Connecting Rod Supplier & Manufacturer

Chinese FEDA is a leading supplier and manufacturer of high-quality connecting rods. We leverage advanced technology and superior manufacturing methods to provide durable, performance-optimized connecting rods for a diverse range of applications. Our expertise in the industry, coupled with our commitment to customer satisfaction, ensures that we consistently deliver products that meet the highest standards of excellence. Trust Chinese FEDA for your connecting rod requirements, and experience the difference of quality and reliability.

Everything About Connecting Rod

Table of Contents

What is a Connecting Rod?

The connecting rod, or con rod, is a fundamental component in an internal combustion engine. The con rod links the piston to the crankshaft, converting the piston’s reciprocating motion into the crankshaft’s rotational motion. This conversion is crucial for the engine’s operation.

In larger engines, the con rod connects the crosshead to the crankshaft, translating the linear motion of the crosshead into rotational motion. This makes the con rod a key element in transforming energy within the engine system. Made from durable materials, the con rod is designed to withstand high-frequency stress and intense forces.

What is a Connecting Rod

Connecting Rod Stresses

Connecting Rod Stresses

Connecting Rod Stresses

A connecting rod (con rod) in an engine endures significant stresses, including compressive stress during the power stroke, tensile stress during the exhaust and intake strokes, and bending stresses due to crankshaft rotation.

Forces in a Connecting Rod

The forces acting on a con rod involve gas pressure on the piston, inertial force from the piston and con rod’s mass, and centrifugal forces from crankshaft rotation. Balancing these forces is crucial for engine efficiency and con rod longevity.

Parts of a Connecting Rod

The connecting rod, while a singular entity within the engine system, can be further dissected into its constituent sub-components. Each of these sub-components plays a distinctive role within the overall functionality of the connecting rod, contributing to the efficient operation of the engine as a whole.

1、Big end

2、Small end



5、Bearing insert

6、Bolt and nut

Parts of a Connecting Rod

Connecting Rod Big End

connecting Rod Big End

The “Connecting Rod Big End” signifies one of the integral sub-components of the connecting rod. This component forms the junction between the connecting rod and the crankshaft, specifically linking to the crank pin on the crankshaft. Its assembly involves the use of specially designed nuts and bolts to guarantee a robust and secure linkage, a critical element for the efficient translation of motion within the internal combustion engine.

Small End Configuration

The “small end” of the connecting rod serves as a critical interface within the engine. In the context of long-stroke reciprocating engines, this segment forms the connection to the crosshead, a component that transfers the piston’s linear motion to the connecting rod. Alternatively, in trunk piston engines—commonly found in smaller machinery such as generators—the small end directly engages with the piston via the gudgeon pin, also referred to as the piston pin or wrist pin.

This distinction in connecting rod design is primarily driven by engine scale and application. Large marine engines, for instance, necessitate the inclusion of a crosshead due to their substantial size and power requirements.

Rod Design And Functionality

The core section of the connecting rod, simply referred to as the “rod,” constitutes the physical link between the small end and the big end. Its design can adopt the form of either an I-beam or an H-beam, each offering specific structural advantages.

An I-beam rod configuration provides an optimal balance between load-bearing capacity and material efficiency, reducing deflections under load for a given quantity of material.

In addition, the rod often incorporates central lubrication passages. These channels facilitate the flow of lubricating oil from one end of the rod to the other—an essential feature in engines equipped with oil-cooled pistons.

The alternative H-beam design is typically utilized in high-performance applications. This design offers increased rigidity and is better suited to manage high compressive forces. However, due to the complexity involved in their manufacturing process, H-beam rods often carry a higher price tag compared to their I-beam counterparts.


Bush and Bearing Inserts

Bush and Bearing Inserts

The “bush” is a bearing located on the connecting rod’s small end, facilitating smooth motion between the piston and the rod. Given its consistent metal-to-metal contact with the piston pin and high load, it must be designed for substantial cyclic loading.

“Bearing inserts” at the rod’s big end create a low-friction buffer with the crankshaft. By preventing metal-to-metal contact and maintaining an oil film, these inserts enhance crankshaft and con rod longevity.

Fastening Components and Material Selection

Bolts and nuts secure the connecting rod at both ends, enduring various stresses, making them the most stressed fasteners in the engine. Regular maintenance can reduce failure risk.

Material selection for connecting rods is critical, considering strength and fatigue resistance. Steel is commonly used in automotive applications, while aluminum alloy or nodular steel are suitable for high compressive forces, and cast or forged steel for high tensile forces. Cast iron offers a cost-effective solution for lower performance needs, while titanium is a premium choice for high performance with weight reduction. Other materials include sintered metal, micro-alloyed steel, and spheroidized graphite cast iron.

Types of Connecting Rods: Manufacturing Methods

Connecting rods can be categorized into four types, based on their manufacturing method:

1. Cast Rod

The casting process forms cast rods, suitable for low-power, low-speed applications due to their affordable production costs. However, their use in high-performance scenarios is not recommended.

2. Forged Rod

Forged rods, created via the forging process, offer improved mechanical properties such as ductility and fatigue strength, due to aligned grain structure. These robust rods can endure higher compression ratios while maintaining size and weight standards.

3. Powdered Metal Rod

Powdered metal rods, the go-to choice in the automotive industry, offer an economical yet high-performance alternative to traditional rods. Their production involves pressure molding metal powder and furnace heating. They might also undergo forging for enhanced mechanical properties.

4. Billet Rod

Billet rods, cut from a single steel billet using CNC methods, offer design flexibility. However, their unchanged grain structure can impact strength, and their customization leads to higher costs and production time.

Conclusion: The Importance of the Connecting Rod

Failure of the connecting rod, a crucial engine component, can lead to engine breakdown and potential safety hazards. Regular condition monitoring, proper design, and maintenance can prevent such failures, reinforcing the engine’s overall functionality and longevity.