Please wait… 
Please wait while we process your order,
do not press the back button…
do not press the back button…
Enter your VAT number here and click Verify:
Your details have been verified. VAT number registered to:
,
.
Your order will now be zero rated for VAT purposes. We reserve the right to verify these details after your order request has been made and reinstate VAT if required.
Your VAT details were not recognised or were invalid. Your VAT number must be matched to your Billing Country as specified above. This is currently specified as . You do not need to enter the country code part of your VAT number as this has already been selected in your billing address details above.
The VAT number checking service is currently offline. Please supply your VAT details within the comments or special instructions field below and we will apply a VAT discount after placing your order request.
Valve control adjustment hexagon nut M8x1 SET OF 12 Porsche 911 / 964 / 914 - 99903400500
99903400500/1x12
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 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 914 (1970-1976)
Information
Hexagon nut M8x1 for valve control adjustment screw, left.
This locking nut is critical in maintaining the correct clearance setting between the rocker-arm or cam follower and valve stem, ensuring reliable valvetrain performance and correct engine behavior.
SET OF 12
Fits:
Porsche 911 1973 - 1989
Porsche 911 Turbo 1975 - 1989
Porsche 964 C2 / C4 / RS 1989 - 1994
Porsche 964 Turbo 1991 - 1994
Porsche 914 1970 - 1976
Porsche 914/6 1970 - 1972
Diagram ref no 50
• Position on Vehicle: Engine cylinder head, at the valve adjusting screw area - used to lock the adjuster once clearance is set.
• Function: Locks the valve-adjusting screw in place, ensures the correct clearance remains unchanged under engine operation, prevents loosening of adjuster and ensures valvetrain reliability.
• Specification: M8 × 1 thread, correct height and socket size, treated or coated for durability - direct-fit replacement of Porsche part number 99903400500.
• Applications: Ideal when your original nut is damaged, the adjuster is loose, you are doing a valve-clearance service, or you require reliable hardware for engine rebuilds.
While small, this locking nut performs a vital role: without it, the adjuster can drift, valve clearance can open up or close down, leading to noisy operation, performance loss, premature wear or even engine damage. Symptoms of a failing/incorrect nut include adjusting screw backing out, noisy valvetrain, incorrect clearance and poor idle or performance.
When to replace:
• The adjuster locking nut is missing, corroded, rounded or damaged.
• After valve-clearance adjustment and you want guaranteed lock-in of the setting.
• During engine rebuild or cylinder-head service when valvetrain hardware is exposed.
• To replace the original with fresh hardware to maintain service integrity and reliability.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99903400500
The product you are viewing cross references to these numbers
This locking nut is critical in maintaining the correct clearance setting between the rocker-arm or cam follower and valve stem, ensuring reliable valvetrain performance and correct engine behavior.
SET OF 12
Fits:
Porsche 911 1973 - 1989
Porsche 911 Turbo 1975 - 1989
Porsche 964 C2 / C4 / RS 1989 - 1994
Porsche 964 Turbo 1991 - 1994
Porsche 914 1970 - 1976
Porsche 914/6 1970 - 1972
Diagram ref no 50
• Position on Vehicle: Engine cylinder head, at the valve adjusting screw area - used to lock the adjuster once clearance is set.
• Function: Locks the valve-adjusting screw in place, ensures the correct clearance remains unchanged under engine operation, prevents loosening of adjuster and ensures valvetrain reliability.
• Specification: M8 × 1 thread, correct height and socket size, treated or coated for durability - direct-fit replacement of Porsche part number 99903400500.
• Applications: Ideal when your original nut is damaged, the adjuster is loose, you are doing a valve-clearance service, or you require reliable hardware for engine rebuilds.
While small, this locking nut performs a vital role: without it, the adjuster can drift, valve clearance can open up or close down, leading to noisy operation, performance loss, premature wear or even engine damage. Symptoms of a failing/incorrect nut include adjusting screw backing out, noisy valvetrain, incorrect clearance and poor idle or performance.
When to replace:
• The adjuster locking nut is missing, corroded, rounded or damaged.
• After valve-clearance adjustment and you want guaranteed lock-in of the setting.
• During engine rebuild or cylinder-head service when valvetrain hardware is exposed.
• To replace the original with fresh hardware to maintain service integrity and reliability.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99903400500
99903400500
The product you are viewing cross references to these numbers
About kit
This kit is comprised of the following items:
12 x Valve control adjustment hexagon nut M8x1 Porsche 911 / 964 / 914 (99903400500/1
Price: £15.00
In stock
Related products
Vehicle Group
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 996 TURBO 2000-05
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche 955 Cayenne S 4.5L V8 2003-06
- Porsche 955 Cayenne Turbo 4.5L 2003-06
Information
Camshaft hydraulic valve tappet exhaust.
Fits:
Porsche 987 MKI Boxster 2005-08
Porsche 987C MKI Cayman 2006-08
Porsche 996 Carrera 1998-05
Porsche 996 Turbo 2001-05
Porsche 997 MKI Carrera 2005-08
Porsche 955 Cayenne S / Turbo 4.5L 2003-06
Click 'Zoom in' for large parts diagram.
Diagram Ref No 5.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610504172
The product you are viewing cross references to these numbers
Fits:
Porsche 987 MKI Boxster 2005-08
Porsche 987C MKI Cayman 2006-08
Porsche 996 Carrera 1998-05
Porsche 996 Turbo 2001-05
Porsche 997 MKI Carrera 2005-08
Porsche 955 Cayenne S / Turbo 4.5L 2003-06
Click 'Zoom in' for large parts diagram.
Diagram Ref No 5.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610504172
99610504172
99610504172
99610504150
The product you are viewing cross references to these numbers
Price: £19.00
In stock