Set of big end bearings (2 drillings) Fiat 500/126/126 BIS/Cinquecento

Set of big end bearings (2 drillings):

Exploded-view drawing with accessories

This product fits the following models:

• Fiat 500
• Fiat 126
• Fiat 126 BIS
• Fiat Cinquecento

The Connecting Rod Bearing

The connecting rod — connecting rod bearing; two variations of the same component, which serves as the link between the piston and the crankshaft in an engine. In general language usage, when referring to connecting rod bearings, it usually denotes the shells made of steel-lead bronze or steel-aluminum in the connecting rod foot, connecting the connecting rod to the crankshaft.

The connecting rod bearings are located at both ends of the connecting rod in the connecting rod eyes. The two ends are differentiated into the connecting rod head and connecting rod foot. The connecting rod foot is the larger connecting rod eye, which is usually divided into two parts and attached to the crankshaft. The smaller connecting rod eye at the connecting rod head is typically a single piece; the piston is connected to the connecting rod at this point with the help of a pin. The connection points of the connecting rod with the crankshaft and piston are constantly in motion, which is why these connections cannot be rigidly designed. Therefore, bearings are used: the connecting rod bearings.

In modern internal combustion engines, sliding bearings are typically used at the connection points of crankshaft - connecting rod - piston. In the past, rolling bearings and/or needle bearings were also used.

Connecting rod bearings are not traditional wear parts and are designed to last the entire life of a vehicle. Damage to connecting rod bearings is almost always a result of oil deficiency.
With the engine running and an intact oil circulation, the connecting rod bearings are supplied with oil through oil bores in the crankshaft. The connecting rod bearings are so precisely designed that, in the heated state during operation, minimal gaps form due to material expansion, allowing oil to escape. In the connecting rod foot, oil is carried along by the friction of the movement, creating an oil cushion between the bearing shell and the crankshaft. This thin lubricating film prevents metal-to-metal friction, which would cause significant wear. Through pure fluid friction, only the oil "wears out"—as long as it is present in sufficient quantity and quality.
At the connecting rod head in the piston pin bearing, due to different movement processes, fluid friction is not possible, and accordingly, the bearings are constructed differently.