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Porsche // 944 (1982-1991) // 944 Turbo S 2.5L 8V 1988
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Crankshaft Main Bearing O-Ring, 51x 4.5. Porsche 911 78-89 / 964 / 993 / 996 Turbo / 997 Turbo / GT3 - 99970728541
99970728541/1
Vehicle Group
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1978-1989 3.3L Turbo (930)
- 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 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- 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 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT3 / GT3 RS 2007-09
- Porsche 997 MKII GT3 / GT3 RS 2010-11
- Porsche 997 MKII Turbo 2010-13
Information
Crankshaft Main Bearing O-Ring, 51x 4.5
This OE Match crankshaft main bearing O-ring is a replacement sealing ring for Porsche 911 1978–1989, 964, 993, 996 Turbo, 997 Turbo, and GT3 models. Measuring 51 x 4.5, it is designed to match the original-style fitment and sealing function within the crankshaft / main bearing area.
Sold individually
Fits:
Porsche 911 1978 - 1989
Porsche 964 1989 - 1994
Porsche 993 1995 - 1998
Porsche 996 Turbo 3.6L 2001 - 2005
Porsche 996 GT3 3.6L 1999 - 2005
Porsche 997.1 Turbo 3.6L 2007 - 2009
Porsche 997.2 Turbo 3.6L 2010 - 2013
Porsche 997 GT3 3.6L / 3.8L / 4.0L 2007 - 2011
Diagram ref no 21
The crankshaft main bearing O-ring helps seal the relevant bearing or housing connection to prevent oil leakage and maintain correct engine oil sealing. A properly sealing O-ring is essential for protecting engine components and maintaining oil system integrity.
What This Part Does / Functions
• Replaces the crankshaft main bearing
• O-ring Helps seal the crankshaft / main bearing housing area
• Supports correct engine oil sealing
• Helps prevent oil leaks from aged or flattened seals
• Suitable for engine rebuild, crankshaft, or bearing service
• Replaces hardened, cracked, flattened, swollen, or damaged O-rings
• OE Match replacement for Porsche engine sealing repair.
Why Replace This Part?
O-rings can harden, flatten, crack, swell, or lose sealing ability due to heat, age, oil exposure, pressure, and engine service work. A worn or damaged crankshaft main bearing O-ring may allow oil seepage or leakage, affecting engine cleanliness and oil system reliability. Replacement is recommended whenever the related engine components are removed or when oil leakage is present.
When to Replace This Part
• Engine rebuild or major engine service is being carried out
• Crankshaft or main bearing components are being serviced
• Oil leakage is present around the related sealing area
• The original O-ring is hardened, flattened, cracked, or damaged
• Bearing housing or crankshaft sealing components have been removed
• Preventative replacement is required during engine assembly
• The vehicle is undergoing Porsche engine restoration
Where it fits on the car
This O-ring fits within the engine crankshaft / main bearing sealing area. Exact position can vary depending on engine type and model-specific crankcase layout.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99970728541
The product you are viewing cross references to these numbers
This OE Match crankshaft main bearing O-ring is a replacement sealing ring for Porsche 911 1978–1989, 964, 993, 996 Turbo, 997 Turbo, and GT3 models. Measuring 51 x 4.5, it is designed to match the original-style fitment and sealing function within the crankshaft / main bearing area.
Sold individually
Fits:
Porsche 911 1978 - 1989
Porsche 964 1989 - 1994
Porsche 993 1995 - 1998
Porsche 996 Turbo 3.6L 2001 - 2005
Porsche 996 GT3 3.6L 1999 - 2005
Porsche 997.1 Turbo 3.6L 2007 - 2009
Porsche 997.2 Turbo 3.6L 2010 - 2013
Porsche 997 GT3 3.6L / 3.8L / 4.0L 2007 - 2011
Diagram ref no 21
The crankshaft main bearing O-ring helps seal the relevant bearing or housing connection to prevent oil leakage and maintain correct engine oil sealing. A properly sealing O-ring is essential for protecting engine components and maintaining oil system integrity.
What This Part Does / Functions
• Replaces the crankshaft main bearing
• O-ring Helps seal the crankshaft / main bearing housing area
• Supports correct engine oil sealing
• Helps prevent oil leaks from aged or flattened seals
• Suitable for engine rebuild, crankshaft, or bearing service
• Replaces hardened, cracked, flattened, swollen, or damaged O-rings
• OE Match replacement for Porsche engine sealing repair.
Why Replace This Part?
O-rings can harden, flatten, crack, swell, or lose sealing ability due to heat, age, oil exposure, pressure, and engine service work. A worn or damaged crankshaft main bearing O-ring may allow oil seepage or leakage, affecting engine cleanliness and oil system reliability. Replacement is recommended whenever the related engine components are removed or when oil leakage is present.
