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Cylinder head nut & washer kit. Porsche 911 1978-89 ❭ 99903109101K
- 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)
A complete fastening set of 24 cylinder head nuts and 24 head nut washers used to clamp the cylinder heads and cylinder barrels to the crankcase on classic air-cooled Porsche engines. This kit contains head nuts and "Large style washers"; used for 3.0 SC, 3.2 & 3.3 Turbo engines
Includes:
24 x 90110438204/1 - OE Match Cylinder head nuts
24 x 99903109101/1 - OE Match Head nut washers
Fits:
Porsche 911 1978 - 1989
Diagram ref no 16 and 17
This OE Match kit combines the correct-style M10 cylinder head nuts (OE ref no 90110438202) with the corresponding large head nut washers (OE ref no 99903109101). Together, they provide the correct bearing surface and clamping load distribution required during engine assembly or top-end rebuilds, helping maintain sealing integrity under heat cycling and high operating loads.
Head nuts and washers can suffer from corrosion, rounding, surface wear, and reduced load consistency after multiple rebuilds. Replacing them with OE-match hardware supports accurate torque application and helps maintain long-term clamp load stability - critical for top-end durability.
When to replace:
• During any top-end rebuild or head/cylinder removal
• Nuts show corrosion, damaged hex, or thread wear
• Washers are grooved, distorted, or heat-marked
• You suspect prior incorrect torqueing or hardware reuse history
• Preventive replacement on engines with unknown rebuild history
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99903109101K
The product you are viewing cross references to these numbers
This kit is comprised of the following items:
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Related, superseded, cross reference or alternative numbers for comparison.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
- Porsche 957 Cayenne S / GTS 4.8L 2007-10
- Porsche 957 Cayenne Turbo / Turbo S 4.8L 2007-10
- Porsche 958 Cayenne S V8 4.8L Petrol (400Hp) 2010-17
- Porsche 958 Cayenne S V8 4.2L Diesel (382Hp) 2010-17
- Porsche 958 Cayenne GTS V8 4.8L Petrol (400Hp) 2010-17
- Porsche 958 Cayenne Turbo V8 4.8L Petrol (500Hp) 2010-17
- Porsche 958 Cayenne Turbo S V8 4.8L Petrol (550Hp) 2010-17
- Porsche 970.1 Panamera V6 3.6L 2WD 2009-13
- Porsche 970.1 Panamera 4 V6 3.6L 4WD 2009-13
- Porsche 970.1 Panamera S V8 4.8L 2009-13
- Porsche 970.1 Panamera 4S V8 4.8L 2009-13
- Porsche 970.1 Panamera GTS V8 4.8L 2011-13
- Porsche 970.1 Panamera Turbo V8 4.8L 2009-13
- Porsche 970.1 Panamera Turbo S V8 4.8L 2009-13
- Porsche 970.2 Panamera V6 3.6L 2WD (310Hp) 2014-16
- Porsche 970.2 Panamera 4 V6 3.6L 4WD (310Hp) 2014-16
- Porsche 970.2 Panamera GTS V8 4.8L 4WD (440Hp) 2014-16
- Porsche 970.2 Panamera Turbo V8 4.8L (520Hp) 2014-16
- Porsche 970.2 Panamera Turbo V8 Executive 2014-16
- Porsche 970.2 Panamera Turbo S V8 4.8L 2014-16
Porsche Camshaft Adjuster Bolt - M12 x 1,5 x 110
Precision Camshaft Timing Securing Bolt for Porsche Engines
The camshaft adjuster bolt (part number is a
critical fastening component used in the variable camshaft timing system, this bolt secures the camshaft adjuster unit to the
camshaft assembly.
Fits:
- Porsche 957 Cayenne S / GTS 4.8L 2007-10
- Porsche 957 Cayenne Turbo / Turbo S 4.8L 2007-10
957 Cayenne - From engine numbers
M905541
MG904965
M901689
MT901788
MS900562
- Porsche 958 Cayenne S V8 4.8L Petrol (400Hp) 2010-17
- Porsche 958 Cayenne S V8 4.2L Diesel (382Hp) 2010-17
- Porsche 958 Cayenne GTS V8 4.8L Petrol (400Hp) 2010-17
- Porsche 958 Cayenne Turbo V8 4.8L Petrol (500Hp) 2010-17
- Porsche 958 Cayenne Turbo S V8 4.8L Petrol (550Hp) 2010-17
- Porsche 970.1 Panamera V6 3.6L 2WD 2009-13
- Porsche 970.1 Panamera 4 V6 3.6L 4WD 2009-13
- Porsche 970.1 Panamera S V8 4.8L 2009-13
- Porsche 970.1 Panamera 4S V8 4.8L 2009-13
- Porsche 970.1 Panamera GTS V8 4.8L 2011-13
- Porsche 970.1 Panamera Turbo V8 4.8L 2009-13
- Porsche 970.1 Panamera Turbo S V8 4.8L 2009-13
- Porsche 970.2 Panamera V6 3.6L 2WD (310Hp) 2014-16
- Porsche 970.2 Panamera 4 V6 3.6L 4WD (310Hp) 2014-16
- Porsche 970.2 Panamera GTS V8 4.8L 4WD (440Hp) 2014-16
- Porsche 970.2 Panamera Turbo V8 4.8L (520Hp) 2014-16
- Porsche 970.2 Panamera Turbo V8 Executive 2014-16
- Porsche 970.2 Panamera Turbo S V8 4.8L 2014-16
Diagram ref no 10
It plays a vital role in maintaining correct valve timing and engine performance.
What the Camshaft Adjuster Bolt Does
The Porsche engines use a variable valve timing system, often referred to as VarioCam, to optimise engine efficiency, torque and power output across the rev range.
The camshaft adjuster:
- Alters camshaft timing based on engine load and RPM
- Improves low-end torque and high-end power
- Enhances fuel efficiency
- Reduces emissions
- Maintains smooth engine operation
The camshaft adjuster bolt secures the timing adjuster mechanism firmly in place. Correct torque and clamping force are essential to ensure precise camshaft alignment and stable timing control.
Why Camshaft Adjuster Bolts Fail
Camshaft adjuster bolts are subject to:
- High rotational forces
- Continuous vibration
- Heat cycling from engine operation
- Torque stress during installation
In many cases, these bolts are torque-to-yield fasteners, meaning they are designed for single-use installation. Reusing an old bolt can result in reduced clamping force or improper seating.
Failure or incorrect installation can lead to:
- Timing deviation fault codes
- Rattling noises from the camshaft area
- Poor engine performance
- Check engine light illumination
- Severe engine damage if timing shifts significantly
Why You May Need a Replacement Camshaft Adjuster Bolt
Whenever the camshaft adjuster, timing components or camshafts are removed, the securing bolt should be replaced to maintain correct torque specifications.
This camshaft adjuster bolt is essential during:
- VarioCam repairs
- Timing chain service
- Camshaft replacement
- Engine rebuilds
- Cylinder head work
- Fault code diagnosis relating to camshaft timing
Replacing the bolt ensures proper clamping force and protects the integrity of the Porsche timing system.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94810525400
The product you are viewing cross references to these numbers
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