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bearing shell Genuine Porsche part 91110113300

Code: 91110113300

Genuine Porsche part

bearing shell

The product code 91110113300 was also found on these diagrams

102-00 - bearing shell ii - vii

Crankshaft 911 1974-77

102-00 - bearing shell ii - vii

crankshaft 911 TURBO 1975-77

Additional information:

• This part is brand new and unused.
• Please verify that it is 100% suitable for your specific vehicle before purchase to ensure compatibility.

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Related products

Engine head studs upper standard. Porsche 911 1974-89

91110117200/1

Product Information

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

91110117200

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bearing shell Genuine Porsche part 91110113300