199005122 - INTRODUCTION - PISTONS AND CONNECTING RODS

CONSTRUCTION SPECIFICATIONS

The connecting rods are made from carbon steel and the gudgeon pins are the "floating" type.The connecting rod comprises a casing or stem, with a rectilinear axis, which rigidly connects the small end, hinged to the piston pin, and the big end, hinged on the crank pin with bearings in between.The small end contains a bush made from an anti-friction material that cannot be replaced on its sown and is handled by the Parts Dept. together with the connecting rod.The big end is divided into two sections for fitting reasons: the fixed part is in one piece with the casing and the moving part is connected to the former by studs.The two sections are divided by fracture lines to guarantee correct matching. This technique combines simple construction with low production costs.Since the connecting rod is subjected to compression and combined compressive and bending stress forces it tends to become distorted; as a result the connecting rod body should be made in such a way as to combine lightness with maximum resistance and is therefore constructed with a double T section.The connecting rod is the main element connecting the piston with the crankshaft.The pistons in silicon aluminium alloy with a graphite coating on the skirt are divided into three size categories with an arrow stamped on the crown to indicate engine rotation direction to ensure correct installation.