B48 Cylinder Head Service by 5150 AutoSport

5150 AutoSport Performance Cylinder Head Services for BMW B48 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 performance builds. We offer three levels of service to meet your budget and build goals, from OEM refresh to full race-level machining:

Stage 1 – OEM Refresh (Rebuild & Reliability Focused)

Ideal for stock or mildly modified engines needing a proper refresh.

The cylinder head is fully disassembled, cleaned, and soda blasted to remove carbon and contaminants. Valve guides are measured and inspected, with new guides installed if needed, then precision reamed and honed for proper clearance. A 5-angle valve job is performed to restore sealing efficiency, followed by resurfacing to ensure a flat, true mating surface. New Viton valve seals are installed, the head is fully reassembled using OEM valves, guides, springs, and retainers, and pressure tested after assembly.
Optional service upgrade: add a high-performance valve spring kit.

Stage 1 at a Glance: 

• Disassemble and Clean
• Soda Blast
• Inspect and Measure Valve Guides
  • Removal and Installation of new Guides, if necessary
• Ream and Hone Valve Guides
• 5-Angle Valve Job
• Resurfacing
• Final Wash
• Install New Viton Valve Seals
• Setting of Seat Pressure
• Full Reassembly
• Pressure Testing after assembly

Stage 2 – Performance Valvetrain Upgrade

For higher RPM builds and increased durability.

Includes everything from Stage 1, plus upgraded high-performance valves, a high-performance valve spring kit, and new valve locks/keepers. This stage improves valvetrain stability, reduces the risk of valve float, and prepares the head for more aggressive use while retaining OEM-style machining processes.

Stage 2 at a Glance: 

• Disassemble and Clean
• Soda Blast
  
• Removal of OEM Valve Guides
• Installation of Performance Valve Guides
• Ream and Hone Valve Guides
• 5-Angle Valve Job
• Resurfacing
• Final Wash
• Install New Viton Valve Seals
• Install New High Performance Valve Spring Kit
• Install New High Performance Valve Kit
• Install New High Performance Valve Keepers
• Setting of Seat Pressure
• Full Reassembly
• Pressure Testing after assembly

Pro-Xtreme – All-Out Performance Cylinder Head Service

Designed for high-horsepower, forced-induction, and competition builds.

The cylinder head undergoes complete disassembly, cleaning, and in-depth inspection, including crack, leak, and pressure testing. Factory valve guides are replaced with high-performance guides, then precision reamed and honed for extreme heat and RPM stability. 

CNC multi-angle porting is performed on both intake and exhaust ports to improve airflow consistency across all cylinders. A CNC multi-angle intake valve job and radius exhaust valve job optimize flow into and out of the combustion chamber. Valves are unshrouded to further enhance airflow, and preventative chamfering is applied in critical areas to reduce stress concentrations.

The mating surface is trueness checked, resurfaced, and verified again for perfect sealing. After machining, the head is thoroughly washed and assembled using balanced and blueprint-matched high-performance valves, along with balanced valve springs and retainers for precise valve control and long-term durability.

Pro-Xtreme at a Glance: 

• Disassemble and Clean
• Soda Blast
  
• Removal of OEM Valve Guides
• Installation of Performance Valve Guides
• Ream and Hone Valve Guides
• 5-Axis CNC Intake Porting
• 5-Axis CNC Exhaust Porting
• CNC Combustion Chamber Modification
• 5-Angle CNC Intake Valve Job
• 5-Angle CNC Exhaust Valve Job
  
• Unshrouding of Valves
• Preventative Chamfering in Potential Problem Areas
• Trueness Checking of Mating Surface
• Resurfacing
• Final Wash
• Install New Viton Valve Seals
  
• Install New High Performance Valve Spring Kit
• Install New High Performance Valve Kit
• Install New High Performance Valve Keepers
• Setting of Seat Pressure
• Full Reassembly
• Pressure Testing after Assembly

Read more about our Pro-Xtreme service here. 

BMW B48 Applications:

1 Series

2016-2019    F20    120i / 125i
2019-2023     F40     118i / 120i / 128ti / 135i / M135i
2024-Present     F70     120 / M135i 

2 Series

2014-2021     F22/F23     218i / 220i / 230i
2014-2017     F45     220 / 225i
2021-Present     G42     218i / 220i / 230i
2021-Present     U06     223i
2020-2024     F44     218i / 220i / 228i / M235i
2025-Present     F74     M235

3 Series

2015-2019     F30/F31/F34     320i / 330i / 330e
2018-Present     G20/G21     318i / 320i / 330i / 330e

4 Series

2016-2019    F32/F33/F36    420i / 430i
2020-Present     G22/G23/G26     420i / 430i / 430e

5 Series

2017-Present     G30/G31     520i / 530i / 530e

6 Series

2017-Present     G32     630i

7 Series

2015-2022     G11/G12     730i / 730Li / 740e / 740Le

X1 Series

2015-2022     F48     sDrive18i / sDrive20i / xDrive20i / 25i / xDrive25i / 28i
2022-Present     U11     sDrive18i / xDrive20i / xDrive28i / M35i

X2 Series

2018-2023     F39     sDrive18i / sDrive20i / xDrive20i / 25i / xDrive25i / 28i / M35i
2023-Present     U10     xDrive28i / M35i

X3 Series

2017-2024     G01     sDrive20i / xDrive20i / xDrive30i / xDrive30e
2025-Present     G45     xDrive20e / xDrive30e

X4 Series

2018-Present     G02     xDrive20i / xDrive30i

X5 Series

2018-Present     G05     xDrive25i / sDrive25i

Z Series

2018-Present     G29     Z4 sDrive20i / sDrive30i

Toyota B48 Applications:

A90 / A91 Supra

2019-Present     J29/DB82/DB22 Supra
2020-Present     GR Supra 2.0  

MINI B48 Applications:

MINI Hatch [F55/F56/F57]

2014-Present     Cooper S
2015-Present     John Cooper Works (JCW)

MINI Clubman [F54]

2015-Present     Cooper S
2016-Present     John Cooper Works (JCW)

MINI Convertible [F57]

2016-Present     Cooper S
2016-Present     John Cooper Works (JCW)