3920781
Hexagon Flange Head Cap Screw
Cummins®

Introduction

The Hexagon Flange Head Cap Screw, specifically Part #3920781 by Cummins, is a vital component in the realm of heavy-duty trucks. Cummins, a renowned manufacturer in the automotive industry, produces this screw to meet the demanding requirements of heavy-duty applications. This screw is designed to provide reliable fastening solutions, ensuring the integrity and performance of various truck components.

Basic Concepts

A Hexagon Flange Head Cap Screw is a type of fastener characterized by its hexagonal head and flanged design. The hexagonal head allows for efficient torque application using standard tools, while the flange provides additional surface area to distribute load and prevent the screw from sinking into the material. This screw functions by securely joining two or more components together, playing a role in maintaining structural integrity and operational efficiency in fastening applications ¹.

Purpose and Role in Truck Operation

The 3920781 Hexagon Flange Head Cap Screw plays a specific role in the operation and maintenance of heavy-duty trucks. It is used in applications where high tensile strength and resistance to vibration are required. This screw helps in securing critical components, ensuring they remain firmly in place under various operating conditions. Its design contributes to the overall reliability and durability of the truck, facilitating efficient performance and reducing the risk of component failure ².

Key Features

The 3920781 Hexagon Flange Head Cap Screw boasts several key features that enhance its functionality:

• Hexagonal Head: Allows for easy and precise torque application using common tools.
• Flange Design: Provides additional bearing surface, which helps in distributing the load and preventing the screw from pulling through the material.
• Material Properties: Constructed from high-quality materials, this screw offers excellent tensile strength, corrosion resistance, and durability, making it suitable for demanding environments ³.

Benefits

The 3920781 Hexagon Flange Head Cap Screw offers several benefits:

• Enhanced Fastening Security: The flange design and hexagonal head work together to provide a secure fastening solution, reducing the likelihood of loosening over time.
• Resistance to Vibration: Its design minimizes the effects of vibration, which is common in heavy-duty truck applications, thereby maintaining a tight and secure connection.
• Ease of Installation: The hexagonal head allows for straightforward installation and removal using standard tools, facilitating quick and efficient maintenance procedures.

Installation Process

To ensure optimal performance and longevity, follow these steps for proper installation of the 3920781 Hexagon Flange Head Cap Screw:

1. Prepare the Surface: Ensure the mating surfaces are clean and free from debris to achieve a proper fit.
2. Align the Screw: Position the screw in the designated hole, ensuring it is correctly aligned with the components to be joined.
3. Apply Torque: Use a torque wrench to apply the recommended torque specification. This ensures the screw is tightened to the appropriate level without over-tightening, which could lead to damage.
4. Inspect the Installation: After installation, inspect the screw to confirm it is securely fastened and the flange is properly seated against the surface.

Troubleshooting Common Issues

Common problems associated with Hexagon Flange Head Cap Screws include loosening, corrosion, and damage. To address these issues:

• Loosening: Re-tighten the screw to the specified torque. If loosening persists, inspect for potential causes such as vibration or inadequate surface preparation.
• Corrosion: Clean the screw and surrounding area. Applying a corrosion-resistant coating can help prevent future issues.
• Damage: Inspect the screw for signs of wear or damage. Replace the screw if necessary to maintain structural integrity.

Maintenance Tips

To prolong the lifespan of the 3920781 Hexagon Flange Head Cap Screw:

• Regular Inspections: Periodically check the screw for signs of loosening, corrosion, or damage.
• Torque Checks: Ensure the screw maintains the correct torque over time. Re-torque as needed to prevent loosening.
• Cleaning: Keep the screw and surrounding area clean to prevent buildup of debris that could affect performance.

Cummins Overview

Cummins is a leading manufacturer in the automotive industry, known for its commitment to quality and innovation. With a rich history spanning several decades, Cummins offers a wide range of products designed to meet the needs of various applications, including heavy-duty trucks. Their focus on durability, performance, and reliability ensures that their components, like the 3920781 Hexagon Flange Head Cap Screw, deliver consistent and dependable performance in demanding environments.

