Question 1

What are automotive connecting rods or conrods?

Accepted Answer

Automotive connecting rods or conrods are critical components in an engine's internal combustion system. They are usually made of high-strength steel or aluminium alloy and are designed to connect the piston to the crankshaft. Aftermarket conrods are often used to upgrade engine performance capability or to replace damaged or worn-out factory rods.

Question 2

How do I know what size engine rod to get?

Accepted Answer

Conrods are specific to each engine as there are a large number of variables in the design. These include conrod length big end journal diameter and width, gudgeon pin end diameter and width. Having selected the correct conrod for your engine, there may also be a choice between different designs. These designs relate to the shape of the main shaft  or beam of the conrod and are often described as being H beam or I beam. I beam design conrods are generally considered to be stronger and lighter than the H beam equivalent.

Question 3

How do Crankshaft Rods or connecting rods work?

Accepted Answer

Crankshaft rods or connecting rods work by transferring the up-and-down motion of the piston to the rotational motion of the crankshaft. When the piston moves up, the connecting rod is pulled up, and when the piston moves down, the connecting rod is pushed down, which rotates the crankshaft. The shape and design of the conrod play a crucial role in the engine's overall performance capability and reliability.

Question 4

What causes conrod failure in an engine?

Accepted Answer

Conrod failure in an engine can be caused by several factors, including inadequate lubrication, excessive bearing wear, incorrect assembly or torque specifications, high RPM operation, and engine detonation. Aftermarket connecting rods can be more resilient and durable than factory rods, but it is still important to use high-quality components, follow proper assembly procedures and have a good tune to avoid conrod failure.

BMW 4JJ1 RB25 NEO Conrods