The Cummins Big Cam III and Big Cam IV NT 855 Diesel Engine Troubleshooting and Repair Manual is a comprehensive guide for technicians and mechanics working on these powerful engines. This detailed manual contains everything you need to diagnose, repair, and maintain your Cummins Big Cam III and Big Cam IV, NT 855 Diesel Engine. It covers a wide range of topics, including:

* **Engine Identification:** Learn how to properly identify your specific engine model and its unique features.
* **Troubleshooting:** This section provides step-by-step guidance to diagnose and resolve a variety of engine problems.
* **Cooling System:** Understand the intricacies of the cooling system, including troubleshooting common issues and performing necessary maintenance.
* **Lubricating Oil System:** Explore the essential components of the oil system, troubleshoot potential problems, and learn proper maintenance procedures.
* **Combustion Air System:** This section delves into the critical air intake system, providing troubleshooting tips and maintenance recommendations.
* **Compressed Air System:** Gain insights into the compressed air system used for various engine functions, including troubleshooting and maintenance.
* **Fuel System:** Detailed coverage of the fuel system, including troubleshooting common issues and understanding fuel injection procedures.
* **Electrical System:** A comprehensive guide to the electrical components and wiring diagrams, enabling you to diagnose and repair electrical problems.
* **Base Engine Components:** Thorough explanations and repair procedures for all essential engine components, including the block, crankshaft, and cylinder heads.
* **Engine Testing:** Learn how to test your engine properly on a chassis, ensuring proper functionality and performance.
* **Engine Removal and Installation:** Detailed instructions on how to safely remove and reinstall the engine, covering all critical steps.
* **Engine Component Specifications:** Complete specifications and tolerances for all engine components, ensuring accurate repairs and replacements.

This manual also features an alphabetical index and a section on additional service literature for further reference. You will find real-world photos and illustrations throughout the book, making it easier to understand complex concepts and perform repairs confidently.

The Cummins Big Cam III and Big Cam IV NT 855 diesel engines are renowned for their robust construction, high performance, and durability, making them a popular choice for heavy-duty applications. These engines boast a displacement of 8.55 liters and feature the signature Cummins "Big Cam" design with a large valvetrain for increased airflow and power. The Big Cam III, introduced in the mid-1980s, was known for its reliable performance and fuel efficiency. The Big Cam IV, which succeeded it in the early 1990s, further enhanced these attributes with advancements in engine management systems and emissions control technologies. The NT 855 series engines found extensive use in a wide range of vehicles, including trucks, buses, construction equipment, and marine applications. These engines delivered power outputs ranging from 250 to 500 horsepower, depending on the configuration and application.

The Cummins Big Cam III and Big Cam IV NT 855 engines are characterized by their robust construction, utilizing a durable cast iron block and cylinder heads. The engine design incorporates a common rail fuel injection system, which precisely controls fuel delivery for optimized performance and emissions. This, combined with the advanced engine management systems, ensures smooth operation and reliable performance under demanding conditions. Both the Big Cam III and Big Cam IV models were available with various configurations, including different turbocharger options and exhaust gas recirculation (EGR) systems to meet evolving emissions regulations. Their enduring popularity and reputation for reliability and performance have solidified their position as enduring workhorses in the heavy-duty industry.