3929021
Main Bearing
Cummins®

The Cummins 3929021 Main Bearing is a component designed for use in heavy-duty truck engines. It supports the crankshaft and facilitates smooth rotation with minimal friction, which is essential for the engine’s efficiency and longevity. This bearing ensures that the truck performs reliably under demanding conditions.

Basic Concepts of Main Bearings

Main bearings are components found in internal combustion engines that support the crankshaft. Their primary function is to allow the crankshaft to rotate with minimal friction, which is crucial for the engine’s performance and durability. By providing a stable and low-friction interface between the crankshaft and the engine block, main bearings help to distribute the engine’s load and reduce wear on the crankshaft journals ¹.

Purpose of the Cummins 3929021 Main Bearing

The Cummins 3929021 Main Bearing is specifically engineered to support the crankshaft in heavy-duty truck engines. It enables the crankshaft to rotate smoothly, which is essential for the engine’s overall performance. By reducing friction between the crankshaft and the engine block, this bearing helps to minimize wear and tear, contributing to the engine’s longevity and efficiency ².

Key Features of the Cummins 3929021 Main Bearing

The Cummins 3929021 Main Bearing is characterized by its robust design and high-quality materials. It is constructed to withstand the high loads and temperatures encountered in heavy-duty truck engines. The bearing’s design includes precision-machined surfaces and high-quality bearing materials that enhance its performance and durability. These features ensure that the bearing can operate efficiently under demanding conditions, providing reliable support for the crankshaft ³.

Benefits of Using Cummins 3929021 Main Bearings

Utilizing Cummins 3929021 Main Bearings in heavy-duty truck engines offers several advantages. These bearings contribute to improved engine efficiency by reducing friction and wear on the crankshaft. They also enhance the engine’s reliability, ensuring consistent performance over time. Additionally, the durability of these bearings helps to minimize maintenance requirements and extend the engine’s operational lifespan.

Installation and Maintenance

Proper installation of the Cummins 3929021 Main Bearing is crucial for ensuring its optimal performance. It is recommended to follow manufacturer guidelines for installation procedures and to use the appropriate tools. Regular maintenance, including periodic inspections and lubrication, is essential to ensure the bearing operates efficiently throughout its lifespan. Adhering to these practices helps to prevent premature wear and ensures the bearing continues to support the crankshaft effectively.

Troubleshooting Common Issues

Common problems associated with main bearings include noise, excessive wear, and failure symptoms. These issues can often be identified through careful inspection and diagnostic testing. Addressing these problems may involve cleaning or replacing the bearing, ensuring proper lubrication, and checking for misalignment or other mechanical issues. Timely identification and resolution of these problems are important for maintaining the engine’s performance and longevity.

Manufacturer Overview - Cummins Inc.

Cummins Inc. is a leading manufacturer in the heavy-duty truck industry, known for its wide range of high-quality engine components. With a history of innovation and excellence, Cummins has established a strong reputation for producing reliable and durable parts. The company’s product range includes engines, filtration systems, and aftermarket parts, all designed to meet the demanding requirements of heavy-duty applications. Cummins’ commitment to quality and performance makes it a trusted name in the industry.

Cummins Main Bearing Part 3929021 Compatibility

The Cummins main bearing part number 3929021 is designed to ensure smooth and reliable engine operation. This part is compatible with a variety of Cummins engines, each tailored for different applications and performance requirements. Here is a detailed overview of the engines with which this main bearing part is compatible:

4B3.9 and 6B5.9 Engines

The 4B3.9 and 6B5.9 engines are part of the B-Series family, known for their robust design and efficiency. The main bearing part 3929021 fits seamlessly into these engines, providing the necessary support and stability for the crankshaft.

B3.9 G, B4.5, and B4.5 RGT Engines

These engines are also part of the B-Series family, with the “G” and “RGT” designations indicating specific configurations. The part 3929021 is designed to fit these engines, ensuring optimal performance and longevity.

