Page 139 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

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Figure 2.80 Details of the bearing: 1, locating lug; 2, oil groove; 3, steel support shell;
4, support coating; 5, nickel coating; 6, surface coating; 7, oil bore; 8, thrust fl ange

Figure 2.81 Dual-mass fl ywheel

2.1.3.4 Cylinder heads

The cylinder head gasket has to form a gas-tight seal at the interface between the
Key fact
cylinder head and the cylinder bores. In addition, it must seal and separate the
cooling water supply jacket and the oil supply and return drillings. Traditional head Modern head gaskets are made
gaskets were constructed from copper and asbestos. Modern material technologies from composite materials.
allow head gaskets to be made from composite materials which have superior
sealing and heat transfer performance ( Fig. 2.82 ).
Head gaskets must always be replaced when the cylinder head is removed
and refi tted. In addition, when refi tting a cylinder head, it is important that the
manufacturer’s information is sought and applied with respect to replacement of
cylinder head bolts where necessary. Correct torque and a tightening sequence
of cylinder head bolts must be followed ( Fig. 2.83 ).
Cylinder heads are cast from aluminium alloy or iron. Aluminium alloy is lighter
but cast iron or steel valve seats and guides must be installed in the head ( Fig.
2.84 ). Cast iron heads generally have valve seats and guides formed directly in
the head material.