N55 Cylinder Head Service by 5150 AutoSport

5150 AutoSport Performance Cylinder Head Services for BMW N55 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 N55 Applications: 1 Series 2010-2013 E82/E88 135i2012-2016 F20/F21 M135i 2 Series 2014-2016 F22/F23 M235i2016-2018 F87 M2 3 Series 2010-2015 E90/E91/E92/E93 335i2012-2015 F30/F31/F34 335i2015-2016 F30/F31 340i 4 Series 2013-2016 F32/F33/F36 435i2016 F32/F33/F36 440i 5 Series 2010-2016 F10/F11 535i2010-2017 F07 535i GT 6 Series 2011-2018 F12/F13/F06 640i Gran Coupe 7 Series 2012-2015 F01/F02 740i / 740Li X1 Series 2013-2015 E84 X1 xDrive35i X3 Series 2011-2017 F25 X3 xDrive35i X4 Series 2014-2017 F26 X4 xDrive35i2016-2017 F26 X4 M40i X5 Series 2011-2018 E70/F15 X5 xDrive35i X6 Series 2011-2019 E71/F16 X6 xDrive35i ALPINA N55 Applications: B3 Series 2013-2018 F30/F31 B3 Bi-Turbo B4 Series 2014-2019 F32/F33 B4 Bi-Turbo