OE Match

• Porsche 996 C2 3.6L 09/01-2005 (engine code M9603)
• Porsche 996 C4 3.6L 09/01-2005  (engine code M9603)
• Porsche 996 C4S 3.6L 09/01-2005  (engine code M9603)
• Porsche 997 MK1 Carrera 2 3.6L 2005-08  (engine code M9605)
• Porsche 997 MK1 Carrera 2S 3.8L 2005-08  (engine code M9701)
• Porsche 997 MK1 Carrera 4 3.6L 2005-08  (engine code M9605)
• Porsche 997 MK1 Carrera 4S 3.8L 2005-08 (engine code M9701)

Designed to maintain original journal dimensions and deliver balanced, dependable rotation, this crankshaft ensures proper bearing clearances, stable lubrication and smooth power delivery—essential for both everyday driving and spirited performance use.

Whether restoring a high-mileage engine, repairing bottom-end damage or conducting a complete power unit rebuild, this precision crankshaft is fundamental to achieving long-term reliability and authentic Porsche performance.

What the Crankshaft Does

This crankshaft performs multiple key functions at the heart of the Porsche flat-six engine:

• Transforms piston motion into smooth, controlled rotational torque
• Maintains exact journal sizing for correct oil clearance and bearing support
  
• Provides balanced rotation across the engine’s full RPM range
  
• Supports consistent lubrication through precision oil galleries
  
• Ensures durable, stable bottom-end operation under high loads
  
• Forms the structural core of the M96/M97 rotating assembly

A correctly sized, properly balanced crankshaft is essential for engine health, power consistency and long-term performance.

Why Porsche Crankshafts Can Fail

While Porsche’s M96/M97 engines are known for performance, certain conditions can cause premature crankshaft wear or failure. Common causes include:

• Oil starvation leading to bearing knock and journal scoring
  
• High mileage fatigue causing cracks or out-of-round journals
  
• Worn or failed bearings damaging crankshaft surfaces
  
• Contaminated lubrication accelerating wear on critical journals
  
• Overheating compromising crankshaft strength
  
• Imbalance due to previous machining or improper rebuild work
  
• Harmonic vibration intensified by worn flywheel or pulley components

Symptoms often include low oil pressure, knocking noises, metal debris in oil filters, engine vibration or difficulty maintaining consistent RPM.

Why You Should Replace a Worn Crankshaft

Replacing a damaged crankshaft with a precision-built, standard size replacement designed to match Porsche performance characteristics restores the reliability and durability required from the M96/M97 engine.

Key benefits include:

• Restored journal accuracy and correct bearing clearance
• Improved lubrication and oil pressure stability
• Smooth, balanced rotation across all RPM ranges
• Prevention of major bottom-end failures
• Enhanced reliability for road and performance driving
• Extended lifespan of rods, pistons, bearings and related components

For 996 and 997.1 owners, a correct standard-size crankshaft is vital to a successful and lasting engine rebuild.

Standard Size Crankshaft (STD)
The standard size (STD) engine crankshaft is an essential rotating component for the early air-cooled Porsche models.

Fits:

• Porsche 911 1965-1968 2.0L / 912 SWB (F)
• Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
• Porsche 914-6 2.0L (1970-1976)

These first-generation air-cooled flat-six engines rely heavily on the strength, balance and accuracy of the crankshaft to deliver the smooth, free-revving performance that made the classic 911 legendary.

Whether performing a true-to-original restoration or a full bottom-end rebuild, this crankshaft ensures proper bearing clearances, smooth rotation and the reliability required to support both naturally aspirated and early turbocharged Porsche engines.

What the Crankshaft Does

This crankshaft plays a central role in engine operation by:

• Transforming piston movement into rotational torque to drive the transmission
  
• Maintaining exact journal sizing for correct oil film and bearing support
  
• Ensuring balanced rotation across the entire RPM range
  
• Supporting reliable lubrication through precision oil galleries
  
• Handling high load and thermal stress typical of air-cooled performance engines
  
• Providing dependable bottom-end stability for both normally aspirated and turbocharged setups

Without a properly sized and balanced crankshaft, the engine cannot run smoothly or reliably.

Why Crankshafts Can Fail

Although Porsche’s air-cooled crankshafts are renowned for durability, age, performance use and lubrication issues can lead to failure. Common causes include:

• Oil starvation causing bearing damage and journal scoring
  
• Contamination in the oil system leading to abrasive wear
  
• High-mileage fatigue resulting in stress cracks or journal out-of-round conditions
  
• Overheating reducing metallurgical strength
  
• Incorrect machining or imbalance from past rebuilds
  
• Detonation or pre-ignition placing excessive load on journals
  
• Corrosion from long storage or moisture intrusion

Symptoms can include low oil pressure, vibration, bearing noise, metal debris in the oil, or excessive crankshaft end-float.

