protecting the valves, valve seats
and valve guides for any problems. Ensures proper sealing and compression. Which is essential for the power
and efficiency of the engine.
• Leak Prevention: Cylinder head gaskets wear out over time, which can cause coolant-oil leaks. Servicing the
cylinder head includes inspecting and replacing the gasket as necessary, to prevent leaks that could cause
engine overheating.
• Enhanced Cooling: The cylinder head plays an important role in dissipating heat from the combustion process.
Cleaning and checking the coolant passages is important in cylinder head servicing to ensure efficient cooling,
prevent overheating and engine damage.
• Extended Engine Life: By replacing problems such as worn valve elements, surfaces, or worn gaskets,
servicing the cylinder head can increase engine performance over a longer period of time. Proper maintenance
helps prevent costly repairs and premature engine failure.
• Optimum Fuel Efficiency: A proper cylinder head ensures optimum combustion chamber position and valve
timing, thereby improving fuel efficiency and reducing emissions.
• Smooth Engine Operation: Cylinder head servicing resolves problems like valve noise, or misfire, resulting
in smooth engine operation and an overall better driving experience
Precautions to be observe while servicing cylinder head
Cylinder Head: The cylinder head (Fig 1-13) is bolted to the machined surface on the top of the cylinder block.
Its function is to enclose the top of the cylinders. Both the top of the cylinder block and the bottom of the cylinder
head must be machined smooth to allow for an air-tight seal. The cylinder head fits directly over the cylinders
and forms the combustion chamber of each cylinder. In these chambers, the engine burns air and fuel to produce
mechanical energy.
You can also see that several small holes are cut into the bottom of the cylinder head When the cylinder head is
bolted onto the cylinder block, the holes are aligned which allows oil and water to pass from the cylinder block into
the cylinder head. The oil is then circulated back through the block while the water leaves the engine through the
large holes on the front of the cylinder head.
Fig 1-14 shows the cylinder head in position to be installed on the cylinder block. A head gasket placed between
the cylinder head and cylinder block ensures an airtight seal. Now that you have enclosed the cylinders and
formed the combustion chambers, you must have a way to allow the air or air-fuel mixture to enter and exhaust
(burned gases) to exit while keeping the combustion chamber closed as the air-fuel mixture burns. All this is done
with the intake and exhaust valves.

44