B5.9 G and B5.9 GAS PLUS CM556 Engines

The B5.9 G and B5.9 GAS PLUS CM556 engines are high-performance variants within the B-Series. The main bearing part 3929021 is engineered to meet the demands of these engines, providing reliable support and reducing wear.

B6.7 G CMOH6.0 B125, B6.7S, and G5.9 Engines

These engines, including the B6.7 G CMOH6.0 B125, B6.7S, and G5.9, are part of the larger B-Series and C-Series families. The part 3929021 is compatible with these engines, ensuring smooth operation and durability.

G5.9 CM558, ISB (Chrysler), and ISB CM2150 Engines

The G5.9 CM558, ISB (Chrysler), and ISB CM2150 engines are part of the ISB family, known for their versatility and power. The main bearing part 3929021 fits these engines, providing the necessary support for their demanding applications.

ISB CM550, ISB CM850, and ISB/ISD6.7 CM2150 SN Engines

These engines, including the ISB CM550, ISB CM850, and ISB/ISD6.7 CM2150 SN, are part of the ISB family. The part 3929021 is designed to fit these engines, ensuring reliable performance and longevity.

ISB3.9 CM2220 B107, ISB6.7 CM2250, and ISBE CM2150 Engines

The ISB3.9 CM2220 B107, ISB6.7 CM2250, and ISBE CM2150 engines are part of the ISB and ISBE families. The main bearing part 3929021 is compatible with these engines, providing the necessary support for their specific applications.

ISBE CM800, ISBE4 CM850, QSB3.9 30 CM550, and QSB3.9 CM2880 B138 Engines

The ISBE CM800, ISBE4 CM850, QSB3.9 30 CM550, and QSB3.9 CM2880 B138 engines are part of the QSB and ISBE families. The part 3929021 is designed to fit these engines, ensuring smooth operation and durability.

QSB4.5 CM850 (CM2850) and QSB5.9 30 CM550 Engines

The QSB4.5 CM850 (CM2850) and QSB5.9 30 CM550 engines are part of the QSB family. The main bearing part 3929021 is compatible with these engines, providing the necessary support for their demanding applications.

This comprehensive compatibility ensures that the Cummins main bearing part 3929021 can be used across a wide range of engines, providing reliable performance and durability.

Role of Part 3929021 Main Bearing in Engine Systems

The part 3929021 Main Bearing is an essential component in various engine configurations, facilitating smooth operation and longevity of the engine’s core components.

In the cylinder block and engine block, the main bearing ensures that the crankshaft rotates with minimal friction. This is vital for the efficient transfer of power from the pistons to the crankshaft, which in turn drives the vehicle.

When integrated into a short block or long block assembly, the main bearing supports the crankshaft within the engine block, allowing for precise alignment and rotation. This is particularly important in configurations such as the short 4BT, short 4BTA, short 6BT, and short E2 215/235 block, where the engine’s compact design demands high precision and reliability.

In an overhaul kit or pistonless overhaul scenario, the main bearing is often replaced to ensure that the refurbished engine operates as smoothly as a new one. Its role becomes even more pronounced in high-performance or high-stress environments, such as those found in short E2 incentive or short E3 incentive blocks, where durability and consistent performance are paramount.

The main bearing also interacts with the crankshaft thrust bearing kit, working in tandem to manage axial loads and prevent crankshaft movement along the engine’s centerline. This collaboration is essential in maintaining the integrity of the engine’s rotating assembly.

Overall, the part 3929021 Main Bearing is a foundational element in the engine’s mechanical system, ensuring that the crankshaft operates efficiently within the engine block, thereby contributing to the overall performance and reliability of the engine.

Conclusion

The Cummins 3929021 Main Bearing is a critical component in heavy-duty truck engines, designed to support the crankshaft and facilitate smooth rotation with minimal friction. Its robust design and high-quality materials ensure reliable performance and durability under demanding conditions. Proper installation and maintenance are essential to maximize the benefits of this bearing, contributing to the engine’s efficiency, reliability, and longevity.