Why You Should Replace a Worn or Damaged Crankshaft

Installing a new or precision-engineered standard size crankshaft—matched to original Porsche tolerances—provides the foundation for a reliable, long-lasting engine rebuild.

Benefits include:

• Restored bearing clearance and proper lubrication
• Smooth rotational balance and reduced engine vibration
• Improved reliability for both standard and turbocharged engines
• Protection against catastrophic bottom-end failures
• Extended lifespan for connecting rods, bearings and pistons
• Consistent performance in high-heat air-cooled environments

For early air-cooled Porsche models, the crankshaft is one of the most critical components that determines the success and durability of any engine rebuild.

Standard Size Crankshaft (STD)
The standard size (STD) engine crankshaft is an essential rotating component for the early air-cooled Porsche models.

Fits:

• Porsche 911 1972-1973 2.4L / 2.7L RS LWB (F)
• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1975-1977 3.0L Turbo (930)  

Designed to maintain original journal dimensions and deliver long-lasting structural integrity, this crankshaft provides the precision, balance and strength demanded by classic flat-six engines.

Whether performing a true-to-original restoration or a full bottom-end rebuild, this crankshaft ensures proper bearing clearances, smooth rotation and the reliability required to support both naturally aspirated and early turbocharged Porsche engines.

What the Crankshaft Does

This crankshaft plays a central role in engine operation by:

• Transforming piston movement into rotational torque to drive the transmission
  
• Maintaining exact journal sizing for correct oil film and bearing support
  
• Ensuring balanced rotation across the entire RPM range
  
• Supporting reliable lubrication through precision oil galleries
  
• Handling high load and thermal stress typical of air-cooled performance engines
  
• Providing dependable bottom-end stability for both normally aspirated and turbocharged setups

Without a properly sized and balanced crankshaft, the engine cannot run smoothly or reliably.

Why Crankshafts Can Fail

Although Porsche’s air-cooled crankshafts are renowned for durability, age, performance use and lubrication issues can lead to failure. Common causes include:

• Oil starvation causing bearing damage and journal scoring
  
• Contamination in the oil system leading to abrasive wear
  
• High-mileage fatigue resulting in stress cracks or journal out-of-round conditions
  
• Overheating reducing metallurgical strength
  
• Incorrect machining or imbalance from past rebuilds
  
• Detonation or pre-ignition placing excessive load on journals
  
• Corrosion from long storage or moisture intrusion

Symptoms can include low oil pressure, vibration, bearing noise, metal debris in the oil, or excessive crankshaft end-float.

Why You Should Replace a Worn or Damaged Crankshaft

Installing a new or precision-engineered standard size crankshaft—matched to original Porsche tolerances—provides the foundation for a reliable, long-lasting engine rebuild.

Benefits include:

• Restored bearing clearance and proper lubrication
• Smooth rotational balance and reduced engine vibration
• Improved reliability for both standard and turbocharged engines
• Protection against catastrophic bottom-end failures
• Extended lifespan for connecting rods, bearings and pistons
• Consistent performance in high-heat air-cooled environments

For valuable classics like the 1972–77 Porsche 911 and early 930 Turbo, a correct STD crankshaft is essential to preserving performance and longevity.

Crankshaft Standard (STD)
The standard size (STD) crankshaft is a key rotating component for the classic Porsche 911 SC (3.0ltr). 

Fits:

• Porsche 911 1978-1983 3.0L / SC         

Engineered to match original build specifications, this crankshaft ensures proper journal dimensions, smooth rotation and long-term durability within the renowned air-cooled flat-six engine. Whether restoring a classic 911 SC or rebuilding a high-mileage bottom end, this precision-machined crankshaft plays a vital role in maintaining authentic Porsche performance.

Designed to maintain original journal dimensions and deliver exceptional strength, this crankshaft plays a crucial role in preserving the smoothness, reliability and performance expected from these high-value flat-six engines.

Whether performing a classic restoration, a bottom-end refresh or a full performance rebuild, this crankshaft is essential for ensuring correct bearing clearances, optimal lubrication and long-term engine integrity.

What the Engine Crankshaft Does

This crankshaft is responsible for key engine functions, including:

• Converting piston motion into rotational torque that drives the transmission
  
• Maintaining accurate journal diameters to support proper bearing lubrication
  
• Providing smooth, balanced rotation across the engine’s entire RPM range
  
• Distributing oil internally through precision-machined lubrication galleries
  
• Supporting turbocharged loads with a strong, durable crank web and journal design
  
• Forming the foundation of the bottom-end rotating assembly

A correct standard-size crankshaft is vital to the long-term reliability and performance of any air-cooled Porsche flat-six.

