N20 / N26 Cylinder Head Service by 5150 AutoSport

5150 Autosport Pro-Xtreme Cylinder Head Service for BMW N20 and N26 Engines

Please note that price is based on customer providing core. If you need help sourcing a core, please contact our sales team.

Investing in a performance cylinder head service is crucial for optimizing engine potential in high-performance builds. The 5150 Pro-Xtreme Cylinder Head Service includes porting for improved airflow, installing high-performance valve guides, springs, and retainers for precise valvetrain control, and trueness checking with resurfacing to ensure a perfect seal. These enhancements lead to better combustion, increased power output, improved throttle response, and enhanced engine reliability, making it a worthwhile investment for achieving peak performance in high-performance engines.

We only use CNC equipment, ensuring that each valve seat is machined to the exact same specifications, providing uniformity across all cylinders. This precision is crucial for maintaining consistent performance and efficiency.

The result is a completely assembled, high performance cylinder head, including new valves, valve springs, valve seats, and valve guides, ready for re-installation and timing by an experienced engine builder.

Service Includes:

Total Disassembly, Cleaning, & Inspection

Our skilled technicians carefully disassemble and inspect each component for any damage, unusual wear, cracking, warping, etc. and perform leak, crack, and pressure testing to ensure the cylinder head is a good candidate for modifications.

During the cleaning process, techs are able to remove all built up contaminants, such as carbon deposits and oil sludge. Properly cleaned and prepared services are essential to ensure precise port and polish modifications, and establish a baseline for implementing performance modifications accurately.

Performance Valve Guides

Factory Valve Guides are removed and replaced with upgraded high performance valve guides. The new guides are reamed and honed, ensuring proper clearance. Performance valve guides equip the cylinder head for the high temperatures of increased engine temperatures and pressures. Manufactured for a more precise fit between the valve stem and valve guide than OEM valve guides, this maintains optimal alignment and reduces the risk of valve float at high RPMs.

Multi-Angle CNC Porting

Porting involves modifying the intake and exhaust ports of the cylinder head to improve the flow of air and fuel into the combustion chamber and the expulsion of exhaust gases out of the chamber.

The first step of this process involves assessing the cylinder head's current flow characteristics to identify any restrictions or turbulence. Then, material is carefully removed from the walls of the intake and exhaust ports to simultaneously enlarge them and improve their shape for optimal flow. The result is a smoother, more direct path for air and fuel into the combustion chamber, as well as a smooth, more efficient path for exhaust to flow out of the combustion chamber. 

Because we use CNC machining, we can ensure each port is exact and even across the cylinder head. This means airflow is balanced across all cylinders. Benefits of porting include increased airflow for more power and improved throttle response. 

Multi-Angle CNC Intake & Exhaust Valve Job

The goal of a multi-angle intake valve job is to create a more efficient pathway for the air-fuel mixture entering the combustion chamber. By using multiple angles on the valve seat, the transition of airflow is smoothed, which enhances volumetric efficiency.

A radius exhaust valve job focuses on the exhaust side, aiming to optimize the flow of exhaust gases out of the combustion chamber. Instead of using multiple distinct angles, a smooth radius is used to create a seamless transition for the gases, reducing turbulence and backpressure.

Valve Seat Machining: Precision CNC machining shapes the valve seat into a smooth radius, rather than distinct angles.

On the intake side, multiple consistent and precise angles smooth the valve seat for the even transition of airflow and greater volumetric efficiency.

On the exhaust side, this smooth curve assists in minimizing resistance to improve the flow of exhaust gasses. As exhaust flows out of the combustion chamber more efficiently, overall engine performance improves.

Unshrouding of Valves

A part of the port and polish process, unshrouding valves is a modification technique used to enhance airflow around the valves. This process involves removing material from the cylinder head around the valve seats and edges of the combustion chamber. This creates more space around the valves when they are open, creating better airflow into and out of the combustion chamber.

Preventative Chamfering in Potential Problem Areas

Chamfering involves creating a beveled edge at the intersection of two surfaces, typically the edges of ports, valve seats, and other openings. In addition to the benefits of improved flow, this technique is used at the edges of ports to reduce stress concentrations, which might otherwise lead to cracks or other damages over time. Additionally, properly chamfered valve seats can enhance sealing for greater compression and combustion efficiency. 

Trueness Checking of Mating Surface and Resurfacing

The cylinder head is measured to ensure perfect, uniform flatness and freedom from warping or irregularities. A flat mating surface is essential for proper sealing, and any warping or unevenness can lead to gasket failure, resulting in leaks and compromised performance. 

After initial trueness checking, the cylinder head is resurfaced to restore flatness and ensure a perfect seal with the engine block and head gasket. This machining process removes any warping, pitting, or damage, creating a perfectly flat surface. The cylinder head is then once again trueness checked to ensure optimal sealing and lasting performance. 

Wash & Final Assembly 

Following machining, a thorough wash is to remove any metal shavings or contaminants from the machining process, preparing the cylinder head for final assembly:

Balanced and Blueprinted One-Piece High-Performance Valves

Durable, high-performance valves are carefully weight-matched and balanced for optimal engine operation. Even valve weights mean reduced vibration for smooth engine operation and reduced component wear. 

Blueprinting refers to the process of assembling the cylinder head to exact specifications, depending on the application and intended usage. Because our specifications exceed factory, this means every single component is carefully measure and machined to ensure it meets our standards. This involves meticulous attention to detail, ensuring every piece fits perfectly and operates at their best.

Balanced High-Performance Valve Springs and Retainers

To ensure lasting durability, reliability, and efficiency, balanced and weight-matched valve springs replace OEM springs for better valve control and timing. Responsible for keeping valves closed during compression and power strokes, uprated valve springs prevent valve float and provide precise control over the opening of valves for optimal valve timing.

Working in conjunction with valve springs, retainers are also responsible for reliable and efficient valvetrain operation. Performance retainers boast superior strength and rigidity, resisting deformation even under extreme engine conditions. 

BMW N20 Applications:

1 Series

2011-2015     F20/F21     116i / 118i / 120i / 125i

2 Series

2014-2016     F22/F23     220i / 228i

3 Series

2012-2016     F30/F31     320i / 328i
2013-2016     F34     320i / 328i GT

4 Series

2013-2016     F32/F33     420i / 428i

5 Series

2011-2017     F10/F11     520i / 528i
2011-2017     F07     520i / 528i GT

X1 Series

2012-2017     E84     X1 sDrive20i / xDrive20i / xDrive28i

X3 Series

2012-2017     F25     X3 sDrive20i / xDrive20i / xDrive28i

X4 Series

2014-2016     F26     X4 xDrive20i / xDrive28i

X5 Series

2013-2014     F15     X5 xDrive25i / xDrive28i

Z Series

2011-2016     E89     Z4 sDrive20i / sDrive28i

BMW N26 Applications:

3 Series

2013-2016     F30/F31     320i / 328i / 328i xDrive
2014-2016     F34     328i / 328i xDrive GT

4 Series

2014-2016     F32/F33     428i / 428i xDrive
2014-2016     F36     428i / 428i xDrive Gran Coupe

5 Series

2012-2016     F10     528i / 528i xDrive

X1 Series

2013-2015     E84     X1 xDrive28i

X3 Series

2013-2017     F25     X3 xDrive28i