When to Replace This Part
• Engine rebuild or major engine service is being carried out
• Crankshaft or main bearing components are being serviced
• Oil leakage is present around the related sealing area
• The original O-ring is hardened, flattened, cracked, or damaged
• Bearing housing or crankshaft sealing components have been removed
• Preventative replacement is required during engine assembly
• The vehicle is undergoing Porsche engine restoration
Where it fits on the car
This O-ring fits within the engine crankshaft / main bearing sealing area. Exact position can vary depending on engine type and model-specific crankcase layout.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99970728541
99970146740
99970728540
99970728541
The product you are viewing cross references to these numbers
Price: £5.50
In stock
Related products
Vehicle Group
- Porsche Boxster 987 MKII 2.9L 2009-12
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche Boxster 981 2.7L 2012-16
- Porsche Boxster 981 S / GTS 3.4L 2012-16
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- 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 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- 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
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT3 / GT3 RS 2007-09
- Porsche 997 MK1 GT2 2007-09
- Porsche 997 MKII GT3 / GT3 RS 2010-11
- Porsche 997 MKII Turbo 2010-13
- Porsche 997 MKII GT2 RS 2011-13
- Porsche 991.1 Carrera C2 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C2S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Carrera C4 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C4S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
- Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
- Porsche 991.1 GT3 3.8L (475 Bhp) 2014-16
- Porsche Cayman 2.9L 987C MKII 2009-12
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
- Porsche Cayman 2.7L 981 2013-16
- Porsche Cayman S / GTS 3.4L 981 2013-16
- Porsche 924S 2.5L 1986-87
- Porsche 924S 2.5L 1988
- Porsche 944 2.5L 8V 1982-87
- Porsche 944 2.7L 8V 1988-89
- Porsche 944S 2.5L 16V 1987-88
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
- Porsche 968 3.0L 1992-94
- Porsche 968 Sport 3.0L 1994-95
- Porsche 968 CS 3.0L 1993-95
- Porsche 968 Turbo S 3.0L 1993-94
Information
Crankshaft Tension Sleeve
Fits:
Porsche 911 Carrera 3.2L 1984-89
Porsche 924S 1986-88
Porsche 944 1982-91
Porsche 968 1992-95
Porsche 964 1989-94
Porsche 993 1994-98
Porsche 996 Turbo / GT2 / GT3 1999-05
Porsche 997 Carrera 2009-12
Porsche 997 Turbo / GT2 2007-09
Porsche 997 Turbo / GT2 RS 2009-14
Porsche 997 GT3 2007-13
Porsche 981 Boxster 2013>>
Porsche 987 Boxster 2009-12
Porsche 981C Cayman 2014>>
Porsche 987C Cayman 2009-13
Porsche 991 Carrera / 991 Turbo / 991 GT3
Diagram ref no 1A
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
PAF013334
The product you are viewing cross references to these numbers
Fits:
Porsche 911 Carrera 3.2L 1984-89
Porsche 924S 1986-88
Porsche 944 1982-91
Porsche 968 1992-95
Porsche 964 1989-94
Porsche 993 1994-98
Porsche 996 Turbo / GT2 / GT3 1999-05
Porsche 997 Carrera 2009-12
Porsche 997 Turbo / GT2 2007-09
Porsche 997 Turbo / GT2 RS 2009-14
Porsche 997 GT3 2007-13
Porsche 981 Boxster 2013>>
Porsche 987 Boxster 2009-12
Porsche 981C Cayman 2014>>
Porsche 987C Cayman 2009-13
Porsche 991 Carrera / 991 Turbo / 991 GT3
Diagram ref no 1A
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
PAF013334
90009503100
PAF013334
The product you are viewing cross references to these numbers
Price: £3.13
In stock
Vehicle Group
- Porsche 924S 2.5L 1986-87
- Porsche 924S 2.5L 1988
- Porsche 944 2.5L 8V 1982-87
- Porsche 944 2.7L 8V 1988-89
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
- Porsche 968 3.0L 1992-94
- Porsche 968 Sport 3.0L 1994-95
- Porsche 968 CS 3.0L 1993-95
- Porsche 968 Turbo S 3.0L 1993-94
Information
Crankshaft pulley.
