This comprehensive service and repair manual is your complete guide to the Cummins Big Cam IV, New Big Cam IV, and 88 Big Cam IV NT855 diesel engines. It provides detailed information on every aspect of these engines, empowering you to perform repairs and maintenance with confidence.

Within this manual, you'll find in-depth coverage of essential components and systems, including:

* **Air Compressor:** Learn about the air compressor's operation, troubleshooting, and maintenance procedures.
* **Cam Follower Assembly:** Gain a thorough understanding of the cam follower assembly, its function, and how to inspect and replace it.
* **Capscrew Markings and Torque Values:** Find the correct torque values for all capscrews in the engine, ensuring proper assembly and preventing damage.
* **Cooling System - Torque Values:** Ensure proper cooling system operation with accurate torque values for all components.
* **Cylinder Block and Cylinder Head:** Explore the construction, operation, and troubleshooting procedures for the cylinder block and head.
* **Decimal and Metric Conversion Factors:** Easily convert between decimal and metric measurements using the provided conversion chart.
* **Drive Belt Tension Specifications:** Maintain optimal performance by adhering to the specific drive belt tension specifications.
* **Engine Assembly and Diagrams:** Understand the engine's assembly process and utilize detailed diagrams for visual support.
* **Engine Identification:** Learn how to correctly identify your Cummins diesel engine model.
* **Engine Testing:** Perform comprehensive engine testing procedures to diagnose issues and verify repairs.
* **Fan Hub Inspection Specifications:** Inspect and ensure the proper operation of the fan hub using detailed specifications.
* **Fuel Pump and Compressor Drive:** Explore the intricacies of the fuel pump and compressor drive system, including troubleshooting and maintenance.
* **General Engine Specifications:** Access essential data on the engine's specifications, performance, and operating parameters.
* **Injection Timing Codes:** Understand the meaning of injection timing codes and how to diagnose and correct timing issues.
* **Injectors:** Gain a comprehensive understanding of injector operation, maintenance, and troubleshooting techniques.
* **Lubricating Oil Pump and System:** Explore the lubricating oil system, including the oil pump, filters, and lubrication procedures.
* **Newton-Meter to Foot-Pound Conversion Chart:** Convert torque values between these units for accurate measurements.
* **Pipe Plug Torque Values:** Maintain sealing integrity with correct torque values for all pipe plugs.
* **Rocker Lever Housing Assembly:** Learn about the rocker lever housing assembly, its function, and how to inspect and repair it.
* **Service Literature Ordering Location:** Find information on ordering additional service literature for your specific engine model.
* **Specifications:** Access complete specifications for all engine components and systems.
* **Thermostat Housing Assembly and Thermostat (Reserve Flow Cooling):** Understand the operation and maintenance of the thermostat housing and reserve flow cooling system.
* **Turbocharger:** Learn about the turbocharger's function, troubleshooting, and maintenance procedures.
* **Valve and Injector Adjustments:** Perform precise valve and injector adjustments for optimal engine performance.
* **Vehicle Braking:** Explore the engine's role in the vehicle's braking system, including procedures for troubleshooting and maintenance.
* **Water Pump Assembly:** Understand the operation, maintenance, and troubleshooting procedures for the water pump assembly.
* **Weights and Measures:** Find essential weight and measure information for engine components and systems.

This manual provides a wealth of information to ensure you have the knowledge and expertise to maintain and repair your Cummins Big Cam IV, New Big Cam IV, and 88 Big Cam IV NT855 diesel engines with confidence.

The Cummins Big Cam IV, also known as the New Big Cam IV and 88 Big Cam IV NT855, is a renowned diesel engine that revolutionized the trucking industry. Introduced in the 1980s, the Big Cam IV was an advancement over its predecessor, the Cummins NTC-350, and quickly became a popular choice for heavy-duty trucks and other applications. It is a powerful and durable engine, known for its reliability and fuel efficiency. The Big Cam IV is a large-displacement engine, with a cubic inch capacity of 855, and boasts a legendary reputation for its ability to deliver substantial power and torque, even under demanding conditions. This engine's performance is attributed to the "Big Cam" design, which features a large camshaft with a higher lift and duration than previous models. This design provides increased valve timing, resulting in superior combustion efficiency and improved power output. Several variants of the Big Cam IV were produced, each with distinct power ratings and features. The New Big Cam IV, introduced in the 1990s, included significant improvements to the engine's design, particularly in the areas of emissions control and fuel economy.

The Big Cam IV utilized a variety of features that made it an exceptional engine for its time. Notably, it featured a robust cast-iron block and a cast-iron crankshaft, renowned for their exceptional durability and resistance to wear. The engine also incorporated a sophisticated fuel injection system, designed to deliver precise fuel metering for optimal combustion and efficiency. To facilitate maintenance and repair, the Big Cam IV was designed with a modular construction, allowing components to be easily removed and replaced. This simplified engine maintenance and facilitated repairs, reducing downtime and extending the engine's lifespan. The Big Cam IV's legacy lives on in the modern Cummins ISB engine, which incorporates many of the same design principles and technological innovations of its predecessor. The Big Cam IV's contributions to heavy-duty trucking are significant, paving the way for the powerful and efficient engines used in today's trucks.