3900068
Ring Dowel
Cummins®

The Cummins 3900068 Ring Dowel is a component designed to enhance the operational efficiency of commercial trucks. Its purpose is to ensure precise alignment and secure fitting of various engine components, contributing to the overall reliability and performance of the vehicle.

Basic Concepts of Ring Dowels

A ring dowel is a mechanical fastener used to align and position components within an assembly. It operates by providing a fixed reference point that other parts can align with, ensuring that components are correctly positioned relative to each other. In engines and other machinery, ring dowels help maintain the integrity of the assembly by preventing misalignment, which can lead to wear, reduced efficiency, and potential failure of the system ¹.

Role of the 3900068 Ring Dowel in Truck Operation

The Cummins 3900068 Ring Dowel plays a specific role in the operation of a truck by ensuring the accurate alignment of engine components. It is typically placed in strategic locations within the engine block or other critical areas where precise fitting is required. By interacting with other components, such as cylinder heads or bearing caps, the ring dowel helps to maintain the structural integrity and operational efficiency of the engine ².

Key Features

The Cummins 3900068 Ring Dowel is characterized by several key features that enhance its functionality. These include its material composition, which is typically a durable metal alloy designed to withstand high stress and temperatures. The design specifications of the ring dowel ensure it fits securely into its designated location, providing a stable reference point for other components. Additionally, any unique attributes, such as specialized coatings or precision machining, further contribute to its reliability and performance.

Benefits

The Cummins 3900068 Ring Dowel offers several benefits that contribute to the overall efficiency and durability of a truck’s engine. By ensuring improved alignment of components, it helps to reduce wear and tear, leading to longer-lasting engine parts. Enhanced durability is achieved through its robust construction, which can withstand the rigors of commercial truck operation. Furthermore, the precise alignment facilitated by the ring dowel contributes to overall engine efficiency, potentially improving fuel economy and performance ³.

Troubleshooting and Maintenance

Common issues associated with ring dowels may include wear, corrosion, or improper installation. Troubleshooting these problems involves inspecting the ring dowel for signs of damage or misalignment and addressing any issues promptly to prevent further complications. Maintenance practices for the Cummins 3900068 Ring Dowel include regular inspection during engine servicing, cleaning to remove any debris or contaminants, and replacement if significant wear or damage is detected. These practices help ensure the longevity and optimal performance of the ring dowel and the engine as a whole.

Compatibility with Cummins Engines

The Ring Dowel part 3900068, manufactured by Cummins, is compatible with a variety of Cummins engines, ensuring proper piston ring alignment and function within the engine. This part is utilized across different engine series and configurations, including but not limited to:

• 15N CM2380 M104B
• 4B3.9, B4.5, B4.5 CM2350 B129B, B4.5 RGT
• 6B5.9, B5.9, B5.9 GAS PLUS CM556, B5.9 CM2670 B166C, B5.9 G
• B6.7, B6.7 CM2350 B135B, B6.7 CM2670 B153B, B6.7 CM2670 B164C, B6.7 G CMOH6.0 B125, B6.7S
• D4.0 CM2620 D103B
• F2.8 CM2620 F135B
• F3.8, F3.8 CM2350 F120B, F3.8 CM2350 F128C, F3.8 CM2620 F137B, F3.8 F102
• F4.5, F4.5 CM2620 F139B, F4.5 CM2620 F141C
• G5.9

The 3900068 is designed to fit seamlessly into these engines, ensuring that the piston rings maintain their correct position and function, which is essential for optimal engine performance and longevity.

Role of Part 3900068 Ring Dowel in Engine Systems

The Part 3900068 Ring Dowel is a critical component in various engine systems, ensuring proper alignment and structural integrity between mating parts. Its role can be observed across several engine configurations and components:

• Cylinder Block and Short Block Assemblies: In configurations such as the Block 6-B Short, Block Service, Short 4BTA, Short 6-BT, Short 6BT, Short E2 Incent, and Short E1 180 Block, the ring dowel ensures that the cylinder block aligns correctly with other components, such as the cylinder head and main bearing caps. This alignment is vital for the engine’s operational efficiency and durability.

• Cylinder Head and Gear Housing: When interfacing with the Cylinder Head and Gear Housing, the ring dowel maintains the precise spacing required for optimal engine performance. This is particularly important in engines like the Short E2 215/235 Block and Short E2 Block, where even minor misalignments can lead to significant performance issues.

• Front and Rear Gear Covers: In systems involving the Front Gear Cover and NEF Rear Gear, the ring dowel plays a key role in ensuring that these covers are properly seated. This is essential for the smooth operation of the engine’s gear train and overall mechanical harmony.

• Hardware Kit Block and Housing: The ring dowel is also integral in the Hardware Kit Block and various Housing components. It ensures that all hardware is correctly positioned, which is critical for the structural integrity and function of the engine block.

• Long Block Kit and Main Bearing Cap: In the context of a Long Block Kit, the ring dowel assists in the accurate placement of the Main Bearing Cap. This is essential for maintaining the proper clearances and load distribution within the engine.

• Rear Clutch and Rocker Lever Shaft: For components like the Rear Clutch and Rocker Lever Shaft, the ring dowel helps in achieving the necessary alignment, which is crucial for the efficient transfer of power and smooth operation of the valve train.

Conclusion

In summary, the Cummins 3900068 Ring Dowel is a fundamental component in ensuring the correct alignment and structural integrity of various engine systems, contributing to the overall performance and reliability of the engine. Regular maintenance and prompt troubleshooting of any issues associated with this part are essential for maintaining the longevity and efficiency of the engine.