Fits:
Porsche 924S 1986-88
Porsche 944 / 944 Turbo / 944 Turbo S 1985-89 (for cars with engine: 4405 / 4406 / 4407 / 4408 / 4409 / 4410 / 4411 / 4412 / 4451 / 4452)
Porsche 968 1992-95
Diagram ref no 18
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94410211612
The product you are viewing cross references to these numbers
Fits:
Porsche 924S 1986-88
Porsche 944 / 944 Turbo / 944 Turbo S 1985-89 (for cars with engine: 4405 / 4406 / 4407 / 4408 / 4409 / 4410 / 4411 / 4412 / 4451 / 4452)
Porsche 968 1992-95
Diagram ref no 18
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94410211612
94410211612
The product you are viewing cross references to these numbers
Price: £258.87
Orderable
Vehicle Group
- Porsche 944 2.5L 8V 1982-87
- Porsche 944 2.7L 8V 1988-89
- Porsche 944S 2.5L 16V 1987-88
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
- Porsche 968 3.0L 1992-94
- Porsche 968 Sport 3.0L 1994-95
- Porsche 968 CS 3.0L 1993-95
- Porsche 968 Turbo S 3.0L 1993-94
Information
Crankshaft gear wheel
The crankshaft gear wheel is installed on the front of the crankshaft and is responsible for driving the timing belt system that synchronizes the rotation of the crankshaft with the camshaft. In Porsche 944 and 968 engines, this gear forms the primary drive point for the timing system, ensuring that valve timing remains precisely aligned with piston movement.
Fits:
Porsche 944 1986-1991 with engine types M 44.40 and M 44.41
Porsche 968 1992-95 with engine types M 43 and M 44.
Diagram ref no 15
This OE Match version of part number 94410512507 is designed to match the factory specifications used in Porsche engines, providing accurate tooth geometry and reliable engagement with the timing belt and associated components.
The crankshaft gear transfers rotational motion from the crankshaft to the timing belt system. This ensures the camshaft opens and closes the engine valves at the correct time relative to piston movement, maintaining proper combustion and engine performance.
If the gear becomes worn or damaged, the timing system may lose accuracy, which can affect engine efficiency and reliability.
Function
• Timing Drive: Transfers crankshaft rotation to the camshaft timing system
• Engine Synchronization: Maintains precise timing between pistons and valves
• Power Transmission: Drives the timing belt mechanism
• Engine Reliability: Ensures stable and accurate valve timing
Timing system components are subjected to constant load and engine vibration. Over time the gear teeth may wear or become damaged, which can affect timing belt alignment and engine timing accuracy. Replacing the crankshaft gear during major engine service or timing system overhaul helps ensure precise timing operation and protects other components in the engine’s timing system.
Consider replacing the crankshaft gear wheel when:
• Performing a timing belt or engine rebuild service
• Gear teeth show wear or damage
• Timing system components are being replaced
• Engine timing alignment issues are detected
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94410512507
The product you are viewing cross references to these numbers
The crankshaft gear wheel is installed on the front of the crankshaft and is responsible for driving the timing belt system that synchronizes the rotation of the crankshaft with the camshaft. In Porsche 944 and 968 engines, this gear forms the primary drive point for the timing system, ensuring that valve timing remains precisely aligned with piston movement.
Fits:
Porsche 944 1986-1991 with engine types M 44.40 and M 44.41
Porsche 968 1992-95 with engine types M 43 and M 44.
Diagram ref no 15
This OE Match version of part number 94410512507 is designed to match the factory specifications used in Porsche engines, providing accurate tooth geometry and reliable engagement with the timing belt and associated components.
The crankshaft gear transfers rotational motion from the crankshaft to the timing belt system. This ensures the camshaft opens and closes the engine valves at the correct time relative to piston movement, maintaining proper combustion and engine performance.
If the gear becomes worn or damaged, the timing system may lose accuracy, which can affect engine efficiency and reliability.
Function
• Timing Drive: Transfers crankshaft rotation to the camshaft timing system
• Engine Synchronization: Maintains precise timing between pistons and valves
• Power Transmission: Drives the timing belt mechanism
• Engine Reliability: Ensures stable and accurate valve timing
Timing system components are subjected to constant load and engine vibration. Over time the gear teeth may wear or become damaged, which can affect timing belt alignment and engine timing accuracy. Replacing the crankshaft gear during major engine service or timing system overhaul helps ensure precise timing operation and protects other components in the engine’s timing system.
Consider replacing the crankshaft gear wheel when:
• Performing a timing belt or engine rebuild service
• Gear teeth show wear or damage
• Timing system components are being replaced
• Engine timing alignment issues are detected
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94410512507
94410512507
The product you are viewing cross references to these numbers
Price: £225.00
Orderable
Information
Bearing clearance gauge pack
100 Plasigauge strips per box
Related reference numbers
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PLA007
The product you are viewing cross references to these numbers
100 Plasigauge strips per box
PLASTIGAUGE PL-A is widely used in the measurement of clearance in plain automotive bearings. Measurement of clearance in big-end bearings can be achieved without dismantling the crankshaft.
For measurements of: 0.001″ to 0.007″ (0.025mm – 0.175mm)
Suitable for use at temperatures between 0°C and 35°C
Contents:
Related reference numbers
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PLA007
PL-A
The product you are viewing cross references to these numbers
Price: £50.89
In stock