So, connecting rods, form the link, between the crankshaft and the pistons.

Consequently, transferring the inertial forces, to the crankpins on the crankshaft.

So, the rod pushes and pulls the piston, into and out of the cylinder. And, the small eye, on the piston side of the rod, serves as a mounting for the piston pin.

Finally, connecting rods are then mounted with rod bearing shells on the crankshaft rod journals.

Once the rod turns, it allows the piston to move up and down. This is how rotational torque, gets created in the engine.

Small End

The small rod eye and the conrod bush.


The connecting rods shank connects the small end of the rod, to the big end of the rod. The rod shank normally has a double T cross section.

Big end

The big end, is the lower part of the rod.

Firstly, they are given break lines or laser notches and split into two parts. With the point of fracture, ensuring that the connecting rods, fit together precisely. They offer more advantages in terms of strength, cost and production accuracy.
Once assembled, the joint faces are barely visible. They fit together very precisely, thus allowing maximum force transmission.

All rods for automotive use, need to be lightweight. But, strong enough to withstand and transmit, the thrust from the pistons to an engine’s crankshaft. Finally, connecting rods are available in, a variety of sizes and materials ideal for certain situations.

Common causes of connecting rod failure are, tensile failure from high engine speeds. Also, the impact force when the piston hits a valve (due to a valve train problem); rod bearing failure (usually due to a lubrication problem, or incorrect installation of the rod.


So, most late model stock engines, use powder metal connecting rods. Because, they are inexpensive to manufacture; require minimal machining to finish and are adequate for, stock power levels and normal driving.

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