Why Crankshafts Can Fail

Even though Porsche engineered these crankshafts for durability, decades of use and performance driving can lead to wear or damage. Common causes of failure include:

• Oil starvation resulting in journal scoring or bearing failure
  
• Metal fatigue from high RPM use, boost pressure or detonation
  
• Contamination in the oil supply causing abrasive wear
  
• Overheating weakening the crankshaft’s molecular structure
  
• Incorrect machining from past rebuilds creating imbalance or mismatched tolerances
  
• Severe knock events bending or cracking the crankshaft
  
• High-mileage wear reducing journal roundness and bearing clearances

Symptoms of crankshaft-related failure include low oil pressure, metallic knocking, vibration, bearing debris in oil, and uneven rotation during teardown.

Why You Should Replace a Damaged or Worn Crankshaft

Installing a new or precision-built standard size crankshaft—designed to match original Porsche performance tolerances—ensures a strong, balanced and reliable engine rebuild.

Key benefits include:

• Restored bearing clearances and stable oil pressure
• Smooth, balanced engine rotation at all RPM ranges
• Reduced vibration and improved power delivery
• Enhanced reliability under turbocharged loads
• Prevention of severe bottom-end failures
• Increased lifespan of pistons, rods and bearings
• Assurance of correct geometry for high-performance use

For a Porsche 911 SC rebuild, choosing the correct STD crankshaft is one of the most important steps in achieving a long-lasting, dependable engine.

Crankshaft Standard (STD)
This standard size crankshaft (STD) is a precision-engineered rotating assembly component used in several iconic Porsche air-cooled engines.

Fits:

• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 911 1984 -1989 3.3L Turbo (930)
• Porsche 964 (911) TURBO 3.3L 1991-93       

Designed to maintain original journal dimensions and deliver exceptional strength, this crankshaft plays a crucial role in preserving the smoothness, reliability and performance expected from these high-value flat-six engines.

Whether performing a classic restoration, a bottom-end refresh or a full performance rebuild, this crankshaft is essential for ensuring correct bearing clearances, optimal lubrication and long-term engine integrity.

What the Engine Crankshaft Does

This crankshaft is responsible for key engine functions, including:

• Converting piston motion into rotational torque that drives the transmission
  
• Maintaining accurate journal diameters to support proper bearing lubrication
  
• Providing smooth, balanced rotation across the engine’s entire RPM range
  
• Distributing oil internally through precision-machined lubrication galleries
  
• Supporting turbocharged loads with a strong, durable crank web and journal design
  
• Forming the foundation of the bottom-end rotating assembly

A correct standard-size crankshaft is vital to the long-term reliability and performance of any air-cooled Porsche flat-six.

Why Crankshafts Can Fail

Even though Porsche engineered these crankshafts for durability, decades of use and performance driving can lead to wear or damage. Common causes of failure include:

• Oil starvation resulting in journal scoring or bearing failure
  
• Metal fatigue from high RPM use, boost pressure or detonation
  
• Contamination in the oil supply causing abrasive wear
  
• Overheating weakening the crankshaft’s molecular structure
  
• Incorrect machining from past rebuilds creating imbalance or mismatched tolerances
  
• Severe knock events bending or cracking the crankshaft
  
• High-mileage wear reducing journal roundness and bearing clearances

Symptoms of crankshaft-related failure include low oil pressure, metallic knocking, vibration, bearing debris in oil, and uneven rotation during teardown.

Why You Should Replace a Damaged or Worn Crankshaft

Installing a new or precision-built standard size crankshaft—designed to match original Porsche performance tolerances—ensures a strong, balanced and reliable engine rebuild.

Key benefits include:

• Restored bearing clearances and stable oil pressure
• Smooth, balanced engine rotation at all RPM ranges
• Reduced vibration and improved power delivery
• Enhanced reliability under turbocharged loads
• Prevention of severe bottom-end failures
• Increased lifespan of pistons, rods and bearings
• Assurance of correct geometry for high-performance use

For high-value Porsche models like the 911 Carrera 3.2 and Turbo variants, a correct, high-quality STD crankshaft is one of the most critical investments in any rebuild.

Crankshaft  Standard (STD)
The standard size crankshafts are key rotating components used in Porsche 993 engines and 996 Turbo models. 

Fits:

• Porsche 993 (911) C2 1994-97
• Porsche 993 (911) C4 1994-97
• Porsche 993 (911) RS 1994-97
• Porsche 993 (911) C2S 1994-97
• Porsche 993 (911) C4S 1994-97
• Porsche 993 (911) TURBO 1994-96
• Porsche 993 (911) GT2 1994-97
• Porsche 993 (911) TURBO S 1994-97
• Porsche 996 TURBO 2000-05
• Porsche 996 GT2 2001-05

Diagram ref no 1

The crankshaft delivers the precise journal dimensions, balance and strength needed for the high-performance flat-six architecture. Designed to maintain original tolerances, a standard-size crankshaft ensures correct bearing clearances, smooth rotation and reliable power delivery—crucial for both road and track-driven Porsches.

