Page 135 - 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 119

Force transfer from piston crown Force transfer from crankshaft
to crankshaft through the to piston crown through the
connecting rod connecting rod

Figure 2.71 Force transfer

Figure 2.72 Big end bearing: 1, front of engine; 2, identifi cation marks; 3, big end cap; 4, oil
spray hole for cylinder wall lubrication

manufactured from carbon steel in a process known as drop forging to form the
required shape and profi le.
The connecting rod is designed specifi cally with a high resistance to bending,
compressive and tensile forces via an I-section profi le. The piston end, known
as the little end, has an appropriate bush, bearing or clamping arrangement for
the piston pin. The crankshaft end of the connecting rod is known as the big end
( Fig. 2.72 ). This consists of a split bearing with a removable bearing cap. The
bearing cap is attached to the connecting rod via bolts or nuts.
It is important to note that the connecting rod and bearing cap are machined
as one unit, and hence, the parts are matched. Therefore, they must always be
reassembled as a pair and fi tted correctly oriented.