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Original Porsche Part Genuine Porsche part 61610432250
• This part is brand new and unused.
• Please verify that it is 100% suitable for your specific vehicle before purchase to ensure compatibility.
Before purchasing thoroughly check part to confirm compatibility.
- We are unable to provide fitting details for this product at this time. Please contact us for further information.
Cylinder Head Nut
Sold each - 24 required for the 911
Maintain the integrity and reliability of your Porsche
engine rebuild with this OE Match Cylinder Head Nut 90110438204. Designed for
use on Porsche 356B, 356C, 912 and classic 911 air-cooled engines, this
precision-engineered fastener plays a critical role in securing the cylinder
head assembly to the engine.
Fits:
- 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 356B 1959-63
- Porsche 356C 1963-65
Diagram Ref No 17
Although small in size, cylinder head nuts are among the most important fasteners in any engine. They provide the clamping force required to maintain an effective seal between the cylinder heads, cylinders and engine case, ensuring correct compression, combustion efficiency and long-term engine reliability.
Manufactured to OE Match specifications, this cylinder head nut is ideal for engine rebuilds, top-end overhauls, cylinder head refurbishment and concours restorations.
What Does a Cylinder Head Nut Do?
The cylinder head nut secures the cylinder head assembly to the engine using the cylinder head studs.
Its primary functions include:
- Maintaining cylinder head clamping force
- Ensuring correct cylinder sealing
- Supporting combustion chamber integrity
- Maintaining engine compression
- Preventing cylinder head movement
- Supporting reliable engine operation
- Helping prevent oil and combustion leaks
Correct clamping force is essential for maintaining engine performance and durability.
Why Do Cylinder Head Nuts Fail?
Cylinder head nuts are exposed to repeated heat cycles, vibration and engine loads throughout their service life.
Common causes of deterioration include:
- Corrosion
- Thread wear
- Fatigue from repeated heat cycles
- Over-tightening
- Incorrect installation procedures
- Engine overheating
- Age-related degradation
- Damage during previous rebuilds
In older air-cooled Porsche engines, decades of service can leave original hardware weakened or unsuitable for reuse.
Symptoms of Worn or Damaged Cylinder Head Hardware
Potential warning signs include:
- Loss of cylinder sealing
- Compression leaks
- Oil seepage around cylinder heads
- Difficulty achieving correct torque settings
- Damaged threads
- Corroded hardware
- Uneven clamping loads
- Engine rebuild inspection failures
Many of these issues are discovered during engine disassembly rather than during normal operation.
When Should Cylinder Head Nuts Be Replaced?
Replacement is strongly recommended when:
- Rebuilding an engine
- Carrying out a top-end overhaul
- Replacing cylinder head studs
- Refurbishing cylinder heads
- Corrosion is present
- Threads show signs of wear
- Factory specifications require replacement
Most professional Porsche engine builders replace critical fastening hardware during major engine work to ensure long-term reliability.
Why Replacement Matters
Reusing worn or damaged cylinder head hardware can compromise engine sealing and reliability.
Benefits of replacement include:
- Correct clamping force
- Improved sealing performance
- Reduced risk of leaks
- Improved engine reliability
- Professional rebuild standards
- Long-term durability
- Factory-correct restoration quality
- Greater peace of mind
For classic Porsche engines, replacing critical hardware is inexpensive insurance against future engine issues.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90110438204
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 356B 1959-63
- Porsche 356C 1963-65
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12 Month Warranty
Worldwide Delivery
Fits:
Porsche 912 1.6L
Click 'Zoom in' for large parts diagram.
Diagram ref no 4
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
61610431652
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
Shop Securely
12 Month Warranty
Worldwide Delivery
Exhaust valve guide (exhaust outlet) is Standard replaces, engineered to match factory dimensions. The valve guide is a cylindrical sleeve pressed into the cylinder head, guiding the motion of the exhaust valve stem and maintaining alignment and clearance.
Sold each.
Fits:
Porsche 912 1.6L
Porsche 356
Diagram ref no 5
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
61610432260
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 356 1950-55
- Porsche 356A 1955-59
Shop Securely
12 Month Warranty
Worldwide Delivery
Fits:
Porsche 912 1.6L
Click 'Zoom in' for large parts diagram.
Diagram ref no 5
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
61610432162
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
Fits:
Porsche 912 1.6L
Click 'Zoom in' for large parts diagram.
Diagram ref no 6
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
61610549102
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
Shop Securely
12 Month Warranty
Worldwide Delivery
Fits:
Porsche 912 1965-69
Click 'Zoom in' for large parts diagram.
Diagram ref no 30
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
61610439300
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
Shop Securely
12 Month Warranty
Worldwide Delivery
24 per engine. Price is for each.
Fits:
Porsche 911 1965-89 all models
Click 'Zoom in' for large parts diagram.
Diagram Ref No 17.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90110438204
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)
Shop Securely
12 Month Warranty
Worldwide Delivery
Fits:
Porsche 356 B / C 1960-69
Porsche 912 1965-69
Click 'Zoom in' for large parts diagram.
Diagram ref no 20
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
61610438101
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 356B 1959-63
- Porsche 356C 1963-65
Shop Securely
12 Month Warranty
Worldwide Delivery
Fits:
Porsche 356 B / C 1960-69
Porsche 912 1965-69
Click 'Zoom in' for large parts diagram.
Diagram ref no 21
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
61610438300
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 356B 1959-63
- Porsche 356C 1963-65
Shop Securely
12 Month Warranty
Worldwide Delivery
Monday-Friday: 8.30am - 5.30pm (GMT)
Saturday: Closed
Sunday: Closed