Crank Hub 4-Pin S55 Engine

A common issue with tuned S55 engines is crank hub failure, which can lead to severe engine damage. The VAC Motorsport 4-Pin Crank Hub is engineered to resolve this problem. This hub is CNC machined for greater precision than OEM, featuring a 4-pin design that mechanically locks it to the crank nose. This system prevents the valve timing and oil pump chains from rotating independently of the crankshaft. The assembly process has been simplified from three components to two. As long as the crankshaft bolt is correctly torqued, the timing sprocket will remain perfectly synchronized with the crank. This ensures reliable engine operation, especially under high-boost conditions. The kit includes the crank hub, a keyed oil pump gear, a genuine BMW crankshaft bolt, a drill bit, a drill guide, and a VAC Crank Seal Guard.