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Cylinder head studs. Porsche 911 / 964 / 993 1965-98 - 99310117054
99310117054/1
Vehicle Group
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- 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
Information
Cylinder head studs
This OE Match cylinder head stud is a replacement engine fastening stud for Porsche 911, 964, and 993 models from 1965 to 1998. It is designed to match the original-style fitment and function, helping secure the cylinder head and cylinder assembly correctly to the engine crankcase.
Sold individually, Normally 24 studs per engine
Fits:
Porsche 911 1965 - 1989
Porsche 964 1989 - 1994
Porsche 993 1994 - 1998
This product supersedes Porsche's old part numbers:
- 99310117051
Diagram Ref No 2.
The cylinder head stud provides the clamping force needed to hold the cylinder head, cylinder barrel, and engine case together. Correct head stud tension is essential for maintaining combustion sealing, cylinder stability, and reliable air-cooled engine operation.
Functions
• Secures the cylinder head and cylinder assembly to the engine case
• Provides correct clamping force for combustion sealing
• Supports cylinder and head alignment
• Helps maintain reliable engine sealing under heat and load
• Replaces corroded, stretched, broken, or damaged original studs
• Suitable for engine rebuilds, top-end repairs, and head stud replacement
• OE Match replacement for classic Porsche air-cooled engine repair
Why Replace This Part?
Cylinder head studs are exposed to high combustion forces, heat cycling, corrosion, vibration, and long-term engine load. Over time, studs can corrode, stretch, weaken, seize, or break. A damaged or broken head stud may cause compression leakage, oil seepage, cylinder head movement, exhaust leakage, poor running, or engine noise. Replacing worn or failed studs helps restore proper engine clamping and long-term reliability.
When to Replace This Part
• A cylinder head stud is broken, corroded, stretched, or damaged
• The engine has compression leakage or cylinder head sealing issues
• Oil seepage or combustion leakage is present around the cylinder/head area
• The engine is being rebuilt or overhauled
• The cylinder heads or barrels have been removed
• Existing studs are seized, heavily corroded, or unsuitable for reuse
• Preventative replacement is being carried out during top-end service.
Where it fits on the car
This cylinder head stud fits within the engine crankcase and extends through the cylinder barrel and cylinder head assembly. It forms part of the engine’s main cylinder/head fastening system and should be installed according to the factory engine layout and torque procedure.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99310117054
The product you are viewing cross references to these numbers
This OE Match cylinder head stud is a replacement engine fastening stud for Porsche 911, 964, and 993 models from 1965 to 1998. It is designed to match the original-style fitment and function, helping secure the cylinder head and cylinder assembly correctly to the engine crankcase.
Sold individually, Normally 24 studs per engine
Fits:
Porsche 911 1965 - 1989
Porsche 964 1989 - 1994
Porsche 993 1994 - 1998
This product supersedes Porsche's old part numbers:
- 99310117051
Diagram Ref No 2.
The cylinder head stud provides the clamping force needed to hold the cylinder head, cylinder barrel, and engine case together. Correct head stud tension is essential for maintaining combustion sealing, cylinder stability, and reliable air-cooled engine operation.
Functions
• Secures the cylinder head and cylinder assembly to the engine case
• Provides correct clamping force for combustion sealing
• Supports cylinder and head alignment
• Helps maintain reliable engine sealing under heat and load
• Replaces corroded, stretched, broken, or damaged original studs
• Suitable for engine rebuilds, top-end repairs, and head stud replacement
• OE Match replacement for classic Porsche air-cooled engine repair
Why Replace This Part?
Cylinder head studs are exposed to high combustion forces, heat cycling, corrosion, vibration, and long-term engine load. Over time, studs can corrode, stretch, weaken, seize, or break. A damaged or broken head stud may cause compression leakage, oil seepage, cylinder head movement, exhaust leakage, poor running, or engine noise. Replacing worn or failed studs helps restore proper engine clamping and long-term reliability.
When to Replace This Part
• A cylinder head stud is broken, corroded, stretched, or damaged
• The engine has compression leakage or cylinder head sealing issues
• Oil seepage or combustion leakage is present around the cylinder/head area
• The engine is being rebuilt or overhauled
• The cylinder heads or barrels have been removed
• Existing studs are seized, heavily corroded, or unsuitable for reuse
• Preventative replacement is being carried out during top-end service.
