Page 125 - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

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Engine systems 109

Figure 2.49 V8 crank

Figure 2.50 Typical fi ring orders – V8 engine

2.1.3 Engine components

This section explores various different engine designs and components found on
modern road vehicles ( Fig. 2.51 ).

2.1.3.1 Engine block and liners
Engine cylinders, when cast in a single housing, are known as the engine block.
Usually, the engine block is manufactured from cast iron ( Fig. 2.52 ) or aluminium
alloy. In the latter case, cast iron or steel liners form the cylinder bore. The engine
block forms the major component of a ‘short’ motor.
The cylinder bores are formed via a machining process with a boring tool to give
the correct form to the cylinder within closely specifi ed tolerances. Cast iron is a
mixture of iron with a small amount of carbon (2.5–4.5% of the total). The carbon
added to the iron gives a crystalline structure that is very strong in compression.
In addition, it is slightly porous and this helps to retain a fi lm of lubricating oil on