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BMW Internal Engine Parts

Rebuilding your engine or giving your cylinder head an overhaul? Internal engine components covers parts that are located within the engine block and cylinder head. Examples include: timing chains and tensioners, rocker arms, rod bolts and studs, head bolts, valve springs, connecting rods, and more. These are Genuine BMW engine parts, performance upgrades, or approved aftermarket brands that have a long track record of reliability and quality.

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MMX Crank Hub Capture Plate - Black - S55

T#:4552069

Part#: MMR20-1002

In Stock

$ 187.99 USD

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$ 187.99 USD

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Anyone with a modified S55 knows the risks involved with the OEM Crank Hub. When the engine simply can't handle the stresses its put under or the design is such that it simply does not support extreme conditions, issues can arise. Under certain conditions, the S55 crank hub likes to spin, without warning and even when the engine is in perfect health. MMR has produced a T-6061 machined billet aluminum capture plate anodized in their trademark finish. The MMR Performance capture plate secures the head of the OE crank bolt and prevents it from turning or being able to loosen. This capture plate can be secured to the OEM crank bolt or to MMR's redesigned one-piece crank hub. *Installation recommended by a professional shop or technician.

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MMR One-Piece Crank Hub - S55

T#:4565823

Part#: MMR20-1001

Ships in 1 Business Day

$ 730.99 USD

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$ 730.99 USD

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Anyone with a modified S55 knows the risks involved with the OEM Crank Hub. When the engine simply can't handle the stresses its put under or the design is such that it simply does not support extreme conditions, issues can arise. Under certain conditions, the S55 crank hub likes to spin, without warning and even when the engine is in perfect health. MMX has produced a EN36 machined billet one-piece crank hub heat treated with a 0.75mm case hardening which makes it extremely durable. Due to the one-piece design, it ensures that the friction plates cannot slip. This offers a huge jump in reliability when paired with a new properly torques crank bolt. Installation is requires no drilling or modification to the OEM crankshaft ensuring a perfect fit! Can also be paired with MMR's Performance Capture Plate to ensure against loosening of the crank bolt. *Installation recommended by a professional shop or technician.

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MMX Performance - 4-Pin One-Piece Crank Hub Upgrade Kit - With MMR Ca...

T#:45039725

Part#: MMR20-1004FK

Ships in 3 Business Days

$ 1,227.99 USD

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$ 1,227.99 USD

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The centerpiece of this MMX kit is the UK-made CNC-machined one-piece crank hub, created from billet EN36 steel that's heat-treated with a 0.75mm case hardening, making it incredibly strong and durable. Included are four aerospace precision-machined dowels that mechanically lock the hub to the end of the crank itself, plus a brand new OE bolt. Installation of these dowels 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 MMX 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. Together, the single-piece design combined with the four-pin location ensures that there is simply no way that the friction plates can ever slip. With the new OE crank bolt tightened appropriately, this delivers a transformational improvement in reliability and peace of mind versus the OE version. Also included is the MMR Crank Bolt Capture Plate. This adds one additional layer of defense, preventing the crank bolt from being able to back out and loosen over time, ensuring everything is tightly held together as intended.

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MMR Crank Hub Kit - N55/S55

T#:4565824

Part#: MMR20-1003FK

Ships in 1 Business Day

$ 849.99

This product was last offered at the strikethrough price on
07-14-2026

$ 849.65 USD

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$ 849.65 USD

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Anyone with a modified N55/S55 knows the risks involved with the OEM Crank Hub. When the engine simply can't handle the stresses its put under or the design is such that it simply does not support extreme conditions, issues can arise. Under certain conditions, the N55/S55 crank hub likes to spin, without warning and even when the engine is in perfect health. MMR has produced a EN36 machined billet one-piece crank hub heat treated with a 0.75mm case hardening which makes it extremely durable. Due to the one-piece design, it ensures that the friction plates cannot slip. This offers a huge jump in reliability when paired with a new properly torques crank bolt. Installation is requires no drilling or modification to the OEM crankshaft ensuring a perfect fit! Included in this kit is MMR's T-6061 machined billet aluminum capture plate anodized in their trademark finish. The MMR Performance capture plate secures the head of the OE crank bolt and prevents it from turning or being able to loosen. *Installation recommended by a professional shop or technician.

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S55 / N55 One-Piece Crank Hub Upgrade Kit - 4-Pin

T#:19891361

Part#: MMR20-1004

Special Order: No Guaranteed ETA

$ 1,064.99 USD

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$ 1,064.99 USD

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Both the N55 and S55 engines are plagued by the same issue when chasing high horsepower numbers... the dreaded crankhub failure. Fortunately MMR Performance has released an upgraded version of their already stout single-piece crankhub, but this time offering a 4-pin dowelled location that locks onto the front of the crankshaft. This configuration eliminates the multi-piece crankhub with friction discs in favor of a more robust single piece crankhub. Recommended for high-powered cars over 700 Horsepower

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