Cummins Engine Compatibility with Hexagon Flange Head Cap Screw Part 3920781

The Cummins part 3920781, a Hexagon Flange Head Cap Screw, is a versatile component that fits into various Cummins engine models. This screw is designed to secure different parts within the engine, ensuring structural integrity and proper functioning. Here is a detailed look at the compatibility of this screw with various Cummins engines:

4B3.9 and 6B5.9 Engines

The 4B3.9 and 6B5.9 engines are part of the B Series engines, known for their reliability and performance. The Hexagon Flange Head Cap Screw part 3920781 is used in these engines to secure various components, ensuring that the engine’s internal parts remain tightly fastened and properly aligned.

B3.9 G, B4.5, B5.9 CM2670 B166C, B5.9 G, B5.9 GAS PLUS CM556, B6.7S, G5.9, G5.9 CM558

These engines, including the B3.9 G, B4.5, B5.9 CM2670 B166C, B5.9 G, B5.9 GAS PLUS CM556, B6.7S, G5.9, and G5.9 CM558, also benefit from the use of the Hexagon Flange Head Cap Screw part 3920781. This screw is crucial in maintaining the structural integrity of these engines by securing various parts, including those that are exposed to high stress and temperature.

ISB3.9 CM2220 B107, ISB5.9 CM2880 B127, ISB5.9G CM2180

The ISB Series engines, such as the ISB3.9 CM2220 B107, ISB5.9 CM2880 B127, and ISB5.9G CM2180, utilize the Hexagon Flange Head Cap Screw part 3920781 to ensure that critical components are securely fastened. This screw is essential in maintaining the alignment and stability of the engine’s internal parts, contributing to the overall performance and longevity of the engine.

QSB3.9 30 CM550, QSB3.9 CM2880 B138, QSB5.9 30 CM550, QSB5.9 CM2880 B139, QSB5.9 CM550, QSB5.9G

The QSB Series engines, including the QSB3.9 30 CM550, QSB3.9 CM2880 B138, QSB5.9 30 CM550, QSB5.9 CM2880 B139, QSB5.9 CM550, and QSB5.9G, also incorporate the Hexagon Flange Head Cap Screw part 3920781. This screw is used to secure various components within these engines, ensuring that the engine operates smoothly and efficiently. Its design allows for easy installation and removal, making it a practical choice for maintenance and repairs.

Hexagon Flange Head Cap Screw in Engine Systems

The Hexagon Flange Head Cap Screw (part 3920781) is integral to the assembly and maintenance of various engine components. Its design allows for secure fastening, which is essential for the reliable operation of engine systems.

Cylinder Head Assembly

In the cylinder head assembly, the Hexagon Flange Head Cap Screw is used to fasten the head to the engine block. This ensures a tight seal, preventing coolant and oil leaks, and maintaining compression within the combustion chambers. The flange head design provides additional surface area for torque application, enhancing the screw’s ability to withstand the high pressures and temperatures present in the cylinder head.

Leak Test Kit Integration

When utilizing a leak test kit to check for gasket or seal integrity, the Hexagon Flange Head Cap Screw plays a supporting role. It secures the test apparatus to the engine, ensuring that the test environment remains stable and that any detected leaks are accurately assessed. The robust nature of the screw helps in maintaining the structural integrity of the test setup under varying pressure conditions.

Lever and Rocker Mechanisms

In lever and rocker mechanisms, the Hexagon Flange Head Cap Screw is employed to attach these components to the engine block or other structural elements. This is particularly important in valve train systems where precise alignment and secure fastening are necessary for optimal valve operation. The screw’s flange head provides additional stability, reducing the risk of loosening over time due to engine vibrations.

Rocker Lever Applications

For rocker levers, the Hexagon Flange Head Cap Screw ensures that the lever is firmly attached to its pivot point. This is vital for consistent valve actuation, which directly impacts engine performance and efficiency. The screw’s design allows for easy adjustment and re-torquing, facilitating maintenance and repair processes without compromising the integrity of the fastening.

Overall, the Hexagon Flange Head Cap Screw (part 3920781) is a versatile fastener that enhances the reliability and performance of various engine components through secure and stable connections.

Conclusion

The 3920781 Hexagon Flange Head Cap Screw by Cummins is a critical component in the maintenance and operation of heavy-duty trucks and various Cummins engines. Its design, featuring a hexagonal head and flange, provides secure fastening, resistance to vibration, and ease of installation. Proper installation, regular maintenance, and troubleshooting common issues ensure the longevity and reliability of this essential fastener. Cummins’ commitment to quality and innovation is evident in the performance and durability of this part, making it a trusted choice for demanding applications.