For any engine rebuild, restoration or major service involving these models, choosing a correctly machined and precision-balanced standard size crankshaft is essential to restoring authentic performance and long-term reliability.

What These Standard Size Porsche Crankshafts Do

Designed to work at the core of the bottom end assembly, these crankshafts:

• Convert piston movement into rotational torque to power the drivetrain
• Maintain exact journal diameters for correct bearing oil film clearance
• Provide engine balance across all RPM ranges—crucial for high-revving Porsche flat-six engines
• Facilitate internal lubrication via precision oil galleries
• Support smooth, strong and consistent power delivery Ensure structural integrity under boost conditions in 996 turbo engines

These crankshafts are engineered to perform reliably under demanding thermal, mechanical and load environments typical of Porsche performance models.

Why Porsche 993 & 996 turbo Crankshafts Can Fail

Even though Porsche flat-six crankshafts are exceptionally robust, years of use, high RPM and turbocharged forces can lead to failure. Common causes include:

• Oil starvation or low pressure causing severe journal scoring
• Bearing shell failure damaging journals and lubrication paths
• Metal fatigue from aggressive driving, detonation or over-boost scenarios
• Overheating weakening the crankshaft material
• Contamination in oil scoring journals and reducing bearing life
• Imbalance from previous poor machining or unbalanced accessories
• High mileage fatigue affecting torsional stability

Symptoms of failure include persistent vibration, knocking noises, falling oil pressure, bearing debris in oil or visible wear during teardown.

Why You Should Replace a Worn Crankshaft

Replacing a damaged crankshaft with a precision-built standard size alternative engineered to match original performance characteristics is crucial to achieving a reliable and long-lasting Porsche engine rebuild.

Key benefits of replacement include:

• Restored correct bearing clearances for stable oil pressure
• Smoother rotation and reduced engine vibration
• Improved reliability for high-load, high-RPM and turbocharged conditions
• Prevention of catastrophic bottom-end failures
• Extended service life for bearings, rods and pistons
• Enhanced performance consistency and engine smoothness

With Porsche 993 and 996 Turbo engines now highly valued by enthusiasts, a precision crankshaft is foundational to any proper rebuild or restoration.

Standard Size Crankshaft (STD)
The standard size crankshaft (STD) is a critical rotating component used in Porsche 964 engines. 

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93
• Porsche 964 (911) TURBO S 3.6L 1991-93

Precision machined to maintain original journal dimensions, this crankshaft ensures proper bearing clearance, smooth rotation and reliable power delivery. When rebuilding a high-performance flat-six engine, choosing the correct standard size crankshaft is essential to restoring the engine’s structural integrity and achieving long-term durability.

Engineered to meet the performance characteristics of the original design, this crankshaft is ideal for restorations, performance rebuilds and repairs requiring uncompromising accuracy and balance.

What the Engine Crankshaft Does

This crankshaft delivers several vital engine functions, including:

• Converting piston motion into smooth rotational force
• Maintaining precise journal dimensions for correct oil film and bearing clearance
  
• Balancing the rotating assembly to minimise vibration and engine stress
  
• Supporting consistent oil delivery through internal lubrication channels
  
• Ensuring smooth power transfer across all RPM ranges
• Forming the structural core of the bottom end assembly

A well-balanced standard-size crankshaft is essential for proper engine behaviour, especially in performance-prone flat-six units.

Why Crankshafts Commonly Fail

Despite being exceptionally robust, crankshafts can fail due to age, wear or incorrect operating conditions. Common causes include:

• Oil starvation leading to journal scoring or bearing failure
  
• Metal fatigue after years of high-RPM use or detonation events
  
• Overheating compromising the metallurgical integrity of the crankshaft
  
• Contamination from debris causing gouging or premature wear
  
• Imbalance or improper machining from previous engine work
  
• Severe knock or misfires bending or twisting the crankshaft
  
• Prolonged high load driving accelerating fatigue in older engines

Symptoms typically include low oil pressure, knocking noises, excessive vibration, or visible scoring on journals during teardown.

Why You Should Replace a Worn or Damaged Crankshaft

Replacing a compromised crankshaft with a precision-built, standard size alternative engineered to match the original specifications ensures your Porsche 964 rebuild is stable, durable and capable of performing as intended.

Benefits include:

• Restored bearing clearance and oil pressure stability
• Reduced engine vibration and smoother power delivery
• Stronger resistance to high-RPM and high-load conditions
• Improved longevity of other bottom-end components
• Prevention of catastrophic engine damage or seizure
• More accurate balancing for performance and reliability

During an engine rebuild, the crankshaft is one of the most critical components to inspect and replace if any wear is detected.