Cummins 855 Engine Swap Insights

[MikePhua]

When it comes to swapping engines, few names come up more frequently in heavy equipment discussions than the Cummins 855. Known for its durability and high performance, this engine is commonly used in a variety of applications from construction machinery to industrial equipment. This article aims to provide a comprehensive guide on the Cummins 855 engine swap process, including potential challenges, necessary modifications, and recommendations.
The Cummins 855 Engine: An Overview
The Cummins 855 is a 14-liter, 6-cylinder diesel engine, often referred to as a "Big Cam" engine due to its distinct design. First introduced in the 1970s, the 855 quickly gained a reputation for its robustness, efficiency, and ability to perform under heavy loads. With a displacement of 855 cubic inches, the engine provides significant power, often ranging from 250 to 400 horsepower depending on the variant. Over the years, Cummins has made several improvements, but the core engine remains one of the most reliable in the heavy equipment industry.
As with all high-performance engines, the Cummins 855’s reputation was built on its heavy-duty use in trucks, industrial machinery, and generators. Over its long run, this engine has powered everything from mining trucks to marine vessels, which is a testament to its versatility.
Common Reasons for an Engine Swap
There are various reasons why an operator or technician may decide to swap out the existing engine in a piece of equipment with the Cummins 855. Some of the most common reasons include:

1. Reliability Issues: If the original engine is constantly needing repairs, replacing it with a known quantity like the 855 can significantly improve operational uptime.
   
2. Power Upgrade: The 855 engine offers more power and torque than many standard engines, which is especially beneficial in heavy-duty equipment requiring higher output.
   
3. Fuel Efficiency: The 855, with its superior fuel economy, is an appealing choice for those looking to reduce operating costs over the life of the machine.
   

Challenges of the Cummins 855 Engine Swap
While the Cummins 855 is an excellent engine for heavy equipment applications, the swap process is not without its challenges. Here are some of the common obstacles one might encounter:

1. Engine Fitment: The 855 is a large engine, and fitting it into a machine that was originally designed for a smaller engine can be a tricky task. Depending on the model of the equipment, additional modifications to the engine compartment may be required.
   
2. Transmission Compatibility: The Cummins 855 engine typically works in tandem with specific transmission systems. When swapping engines, ensuring the transmission system is compatible with the new engine is crucial. A mismatch can lead to performance issues or even mechanical failure.
   
3. Mounting and Support: Engine mounts, brackets, and supports must be modified or replaced to accommodate the new engine. The Cummins 855 has a different weight distribution, so it's important to ensure the machine can handle the new setup.
   
4. Electrical and Wiring Systems: The 855 may require changes to the wiring harness, ECU, or fuel system. These components are crucial for the engine’s operation and must be integrated into the existing system for smooth performance.
   
5. Cooling System Modifications: With the increased power output of the 855 engine, it may require modifications to the cooling system, including a larger radiator or enhanced coolant lines to prevent overheating.
   

Recommended Modifications and Solutions
Given the challenges, it's essential to plan the swap carefully. Below are some recommendations for overcoming common obstacles:

1. Engine Mounting Kits: There are several engine mounting kits available that allow the Cummins 855 to be installed into various machines. These kits can include custom mounts, transmission adapters, and oil lines that ensure the engine fits snugly into place.
   
2. Transmission Adapters: If the existing transmission is not compatible with the 855, consider using an adapter kit designed to link the engine with your machine’s transmission. These kits are crucial for ensuring power transfer without damaging components.
   
3. Upgraded Fuel System: The 855 uses a mechanical fuel system, which may differ from modern, electronic systems found in some machines. A fuel system upgrade kit may be necessary to ensure the engine gets the proper fuel pressure and flow.
   
4. Electrical System Adjustments: Be prepared to modify the electrical system to meet the demands of the 855’s ignition and sensor requirements. This could involve replacing the ECU or integrating a new wiring harness designed for diesel engines.
   
5. Cooling Modifications: Increasing the engine’s cooling capacity is essential, especially under high-load conditions. Installing a more efficient radiator or an additional cooling fan can help keep the engine at optimal operating temperatures.
   

Alternative Engines for Similar Applications
While the Cummins 855 is an excellent choice for a swap, there are other engines that might be considered depending on the specific needs of the machine:

1. Caterpillar 3406: Another durable engine often found in heavy-duty equipment. The 3406 offers similar power output but may require different modifications in terms of fitment and systems.
   
2. Detroit Diesel 8V92: Known for its performance and reliability, this engine can be a suitable alternative if higher torque is required, though it's typically found in larger equipment and vehicles.
   
3. Perkins 6.354: A more compact engine that offers good fuel efficiency and power. This engine may be better suited to smaller machines.
   

Conclusion
Swapping to a Cummins 855 engine can be a game-changer for heavy equipment operators looking to improve power, reliability, and fuel efficiency. However, like any engine swap, it requires a thoughtful approach to overcome compatibility issues and ensure smooth integration. With the right modifications and planning, the Cummins 855 can be a long-lasting and high-performance solution for a wide variety of machines. Whether you're dealing with wear-and-tear issues or seeking a power upgrade, the 855 offers a proven track record in a wide range of industrial applications.