3934086
Rocker Lever Adjusting Screw
Cummins®

The 3934086 Rocker Lever Adjusting Screw, manufactured by Cummins, is a component designed for use in heavy-duty truck engines. Cummins, a well-established name in the automotive and heavy-duty truck industry, produces a range of high-quality engine parts, including the 3934086. This screw plays a role in the valve train mechanism, contributing to the efficient operation of the engine ¹.

Basic Concepts and Functionality

Rocker lever adjusting screws are integral to the valve train mechanisms in engines. They facilitate the precise adjustment of valve clearances, which is vital for the proper functioning of the engine. The rocker lever adjusting screw operates by allowing fine-tuned adjustments to the rocker arm, ensuring that the valves open and close at the correct intervals. This precise control over valve operation contributes to the overall efficiency and performance of the engine ².

Purpose and Role in Truck Operation

The 3934086 Rocker Lever Adjusting Screw serves a specific purpose in the operation of heavy-duty trucks. It aids in maintaining the proper valve clearance, which is crucial for the engine’s performance. By ensuring that the valves open and close at the correct times, this screw helps to optimize the engine’s combustion process, leading to improved fuel efficiency and power output. Additionally, it contributes to the longevity of the engine by reducing wear and tear on the valve train components ³.

Key Features

The 3934086 is designed with several key features that enhance its functionality and durability. It is constructed from high-quality materials that can withstand the demanding conditions of heavy-duty truck engines. The screw’s design allows for easy adjustment, ensuring that mechanics can fine-tune the valve clearances with precision. Additionally, its robust construction ensures that it can endure the high temperatures and pressures present in the engine compartment.

Benefits

Using the 3934086 offers several benefits. It contributes to improved engine efficiency by ensuring that the valves operate at optimal clearances. This results in better fuel economy and enhanced power output. Additionally, the screw’s design reduces maintenance requirements, as its precise adjustment capabilities minimize the need for frequent re-adjustments. Furthermore, its durable construction enhances the reliability of the engine, even under demanding operating conditions.

Installation and Adjustment Procedures

Proper installation and adjustment of the 3934086 are vital for ensuring optimal engine performance. The installation process involves securing the screw in place and making the necessary adjustments to achieve the correct valve clearance. Torque specifications should be followed to ensure that the screw is tightened to the appropriate level. Recommended practices include using the correct tools and following a systematic approach to adjustments, ensuring that all valves are set to the manufacturer’s specifications.

Troubleshooting and Maintenance

Common issues associated with rocker lever adjusting screws include improper valve clearance, which can lead to engine performance issues. Troubleshooting tips for diagnosing and resolving problems involve checking the screw’s adjustment and ensuring that it is securely in place. Regular maintenance, such as periodic checks of the valve clearances and the condition of the screw, can help prolong its lifespan and ensure continued engine performance.

Cummins: Manufacturer Overview

Cummins Inc. is a leading manufacturer in the automotive and heavy-duty truck industry, known for its commitment to quality, innovation, and customer satisfaction. The company has a diverse product portfolio that includes engines, filtration systems, and other engine components. Cummins’ reputation is built on its dedication to producing reliable and high-performance parts, making it a trusted name in the industry.

Compatibility with Cummins Engines

The 3934086 is a critical component in the operation of various Cummins engines. This part is essential for maintaining the proper clearance between the rocker arms and the camshaft, ensuring optimal engine performance and longevity. Below is a detailed description of how this part fits with the specified Cummins engines.

Compatible Engines

• 4B3.9, 6B5.9, 6C8.3
• B3.9 G, B4.5, B5.9 CM2670 B166C, B5.9 G, B5.9 GAS PLUS CM556
• B6.7S, C GAS PLUS CM556, C8.3 G, G5.9, G5.9 CM558
• G8.3, G8.3 CM558, GTA8.3 CM558
• ISB3.9 CM2220 B107, ISB5.9 CM2880 B127, ISB5.9G CM2180, ISL G CM2180
• L GAS PLUS CM556, L8.9G CMOH2.0 L125B, L9.3 L105
• QSB3.9 30 CM550, QSB3.9 CM2880 B138

The 3934086 is designed to be compatible with a wide range of Cummins engines, ensuring that the rocker arms maintain the correct clearance, which is crucial for the smooth operation of the engine’s valve train.

Role of Part 3934086 in Engine Systems

The 3934086 is integral to the precise operation of several engine components, ensuring optimal performance and efficiency. This component is specifically designed to interact with the rocker lever, a pivotal element in the valve train mechanism of an engine.

Interaction with Rocker Lever

The rocker lever, also known as the rocker arm, is responsible for transferring motion from the camshaft to the valves. The 3934086 allows for fine-tuning of the clearance between the rocker lever and the valve stem. This adjustment is essential for maintaining the correct valve timing and ensuring that the valves open and close at the precise moments required for efficient engine operation.

Coordination with Rocker Lever Support

The rocker lever support, which holds the rocker lever in place, works in conjunction with the 3934086. Proper adjustment via the screw ensures that the rocker lever remains securely positioned on the support, minimizing wear and tear and enhancing the durability of the valve train components.

Influence on Rocker Levers

In engines with multiple cylinders, each cylinder typically has its own set of rocker levers. The 3934086 plays a role in synchronizing the operation of these levers. By allowing for micro-adjustments, it helps in balancing the valve operation across all cylinders, which is vital for smooth engine performance and consistent power delivery.

Impact on Valve Operation

Ultimately, the precise adjustment afforded by the 3934086 influences the overall valve operation. Proper valve timing is fundamental to engine efficiency, power output, and emissions control. The screw ensures that the valves open and close with the correct timing, which is crucial for the engine’s combustion process.

Conclusion

In summary, the 3934086 Rocker Lever Adjusting Screw is a key component in the valve train system, facilitating the accurate and efficient transfer of motion from the camshaft to the valves through the rocker lever and its support. Its role in fine-tuning the valve clearance is essential for the engine’s performance, durability, and overall efficiency.