This N55 / S55 crankshaft hub does not require the oil pan to be removed* nor does it require any holes to be drilled into the crankshaft. Installation is as simple as turning a bolt**. This kit includes a new crankshaft hub and the bolt capture plate to be used with a new factory crankshaft bolt.
Video: Vargas Spline Lock Solution for BMW S55 Crank Hub
This hub has precisely-machined splines on the inner tip. As the hub is pushed into the crankshaft (pressed in by the bolt), the splines dig into the steel crankshaft snout. The shape and size of the splines has been developed and tested through many engineering hours to secure the hub into the crankshaft and avoid the dreaded spun crank hub, even on cars tuned beyond 900hp. Other solutions like a pinned crank hub require holes to be drilled into the crank for the pins. We like this method too but if you - or your mechanic - are squeamish about drilling this is also a proven solution.
Included is the Vargas Crank Bolt Capture that further ensures the bolt will not loosen and allow the hub to spin. The Capture plate is machined to match the hex of the large factory crankshaft bolt and uses the 8 bolts from the vibration damper to stop the main crank bolt from coming loose. The splined hub must only be used with this Capture plate.
Also included is a spline hub puller in case you need to remove the splined hub in the future. The splines grip the crankshaft so tightly that this special puller is required.
A new factory crankshaft bolt (BMW part #11217573672) is required and sold separately. See Related Items below. Use only a factory crankshaft bolt - not aftermarket or upgraded.
* oil pan should be removed if the original hub has spun and obviously needs to be removed if replacing rod bearings or other bottom-end work.
** factory bolt is a stretch bolt. We say “easy as turning a bolt” but this bolt requires 100 Nm (74ft-lbs) plus 270° rotation to stretch the bolt. This is not as high as other crank bolts but cannot be done without locking the engine in place and care must be used to not jump timing or damage other timing.
