Crankshaft bearing STANDARD. Porsche Boxster 987/ Cayman 987C / 997 M97.21 M97.22 / 996 3.6L M96.03

Crankshaft bearing STANDARD size.
A complete set of crankshaft main bearings - these are the half-shells (upper and lower) that support the crankshaft main journals inside the engine block. The set replaces all main-bearing shells to renew the engine bottom end’s bearing surfaces.
SET OF 14 Bearing Shells

Fits:
Engine code: M96.03
Porsche 996 3.6L

Engine code: M97.21 / M97.22
Porsche 987 Cayman
Porsche 987 Boxster
Porsche 997 3.6L / 3.8L

Diagram Ref No 13.

Sold as a full set of 14 bearing shells - enough to rebuild the entire main bearing bank of a six-cylinder boxer engine.

When installed, this bearing set:
• Provides a precise, low-friction journal surface for the crankshaft to rotate on
• Maintains correct bearing clearance and oil film under high loads and RPMs, ensuring smooth rotation and reducing wear.
• Helps preserve oil pressure and lubrication flow, preventing oil starvation and bearing damage.
• Restores engine reliability and reduces risk of bearing knock, wear or failure, especially on re-built or high-mileage engines.

Over time and use, main bearings wear down - surfaces can score, bearings can become pitted, clearance can increase, oil film may degrade, leading to:
• Engine knocks or bearing rumble
• Loss of oil pressure
• Excess crankshaft play or vibration
• Accelerated wear of crank pins, journals and engine internals

Replacing main bearings with a fresh set restores factory-correct clearances and bearing surfaces, ensuring smooth crankshaft rotation, proper oil flow, and long engine life - especially important after high mileage, rebuilding, or performance modification.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99610120904

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