3947574
Belt Tensioner
Cummins®

The Cummins 3947574 Belt Tensioner is a component designed for use in commercial trucks. Its purpose is to maintain the correct tension on the belts that drive various accessories in the engine system, ensuring they operate efficiently and reliably.

Basic Concepts of Belt Tensioners

A belt tensioner is a device used in an engine system to keep belts at the proper tension. It functions by applying consistent pressure to the belt, which helps in reducing slippage and wear. Proper belt tension is important for the efficient transfer of power from the engine to accessories such as the alternator, water pump, and air conditioning compressor ¹.

Purpose of the 3947574 Belt Tensioner

This Cummins part plays a specific role in the operation of a truck by maintaining the necessary tension on the belts within the engine’s accessory drive system. This ensures that accessories receive consistent power transmission, which is vital for their proper function and the overall performance of the truck ².

Key Features

The design and construction of the 3947574 Belt Tensioner include features such as durable materials that resist wear and corrosion, a mechanism that automatically adjusts tension as the belt stretches or contracts, and a robust build that can withstand the rigors of commercial truck operation. These attributes contribute to the tensioner’s reliability and longevity ³.

Benefits of Using the 3947574 Belt Tensioner

Using this part provides several advantages. It contributes to improved efficiency of the accessory drive system by ensuring belts remain taut. This reduces the likelihood of belt slippage and wear, leading to enhanced reliability and potentially extending the lifespan of both the belts and the accessories they drive.

Installation and Compatibility

Proper installation of the 3947574 Belt Tensioner involves following manufacturer guidelines to ensure it is securely mounted and correctly aligned with the belt and pulleys. While specific tools and precautions may be necessary, adherence to these instructions helps in achieving optimal performance and compatibility with the truck’s engine system.

Troubleshooting Common Issues

Common problems associated with belt tensioners include noise, slippage, or failure. Diagnostic steps may involve inspecting the tensioner for signs of wear or damage, checking the belt for proper tension and condition, and ensuring all components are correctly aligned and installed. Solutions may range from simple adjustments to replacement of worn parts.

Maintenance Tips

Regular maintenance practices for the 3947574 Belt Tensioner include periodic inspections to check for wear, proper tension, and alignment. Following manufacturer-recommended inspection intervals and replacement guidelines can help ensure the tensioner continues to operate effectively, contributing to the longevity and optimal performance of the accessory drive system.

Cummins Corporation

Cummins Inc. is a well-established manufacturer in the commercial truck industry, known for its wide range of products including engines, filtration, and power generation equipment. The company has a reputation for quality and reliability, backed by a history of innovation and commitment to customer satisfaction.

Belt Tensioner 3947574 Compatibility with Cummins Engines

The Belt Tensioner part number 3947574, manufactured by Cummins, is designed to fit a variety of Cummins engines. Here is a breakdown of the compatibility of this part with the listed engines:

D4.0 CM2620 D103B, F3.8 CM2350 F120B, F3.8 CM2620 F137B, F4.5 CM2620 F139B, F4.5 CM2620 F141C

The Belt Tensioner 3947574 is compatible with the following engines:

• D4.0 CM2620 D103B
• F3.8 CM2350 F120B
• F3.8 CM2620 F137B
• F4.5 CM2620 F139B
• F4.5 CM2620 F141C

These engines share similar design elements and specifications, making the belt tensioner a suitable fit for all listed models.

ISB (Chrysler), ISB CM850

The Belt Tensioner 3947574 is also compatible with:

• ISB (Chrysler)
• ISB CM850

These engines, while distinct from the previous group, are designed to work with the same belt tensioner due to shared engineering principles.

ISF3.8 CM2220 AN, ISF3.8 CM2220 F103, ISF3.8 CM2350 F109, ISF4.5 CM2220 F123

The following engines are also compatible with the Belt Tensioner 3947574:

• ISF3.8 CM2220 AN
• ISF3.8 CM2220 F103
• ISF3.8 CM2350 F109
• ISF4.5 CM2220 F123

These engines share common characteristics that allow the belt tensioner to function effectively.

QSF3.8 CM2880 F112

The Belt Tensioner 3947574 is compatible with:

• QSF3.8 CM2880 F112

This engine, while different in some aspects, is designed to work with the same belt tensioner due to its engineering specifications.

ISV (Nissan)

The Belt Tensioner 3947574 is also compatible with:

• ISV (Nissan)

This engine, despite being a Nissan variant, is designed to fit the same belt tensioner due to shared design elements and specifications.

Role of Part 3947574 Belt Tensioner in Engine Systems

The 3947574 Belt Tensioner is an essential component in maintaining the proper function of various engine systems. It ensures that the drive belt is kept at the correct tension, which is vital for the efficient operation of several engine-driven accessories.

Interaction with the Drive System

In the drive system, the 3947574 Belt Tensioner works in conjunction with the drive belt to transfer power from the engine to various components. By maintaining the appropriate tension on the belt, it prevents slippage and ensures consistent power transmission. This is particularly important for components like the water pump and alternator, which rely on a steady supply of power to function correctly.

Coordination with the Water Pump

The water pump is a key component in the engine’s cooling system. It circulates coolant through the engine to prevent overheating. The 3947574 Belt Tensioner plays a significant role here by ensuring that the belt driving the water pump maintains the necessary tension. This consistent tension allows the water pump to operate efficiently, providing reliable coolant circulation.

Integration with the Long Block Kit

When installing a long block kit, which includes the engine block, crankshaft, pistons, and other essential components, the 3947574 Belt Tensioner is instrumental in setting up the drive system. Proper tensioning of the belt is required to ensure that all driven components, such as the water pump and alternator, are correctly powered once the engine is assembled and running.

Function in the Tensioner System

The 3947574 Belt Tensioner is part of a broader tensioner system designed to automatically adjust the tension on the belt as it wears or stretches over time. This self-adjusting feature helps maintain optimal belt tension, reducing the need for manual adjustments and enhancing the longevity and performance of the drive belt.

Relationship with the Belt

The belt itself is a critical link in the drive system, transferring power from the engine to various accessories. The 3947574 Belt Tensioner ensures that this belt remains taut, minimizing the risk of belt failure and maximizing the efficiency of power transfer. Proper tensioning also reduces wear on the belt, extending its service life.

Support for the Water Pump Drive

The water pump drive is directly influenced by the performance of the 3947574 Belt Tensioner. Consistent belt tension ensures that the water pump receives a steady drive, allowing it to maintain a consistent flow of coolant. This is essential for preventing engine overheating and ensuring the engine operates within safe temperature ranges.

Conclusion

In summary, the 3947574 Belt Tensioner is a vital component that ensures the drive belt maintains the correct tension, supporting the efficient operation of the drive system, water pump, and other engine-driven accessories. Its role in the tensioner system helps maintain optimal belt performance and contributes to the overall reliability of the engine.