BMW N54 and N55 Closed Decking Service

Our Closed Decking Service for BMW N54 and N55 engines provides essential reinforcement to address a common vulnerability in these high-performance engines: cylinder wall flex and cracking under high loads.

What is Closed Decking?

Closed decking is a machining process where the top plane of the engine case (the head plane of the case) is modified to accept CNC-machined inserts. This process strengthens the cylinder walls at their weakest point—at the top where combustion occurs—by completely supporting them. This reinforcement is crucial for maintaining engine integrity under high boost and power conditions.

Key Features of Our Service:

• Full Cylinder Wall Support: By machining precise inserts into the engine case, we provide complete support to the cylinder walls, ensuring they remain stable and crack-free under extreme pressure.
• Maintained Cooling Efficiency: All coolant passages in the head gasket are carefully machined into the supporting inserts, preserving the engine's cooling efficiency. Additionally, extra cooling passages can be machined to enhance coolant flow under the head gasket, further improving temperature management.
• Gap Filling for Air-Gapped Cylinders: For N54 and N55 engines with air gaps between cylinders, we fill these gaps with aluminum sheets. This approach offers similar benefits to closed decking by preventing cylinder wall flex and ensuring uniform support across the block.

Benefits:

• Enhanced Durability: Closed decking significantly reduces the risk of cylinder wall cracking, a common failure point in N54 and N55 engines when subjected to high-performance demands.
• Optimized Performance: By maintaining the structural integrity of the engine under high loads, closed decking helps you achieve higher horsepower levels with greater reliability.
• Versatile Application: This service is suitable for both street and race applications, ensuring your BMW engine can handle increased power output without compromising longevity.

Additional Services:

This service can be paired with other offerings such as Line Boring to correct main bearing housing alignment, providing a comprehensive solution for building a robust, high-performance engine.

We can arrange for the pickup and re-delivery of your engine case after all chosen engineering processes are completed. The engine case will be ready for you to start the assembly process, or you can trust it to our professional engine builder.

Contact us today to discuss your exact requirements and ensure your BMW engine is prepared for peak performance.