Failures caused by the standard three-piece crank hub on BMW’s S55 & N55 engines in M2C, M3 and M4, and M135i & M235i are (unfortunately) all-too well known, but these are fully addressed with the installation of the ultimate MMR Performance 4-Pin Single-Piece billet Crank Hub, together with the option of adding our Capture Plate for ultimate security.
MMR Performance now offers an uprated version of the popular Single-Piece Crank Hub, with this 4-Pin dowelled version that locks onto the end of the crankshaft.
The OE crank hub unit's friction plate are known to slip rotationally, causing the timing to alter enough that piston-to-valve contact can occur, leaving owners with a very expensive repair bill.
For high horsepower & torque engines, this 4-pin version of MMR's Single-Piece Crank Hub kit is simply the ultimate solution to preventing this problem before it happens.
The centrepiece of the MMR kit is the UK-made CNC-machined one-piece crank hub, created from billet EN36 steel that's been heat-treated with a 0.75mm case hardening, making it incredibly strong and durable. Along with this comes four aerospace precision machined dowels that mechanically lock the hub to end of the crank itself, plus a brand new OE bolt.
Together, the Single-Piece design combined with the 4-Pin location ensures that there is now no way that crank hub can ever slip. With the new OE crank bolt tightened appropriately, this delivers a transformational improvement in reliability versus the OE version.
For BMW M2C, M3 and M4 S55-engined cars running high power and torque outputs, plus N55-powered M2, M135i, M235i, 335i & 435i cars, MMR have engineered the most comprehensive solution on the market and at one of the most compelling price points. Don't run high power without one!
*Installation of this kit is certainly not a DIY job. But to make the job easier for the professionals, ensuring that the required crank modifications are made safely and accurately, the MMR kit also includes a full installation jig that includes a bolt-on drilling guide, a location bolt for this guide, plus an HSS rolled high speed Drill Bit.
Finally, alongside the 4-Pinned Crank Hub, the optional MMR Capture Plate ensures that owners have complete peace of mind. The Capture Plate removes the possibility for the crank bolt to be able to loosen with the engine's vibrations or harmonics. The Capture Plate is an additional billet aluminium hat that securely bolts over the entire head of the crank bolt, making it literally impossible for the bolt to come undone.