4-Pin One-Piece Crank Hub Upgrade Kit, N55 S55 3.0L

The MMX Performance 4-Pin One-Piece Crank Hub Upgrade Kit is a robust solution engineered to address the known failure of the factory three-piece crank hub in BMW N55 and S55 3.0L engines. By replacing the stock unit with a CNC-machined, heat-treated billet EN36 steel hub, this kit eliminates the risk of rotational friction plate slip, which can otherwise lead to catastrophic piston-to-valve contact and costly engine repairs. This upgrade features four aerospace precision-machined dowels that mechanically secure the hub to the crankshaft. The kit includes a comprehensive installation jig with a bolt-on drilling guide, a location bolt, and an HSS rolled high-speed drill bit to ensure accurate crank modifications. Please note that this is a professional-level installation and is not intended for DIY procedures. It also requires specific attention to torque settings: 100Nm initial torque plus 270 degrees. Included with this kit is the MMR Crank Bolt Capture Plate, which provides an essential secondary layer of defense by preventing the crank bolt from loosening due to engine vibrations or harmonics. This component acts as a billet aluminum hat that securely bolts over the head of the crank bolt, rendering it impossible for the fastener to back out during operation.