EM Performance Aluminum Upper Timing Cover For EA888.3 EM-OE-001

The MMR Performance One-Piece Crank Hub Fix is engineered to fully resolve the well-known crank hub issue found on BMW S55 and N55 engines. The factory three-piece crank hub relies on friction plates that can slip under load, causing engine timing to shift and potentially leading to severe engine damage.

MMR’s upgraded solution replaces the original multi-piece unit with a single-piece billet EN36 steel crank hub, heat-treated with case hardening for exceptional strength and durability. The one-piece design eliminates the possibility of friction plate slippage, significantly improving engine reliability even on tuned or high-power vehicles.

The kit can also be paired with an optional Capture Plate, which locks over the crank bolt head to prevent loosening from vibration, providing complete peace of mind for both standard and modified engines.

For most stock to Stage 1 tuned engines, the non-pinned version provides sufficient reliability, while high-power builds may benefit from the pinned version for maximum engine security.

• CNC-Machined 7075 Aluminum Billet Cover
• UKS JANNE VICOSE Shaft Seal-Made in JAPAN
• 304 Stainless Steel Bolts

The MMR 4-Pinned Single-Piece Crank Hub kit is a high-strength performance upgrade for BMW S55 and N55 engines designed to completely eliminate a known failure point in the factory crank hub. The standard multi-piece crank hub on these engines is prone to slipping under high boost or torque, which can cause the engine’s timing to change and lead to piston-to-valve contact — resulting in extremely costly engine damage.

This upgraded crank hub is machined from billet EN36 steel with case-hardening, making it significantly stronger and more durable than the OEM unit. It features four aerospace-precision dowels that mechanically lock the hub to the end of the crankshaft, preventing any rotational slippage. The kit also includes a full installation jig with drilling guide and high-speed drill bit to assist professional fitting.

For even greater security, an optional capture plate can be included to prevent the crank bolt from loosening under vibration. This combination provides a robust reliability upgrade for high-power engines and helps protect against catastrophic crank hub failure.