Compatibility between automotive parts like valve covers is a common concern for truck enthusiasts, especially those working on Dodge Ram Cummins diesel engines. If you’re wondering Does a 5.9 Valve Cover Fit on a 6.7 engine, you’re not alone. The answer isn’t as straightforward as a simple yes or no—it depends on specific factors like the model year, modifications, and your ultimate goal. Let’s dive deep into this topic to clarify everything you need to know.
Understanding the Basics: What Are Valve Covers?
Valve covers play a critical role in the engine’s operation. They sit atop the cylinder head, protecting the valves, springs, and rocker arms while sealing the oil inside. This helps prevent oil leaks and contamination from debris. On Cummins diesel engines, valve covers also contribute to engine aesthetics, with some enthusiasts opting for custom covers for style and durability.
5.9 vs. 6.7 Cummins Engines: Key Differences
The Cummins 5.9L and 6.7L engines share a lineage but have notable differences:
- 5.9L Cummins
- Production: 1984–2007
- Displacement: 5.9 liters
- Features: No factory emissions systems on earlier models, simpler design
- 6.7L Cummins
- Production: 2007–present
- Displacement: 6.7 liters
- Features: Advanced emissions systems (EGR, DPF), larger size, more power output
The design variations between these engines impact the compatibility of parts like valve covers.
Does a 5.9 Valve Cover Fit on a 6.7?
Technically, a 5.9 valve cover does not directly fit on a 6.7 without modifications. Here’s why:
- Dimensional Differences
The 6.7 engine is larger, with changes in head design that affect how components like valve covers mount. - Mounting Points
The bolt patterns and mounting locations differ slightly between the two engines, which prevents a direct swap. - Sealing Issues
Even if you manage to install a 5.9 valve cover, it may not seal properly, leading to potential oil leaks. - Emissions Considerations
The 6.7 valve covers often integrate components for emissions systems, which the 5.9 lacks.
Why Consider Swapping Valve Covers?
Some enthusiasts attempt this swap for various reasons:
- Aesthetic Appeal: The simpler design of the 5.9 valve cover can look cleaner.
- Custom Modifications: Builders may prefer the 5.9 cover for custom setups.
- Cost Savings: 5.9 covers are sometimes more affordable and readily available.
Modifications Needed for Compatibility
If you’re determined to fit a 5.9 valve cover on a 6.7, prepare for some modifications:
- Adjust Mounting Points: Custom brackets or adapters may be needed.
- Seal Adjustments: Use high-quality gaskets and possibly custom seals to prevent leaks.
- Clearance Checks: Ensure no interference with other components, such as injectors or fuel lines.
Potential Risks of Incompatibility
- Oil Leaks: Improper sealing can result in engine damage.
- Emissions Violations: In some regions, altering emissions-related parts can be illegal.
- Performance Issues: Misaligned or improperly secured covers can affect engine performance.
Alternatives to Swapping
If compatibility issues deter you, consider these alternatives:
- Aftermarket Valve Covers: Many companies offer custom-fit options for both 5.9 and 6.7 engines.
- Powder Coating or Custom Painting: Personalize your existing 6.7 cover without compromising fit or function.
- OEM Replacement Covers: Stick with factory-fit parts designed for your engine.
FAQs
Does a 5.9 valve cover bolt pattern match the 6.7?
No, the bolt patterns differ slightly, requiring modifications for compatibility.
Can a 5.9 valve cover handle the pressure of a 6.7 engine?
While possible, it may not be optimal without ensuring a proper seal and adjustments.
Are there aftermarket solutions for better compatibility?
Yes, aftermarket manufacturers offer valve covers that blend aesthetics with perfect fitment for 6.7 engines.
Is it worth the effort to swap valve covers?
It depends on your goals. For aesthetics or cost savings, it may be worth it, but risks like leaks should be considered.
What are the key differences between 5.9 and 6.7 valve covers?
Design, mounting points, and emissions compatibility are primary differences.
Does swapping valve covers void the warranty?
Yes, any non-OEM modification can void the manufacturer’s warranty in most cases.
Conclusion
While a 5.9 valve cover doesn’t fit a 6.7 Cummins engine directly, enthusiasts can explore modifications or alternatives to achieve their goals. Understanding the differences between these engines and their components is crucial before attempting any changes. Whether you’re looking for a performance upgrade or a style statement, evaluating risks and rewards will help ensure a successful outcome.