Where it fits on the car
This cylinder head stud fits within the engine crankcase and extends through the cylinder barrel and cylinder head assembly. It forms part of the engine’s main cylinder/head fastening system and should be installed according to the factory engine layout and torque procedure.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99310117054
99310117051
99310117053
99310117054
The product you are viewing cross references to these numbers
Price: €22.31
In stock
Related products
Information
HEX HEAD BOLT M12X1,5X110MM (extra long)
This Item is an Original Porsche Part found by using our original Porsche Part Number Search. If you are ordering parts via this method it is your responsibility to make sure that you enter and purchase the correct products for your vehicle. Please only use the searched product if you are sure of the part numbers as parts cannot be returned if ordered incorrectly.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90008214201L
The product you are viewing cross references to these numbers
This Item is an Original Porsche Part found by using our original Porsche Part Number Search. If you are ordering parts via this method it is your responsibility to make sure that you enter and purchase the correct products for your vehicle. Please only use the searched product if you are sure of the part numbers as parts cannot be returned if ordered incorrectly.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90008214201L
91137504300
90008214201
The product you are viewing cross references to these numbers
Price: €14.59
In stock
Vehicle Group
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 924 2.0L 1976-79
- Porsche 924 Turbo 2.0L 1979-81
- Porsche 924 Turbo 2.0L 1982-84
Information
Gearbox housing stud, M 8 X 38.
Fits:
Porsche 911 / SC / Carrera 1977-86
Porsche 911 Turbo 1977-77
Porsche 924 1976-79 with 5-Speed Gearbox
Porsche 924 Turbo/ GT 1980-85 Manual Gearbox G31.01/02/03
Click 'Zoom in' for large parts diagram.
Diagram ref no. 2 (for 911) or no.19 (for 924)
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99906209802
The product you are viewing cross references to these numbers
Fits:
Porsche 911 / SC / Carrera 1977-86
Porsche 911 Turbo 1977-77
Porsche 924 1976-79 with 5-Speed Gearbox
Porsche 924 Turbo/ GT 1980-85 Manual Gearbox G31.01/02/03
Click 'Zoom in' for large parts diagram.
Diagram ref no. 2 (for 911) or no.19 (for 924)
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99906209802
99906209802
The product you are viewing cross references to these numbers
Price: €5.14
Orderable
Vehicle Group
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 924 2.0L 1976-79
- Porsche 924 2.0L 1980-85
- Porsche 924 Turbo 2.0L 1979-81
- Porsche 924 Turbo 2.0L 1982-84
- Porsche 924 Carrera GT 2.0L 1981
- Porsche 924 Carrera GTS 2.0L 1982
- Porsche 924S 2.5L 1986-87
- Porsche 924S 2.5L 1988
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
- Porsche 928GTS 5.4L 1992-95
- Porsche 914 (1970-1976)
Information
Hex Head Bolt M8 x 16 used in various locations
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90007508704
The product you are viewing cross references to these numbers
Sold each
Fits:
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 924 2.0L 1976-79
- Porsche 924 2.0L 1980-85
- Porsche 924 Turbo 2.0L 1979-81
- Porsche 924 Turbo 2.0L 1982-84
- Porsche 924 Carrera GT 2.0L 1981
- Porsche 924 Carrera GTS 2.0L 1982
- Porsche 924S 2.5L 1986-87
- Porsche 924S 2.5L 1988
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
- Porsche 928GTS 5.4L 1992-95
- Porsche 914 (1970-1976)
The Hex Head Bolt M8 x 16 is a versatile, high-strength fastener used in multiple locations across classic Porsche models—including the Porsche 911, 914, 924 and 928. As a critical component in securing brackets, covers, engine parts, underbody panels and suspension-related hardware, this bolt ensures structural integrity and reliability throughout the vehicle.
What This Bolt Does
The Hex Head Bolt M8 x 16 plays a crucial role in securing various mechanical and body components on a Porsche.
Common Functions
- Secures brackets, panels and trim pieces
- Anchors engine and drivetrain components
- Holds suspension hardware and mountings
- Fastens interior and underbody parts
- Provides structural rigidity where load-bearing fasteners are required
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90007508704
90007508702
90007508703
90007508704
The product you are viewing cross references to these numbers
Price: €1.19
Arriving soon