M40 / M42 / M43 / M44 CNC Cylinder Head Service by 5150 AutoSport

5150 Autosport Pro-Xtreme Cylinder Head Service for BMW M40 / M42 / M43 / M44 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 M40 Applications:

3 Series

1987-1994     E30     316i / 318i
1991-1993     E36     316i / 318i / 318is

5 Series

1988-1992     E34     518i

BMW M42 Applications:

3 Series

1989-1991     E30     318i / 318is
1992-1996     E36     318i / 318is

BMW M43 Applications:

3 Series

1993-1998     E36     316i / 318i / 318is
1998-2001     E46     316i / 318i

5 Series

1994-1996     E34     518i
1995-2000     E39     518i

Z Series

1995-1999     E36/7     Z3 1.8i
1999-2000     E36/7     Z3 1.9i

BMW M44 Applications:

3 Series

1996-1999     E36     318i / 318is

Z Series

1996-1999     E36/7     Z3 1.9i