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- 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)
Upper Head / Barrel Stud – Sold Each
12 required except 2.7 Carrera RS where 24 are required (upper and lower)
The Porsche Upper Head / Barrel Stud is a critical engine
fastening component used in Porsche 911 models produced from 1973 to 1989. This
stud forms part of the cylinder head retention system that secures the engine
cylinders (barrels) and cylinder heads firmly to the crankcase, maintaining the
precise clamping force required for reliable engine operation.
Fits:
- Porsche 911 1973 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)
Diagram Ref No 2
Porsche's air-cooled flat-six engines rely on these studs to withstand enormous combustion pressures and continuous thermal expansion cycles. Without adequate clamping force, cylinder sealing can be compromised, leading to compression loss, oil leaks, exhaust gas leakage, and costly engine damage.
For most Porsche 911 models within this period, 12 upper head studs are required. The notable exception is the legendary Porsche 2.7 Carrera RS, which requires a complete set of 24 studs.
Whether you're carrying out a top-end rebuild, complete engine overhaul, or concours restoration, replacing ageing head studs is an important step in maintaining long-term engine reliability.
What Does the Upper Head / Barrel Stud Do?
The upper head stud provides the clamping force that secures the cylinder head and cylinder barrel assembly to the engine crankcase.
Its primary functions include:
- Securing the cylinder heads to the engine case
- Maintaining correct cylinder sealing pressure
- Preserving combustion chamber integrity
- Preventing movement between cylinders and heads
- Supporting stable engine compression
- Maintaining long-term engine reliability
The stud is constantly under tension and plays a crucial role in preserving the structural integrity of the entire engine assembly.
Why Does the Head Stud Fail?
Head studs operate under extreme conditions, being subjected to continuous heat cycles, combustion forces, vibration, and material expansion and contraction.
Common causes of failure include:
- Metal fatigue
- Corrosion and oxidation
- Age-related material degradation
- Thermal cycling stress
- Engine overheating
- Improper torque procedures during previous rebuilds
- High-mileage wear Long-term mechanical loading
Even on well-maintained engines, decades of operation can weaken original studs and reduce their ability to maintain the required clamping force.
Common Symptoms of a Failing Head Stud
A damaged or broken head stud can result in:
- Compression leaks
- Exhaust gas leakage between the cylinder and head
- Ticking noises from the cylinder heads
- Oil seepage around the cylinder base
- Reduced engine performance
- Uneven cylinder sealing
- Failed leak-down test results
- Visible broken studs during valve cover inspection
In some cases, a broken head stud may go unnoticed until routine valve adjustment or engine rebuild work is carried out.
When Should You Replace Head Studs?
Head studs should always be inspected during major engine work and replaced whenever wear, corrosion, or damage is identified.
Replacement is highly recommended:
- During top-end rebuilds
- During complete engine overhauls
- When one or more studs have broken
- During cylinder head refurbishment
- On high-mileage engines
- During preventative restoration projects
- When upgrading engine performance
- Whenever the cylinder heads are removed
Because replacing head studs requires significant engine disassembly, many Porsche specialists recommend replacement while access is available.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91110117200
The product you are viewing cross references to these numbers
- 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
Normally 24 studs per engine. Sold EACH
Fits:
Porsche 911 1965-89
Porsche 964 1989-94
Porsche 993 1994-98
This product supersedes Porsche's old part numbers:
- 99310117051
Solves the problems of loose head studs, The exhaust leak you hear in the 911 may actually be the cylinder head leaking where the studs have pulled loose. As Porsche increased displacement of the 911 engine, the different rates of thermal expansion have caused head studs to break or pull out from the engine case. These latest Dilavar steel head studs have a thermal expansion rate of approximately the same as the alloy case.
Click 'Zoom in' for large parts diagram.
Diagram Ref No 2.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99310117054
The product you are viewing cross references to these numbers
- 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
This complete set of 24 Dilavar cylinder head studs replaces all major head fasteners on air-cooled Porsche flat-six engines. Ideal for full rebuilds, upgrades, or resolving broken stud issues, the set provides factory-spec strength, corrosion resistance, and thermal stability. Fits 911, 964, and 993 engines (1965–98).
SET OF 24 STUDS (Original Porsche Quality)
Fits:
Porsche 911 1965 - 1989
Porsche 964 1989 - 1994
Porsche 993 1994 - 1998
Diagram Ref No 2.
Aged factory head studs can crack, corrode, or lose tension - especially after decades of heat cycling. Failure of a head stud can cause head leaks, combustion pressure loss, broken cylinders, or catastrophic engine damage. Installing new Dilavar studs ensures proper sealing, correct torque values, and long-term engine reliability.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99310117054
The product you are viewing cross references to these numbers
This kit is comprised of the following items:
- 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
Normally 24 studs per engine.
Solves the problems of loose head studs, The exhaust leak you hear in the 911 may actually be the cylinder head leaking where the studs have pulled loose. As Porsche increased displacement of the 911 engine, the different rates of thermal expansion have caused head studs to break or pull out from the engine case.
Superior Tested/Proven strength. (compared to Dilavar & Raceware)
Fits:
Porsche 911 1965-89
Porsche 964 1989-94
Porsche 993 1994-98
This product supersedes Porsche's old part numbers:
- 993 101 170 51
Click picture for large parts diagram.
Diagram Ref No 2.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99310117054
The product you are viewing cross references to these numbers