Page 127 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

2
Engine systems 111

Wet liner Dry liner
1 2
1

4

2
3

3
1 Liner 1 Liner
2 Sealing ring 2 Coolant
3 Coolant 3 Cylinder block
4 Cylinder block

Figure 2.53 Wet and dry liners

Figure 2.54 Modern engine block

Most modern engines ( Fig. 2.54 ) have specifi c treatments applied to the cylinder
bores and, as such, cannot be rebored or honed. Replaceable liners mean that
the liner and piston assembly can be replaced without the need for specialist
reboring equipment. Commercial vehicle engines often use replaceable liners to
reduce repair times.
Cast iron has been used for cylinder block construction in the past as the
cylinders can be bored directly into the material; in addition, these bores can
be remanufactured or repaired by reboring oversize. Cast iron is porous and
hence the cylinder bore is capable of retaining lubricating oil for lubrication of
Key fact
the contact surfaces. The disadvantage of cast iron is weight. Modern engines
use aluminium and can achieve the same strength and stiffness as cast iron via Aluminium alloy cannot provide a
suitably durable surface for piston
advanced design techniques.
ring contact, so liners made from
Aluminium alloy cannot provide a suitably durable surface for piston ring contact. cast iron or steel are used.
Therefore, cylinder liners or sleeves, made from cast iron or steel, are normally
fi tted into an aluminium cylinder block ( Fig. 2.55 ).