When upgrading or maintaining diesel engines, one common question is: does a 5.9 valve cover fit n a 6.7? This query arises among Cummins enthusiasts, especially those transitioning between the 5.9-liter and 6.7-liter engine models. This article thoroughly explores the compatibility between these valve covers, offering insights, practical advice, and critical considerations for anyone contemplating this swap.
Understanding the Basics: 5.9 vs. 6.7 Valve Covers
Before answering “does a 5.9 valve cover fit n a 6.7? The 5.9 and 6.7 Cummins engines are similar in many ways, but the valve covers are not identical. Both engines are part of the Cummins B-series family, but their designs have evolved.
Key Differences:
- Dimensions and Bolt Patterns: While the overall size of both engines is comparable, the bolt pattern and internal structure differ.
- Crankcase Ventilation: The 6.7 has an integrated crankcase ventilation system, unlike the 5.9, which may affect fitment.
Does a 5.9 Valve Cover fit n a 6.7 Physically?
The short answer to “does a 5.9 valve cover fit n a 6.7” is: not direct. The valve covers from a 5.9-liter engine do not align perfectly with the 6.7-liter head due to differences in design and bolt hole alignment. Although the overall dimensions appear similar, these slight variations prevent a straightforward swap.
Compatibility Issues Explained
To fully address the question, does a 5.9 valve cover fit n a 6.7, let’s dive deeper into the specific compatibility issues:
- Bolt Alignment: The bolt holes on the 5.9 cover do not match the pattern on the 6.7 head. Modifications would be necessary to make them fit.
- Seal Differences: The 6.7 valve cover has a different sealing system, which affects its compatibility with a 5.9 cover.
- Internal Clearance: The internal layout of the 6.7 head is slightly different, potentially causing clearance issues with the 5.9 cover.
Why Would You Want to Swap Valve Covers?
If you’re asking, does a 5.9 valve cover fit n a 6.7, you might be considering a swap for several reasons:
- Aesthetics: Some prefer the look of the older 5.9 valve covers.
- Availability: 5.9 valve covers might be more readily available or cheaper.
- Performance Mods: Certain aftermarket modifications for the 5.9 may not be available for the 6.7.
Alternatives to Direct Swaps
If you’ve determined that the answer to “does a 5.9 valve cover fit n a 6.7” is no, there are alternative solutions:
- Custom Adapters: Fabricating or purchasing an adapter plate can help align the bolt holes.
- Aftermarket Valve Covers: Many companies offer performance valve covers designed specifically for the 6.7.
- Modifying the 5.9 Cover: With machining expertise, modifying a 5.9 cover to fit a 6.7 head is possible, though it may not be cost-effective.
Common Misconceptions
Some believe that since the engines are from the same family, the valve covers are interchangeable. This misunderstanding leads many to ask, does a 5.9 valve cover fit n a 6.7? The truth is, while similar, they are not designed to be swapped without modifications.
Real-World Experiences
Many mechanics and Cummins owners have attempted this swap. Most conclude that the effort involved in making a 5.9 valve cover fit on a 6.7 is significant. Discussions on forums highlight the challenges and often recommend opting for a proper 6.7 cover instead.
Expert Recommendations
Professionals generally advise against swapping a 5.9 valve cover onto a 6.7. They recommend using components designed specifically for each engine. This ensures proper fitment, reduces the risk of leaks, and maintains engine performance.
Cost Considerations
If you’re considering this swap to save money, it’s essential to weigh the costs. Modifying a 5.9 valve cover to fit a 6.7 can be more expensive than purchasing a 6.7-specific cover. This is a necessary factor in the decision-making process.
Does a 5.9 Valve Cover fit n a 6.7 for Performance Gains?
Using a 5.9 valve cover on a 6.7 does not benefit performance. The 6.7 valve cover is optimized for that engine’s specifications.
Conclusion
To summarize, the question does a 5.9 valve cover fit n a 6.7 has a clear answer: No, it does not fit directly. The differences in bolt patterns, internal design, and crankcase ventilation make this swap challenging. While it’s technically possible with modifications, using a valve cover explicitly designed for the 6.7 is often more practical and cost-effective.
FAQs
1. Can I modify a 5.9 valve cover to fit a 6.7?
Yes, but it requires significant modifications and may need to be more cost-effective.
2. Are there aftermarket valve covers for the 6.7 Cummins?
Yes, many aftermarket options offer performance and aesthetic improvements.
3. Why do the bolt patterns align between 5.9 and 6.7 covers?
The 6.7 head has a different design to accommodate its more significant displacement and updated features.
4. Is there any performance gain in swapping covers?
No, using the correct valve cover ensures optimal performance and reduces the risk of issues.
5. Are 5.9 and 6.7 valve covers made from the same material?
They are similar but differ in internal structure and sealing methods.