When working on engines, especially in the world of diesel trucks, enthusiasts and mechanics often face questions about compatibility between different engine parts. One common question that arises, particularly for owners of Dodge Ram trucks, is whether a 5.9 valve cover will fit a 6.7 engine. Understanding whether engine components from different model years or engine sizes are interchangeable is crucial for proper maintenance and repair does a 5.9 valve cover fit n a 6.7.
In this article, we’ll explore the compatibility between the 5.9L and 6.7L engines, focusing on the valve covers, and explain why this is an important issue for diesel engine enthusiasts.
1. Overview of the 5.9L and 6.7L Cummins Engines
The 5.9L and 6.7L Cummins engines are both part of the well-known Cummins B-series family, widely used in Dodge Ram trucks, particularly in the heavy-duty diesel market. However, there are significant differences between the two engines, which affect compatibility between various parts.
5.9L Cummins Engine
- Displacement: 5.9 liters (359 cubic inches)
- Production Years: Primarily from 1989 to 2007 in Dodge Ram trucks.
- Common Applications: Known for its reliability and power, the 5.9L engine was used in many Ram 2500 and 3500 trucks.
- Features: The 5.9L Cummins is well-known for its mechanical fuel injection system in older models, which was replaced by electronic controls in later years.
6.7L Cummins Engine
- Displacement: 6.7 liters (409 cubic inches)
- Production Years: Introduced in 2007 and continues into the present for Dodge Ram trucks.
- Common Applications: The 6.7L engine is found in newer Ram 2500, 3500, and 4500 models.
- Features: The 6.7L Cummins is equipped with advanced technologies such as a high-pressure common-rail fuel system, a variable geometry turbocharger, and electronic controls for better emissions and efficiency.
While both engines are part of the Cummins family and share a similar design, the differences in displacement, fuel systems, and other technologies lead to certain variations in their components.
2. Valve Covers: What Are They and Why Are They Important?
A valve cover is an essential component in any internal combustion engine, as it seals the top of the cylinder head, protecting the valve train from contaminants like dirt and moisture. It also helps to keep oil contained in the engine and prevents leaks.
The valve cover plays an important role in engine health by maintaining the proper environment for the engine’s valves, camshafts, and rocker arms. Because of its location, the valve cover is often one of the first components that mechanics or enthusiasts might replace during an engine rebuild or modification.
3. Differences Between 5.9 and 6.7 Valve Covers
Design and Shape
One of the main factors affecting whether a 5.9 valve cover will fit a 6.7 engine is the design of the components. While the 5.9L and 6.7L engines are part of the same Cummins family, the 6.7L engine was designed with some significant upgrades, including changes to the cylinder head and fuel system. These modifications affect the design and shape of the valve cover.
- 5.9L Valve Cover: The 5.9 valve cover is designed to fit the specific dimensions and layout of the 5.9L Cummins cylinder head. It has a certain shape that matches the valve train components of the 5.9L engine.
- 6.7L Valve Cover: The 6.7L engine features a different valve cover design, primarily due to the new technology, such as the high-pressure fuel rail and changes in the valve train system. The 6.7L valve cover is typically wider and may have different bolt patterns compared to the 5.9L valve cover.
Mounting and Bolt Patterns
The mounting holes and bolt patterns are other important factors to consider. If the 5.9L valve cover has a different bolt pattern from the 6.7L, the valve covers will not be does a 5.9 valve cover fit n a 6.7 interchangeable, regardless of how similar the rest of the engine components may seem. In general, due to the design changes and advancements in the 6.7L, the bolt pattern is not the same as that of the 5.9L valve cover, making them incompatible without significant modification.
Breather and Emissions Ports
Another key difference is the inclusion of different breather and emissions ports. The 6.7L engine was introduced with stricter emissions regulations in mind, so it may include additional ports or fittings that the 5.9L valve cover does not have. For instance, the 6.7L may feature a port for the crankcase ventilation system or additional breather tubes, which would be absent on the 5.9L version.
4. Will a 5.9 Valve Cover Fit on a 6.7 Engine?
Given the differences in design, bolt patterns, and breather ports, a 5.9 valve cover will not directly fit on a 6.7 engine. While both engines belong to the same family, the specific changes made in the 6.7L’s design prevent direct interchangeability of parts like the valve cover.
If you are considering swapping or replacing the valve cover on your 6.7L Cummins engine, it is best to use a valve cover designed specifically for the 6.7L. Using a 5.9 valve cover on a 6.7 engine could lead to issues such as improper sealing, air and oil leaks, or interference with other engine components.
5. Can You Modify a 5.9 Valve Cover to Fit a 6.7 Engine?
While it’s technically possible to modify a 5.9 valve cover to fit a 6.7 engine, it is not recommended due to the complexities and potential issues that can arise. Modifying the valve cover may involve altering bolt holes, adjusting the shape of the cover, and potentially affecting the performance of the engine’s emissions and ventilation systems. These modifications can compromise the integrity and reliability of your engine, leading to more costly repairs down the road.
If you’re determined to use a 5.9 valve cover on a 6.7 engine, it’s essential to work with a qualified mechanic who can assess the necessary modifications and their impact on engine performance.
6. Conclusion
In conclusion, a 5.9 valve cover will not fit a 6.7 Cummins engine due to differences in design, bolt patterns, and emissions-related components. While both engines are part of the Cummins B-series, the 6.7L’s technological advancements and design changes make it incompatible with the 5.9L valve cover. For proper function, always use parts specifically designed for the engine in question.
If you need to replace your valve cover, ensure does a 5.9 valve cover fit n a 6.7 you’re using the correct part designed for the 6.7L Cummins to maintain engine performance and avoid unnecessary complications. Always consult your vehicle’s manual or speak to a professional mechanic for the best advice on replacement parts for your specific engine model.
