Engine Valves / Guides / Springs

Engine cylinder head exhaust valve.



Fits:

Porsche 930 turbo 3.0ltr - 1975 to 1977
Porsche 930 turbo 3.3ltr - 1978 to 1989
Porsche 964 turbo 3.3ltr - 1991 to 1992

Diameter - 41.5mm

Click 'Zoom in' for large parts diagram.
Diagram Ref No 10.

Related reference numbers
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93010541950

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Engine cylinder head exhaust valve.



Fits:
Porsche 930 turbo 3.0ltr - 1975 to 1977
Porsche 930 turbo 3.3ltr - 1978 to 1989
Porsche 964 turbo 3.3ltr - 1991 to 1992

Diameter - 41.5mm

Click 'Zoom in' for large parts diagram.
Diagram Ref No 10.

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Related, superseded, cross reference or alternative numbers for comparison.

93010541950

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Engine Cylinder Head Inlet Valve.

This OE Engine Cylinder Head Inlet Valve is a Porsche 911 / 964 engine component designed to regulate the intake of air and fuel mixture into the combustion chamber. Installed within the cylinder head, the inlet valve opens and closes in precise timing with the engine cycle, ensuring efficient airflow for combustion and optimal engine performance.
Sold Each.
x6 Required Per Car.

Fits:

• 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 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93

  
Diagram Ref No 9

What This Product Does:

• Controls intake airflow into the combustion chamber
• Opens and closes in sync with engine timing
• Supports efficient combustion and power generation
• Maintains correct air/fuel mixture flow
• Contributes to engine performance, efficiency, and emissions control

Symptoms Of Wear Or Failure:

• Engine misfires or rough idle
• Loss of power or poor acceleration
• Reduced compression in the affected cylinder
• Excessive fuel consumption
• Ticking or tapping noises from the cylinder head
• Burnt, bent, or carbon-covered valve surfaces
• Check engine light related to combustion faults  

Why Replacement Matters:

• Restores proper airflow and combustion efficiency
• Improves engine power and throttle response
• Maintains correct compression and cylinder sealing
• Reduces fuel consumption and emissions
• Prevents further engine damage caused by valve failure
• Ensures long-term engine reliability and smooth operation

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

96410540908

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Engine Cylinder Head Inlet Valve.

This MAHLE Engine Cylinder Head Inlet Valve is a Porsche 911 / 964 engine component designed to regulate the intake of air and fuel mixture into the combustion chamber. Installed within the cylinder head, the inlet valve opens and closes in precise timing with the engine cycle, ensuring efficient airflow for combustion and optimal engine performance.
Sold Each.
x6 Required Per Car.

Fits:

• 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 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93

  
Diagram Ref No 9

What This Product Does:

• Controls intake airflow into the combustion chamber
• Opens and closes in sync with engine timing
• Supports efficient combustion and power generation
• Maintains correct air/fuel mixture flow
• Contributes to engine performance, efficiency, and emissions control

Symptoms Of Wear Or Failure:

• Engine misfires or rough idle
• Loss of power or poor acceleration
• Reduced compression in the affected cylinder
• Excessive fuel consumption
• Ticking or tapping noises from the cylinder head
• Burnt, bent, or carbon-covered valve surfaces
• Check engine light related to combustion faults  

Why Replacement Matters:

• Restores proper airflow and combustion efficiency
• Improves engine power and throttle response
• Maintains correct compression and cylinder sealing
• Reduces fuel consumption and emissions
• Prevents further engine damage caused by valve failure
• Ensures long-term engine reliability and smooth operation

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

96410540908

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Engine cylinder head inlet valve
Manufactured to OEM specifications, this valve matches the factory dimensions, seat angle, and stem diameter for perfect sealing and valve timing accuracy. Built from high-grade heat-resistant steel, it delivers excellent thermal stability and wear resistance, ideal for the demanding environment of Porsche’s high-revving flat-six engines.

Fits:
Porsche 964 C2/C4 3.6L 1990-94
Porsche 911 3.3L Turbo 1978-89
911 (964), 3.3 Turbo M 30.69
911 (964), 3.3 Turbo S M 30.69S
911 (964), 3.6 Carrera M 64.01/M 64.02
911 (964), 3.6 Carrera M 64.01/M 64.02
911 (964), 3.6 Carrera 4 M 64.01
911 (964), 3.6 Carrera RS M 64.03
911 (964), 3.6 Turbo M 64.50
911 Cabriolet (964), 3.6 Carrera M 64.01/M 64.02
911 Cabriolet (964), 3.6 Carrera M 64.01/M 64.02
911 Cabriolet (964), 3.6 Carrera 4 M 64.01
911 Speedster (964), 3.6 CarreraM 64.01/M 64.02
911 Speedster (964), 3.6 CarreraM 64.01/M 64.02
911 Targa (964), 3.6 Carrera M 64.01/M 64.02
911 Targa (964), 3.6 Carrera M 64.01/M 64.02
911 Targa (964), 3.6 Carrera 4 M 64.01

Valve head diameter 9,00 mm
Valve stem diameter 9,00 mm
Valve shaft length 110,10 mm
Valve seat angle 45 °

Diagram Ref No 11.

Function:
The inlet valve controls the flow of air-fuel mixture into the combustion chamber. Proper sealing and timing are essential for maintaining compression, combustion efficiency, and overall power output. A high-quality OE Match valve ensures consistent intake airflow, reliable operation, and long engine life.

Why & When Replacement Matters

Why: Over time, inlet valves experience wear from heat, carbon build up, and mechanical stress, which can lead to reduced compression, power loss, and rough engine operation.
When: During engine rebuilds or cylinder head servicing If there are signs of valve leakage, pitting, or stem wear.  When experiencing loss of power, misfires, or compression imbalance. As preventive maintenance on high-mileage engines or performance builds.

Related reference numbers
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93010540901

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Exhaust valve, (Sodium-filled).
This is a sodium-filled exhaust valve designed to Porsche’s original specifications, as used in 964 Carrera (C2 / C4) 3.6L engines (1990–94). The sodium fill helps dissipate heat from the valve head into the valve stem, improving thermal management under exhaust conditions.
Sold each, 6 required per car.

Fits:
Porsche 964 Carrera 2 / Carrera 4  3.6L 1989 - 1994 (M64.01 / M64.02)
Porsche 964 RS Carrera 3.6L 1991 - 1994 (M96.03)

Diagram Ref No 12.

What exhaust valve does:
• Seals the combustion chamber on the exhaust side, opening and closing at the correct times to allow exhaust gases to exit
• The internal sodium enhances heat transfer, reducing valve temperature, helping prevent distortion or burning
•  Works in tandem with valve springs, guides, and seats to maintain consistent cylinder head performance

Over time, exhaust valves undergo extreme heat cycles, which can lead to wear, bending, warping, or pitting on the sealing face.  A faulty or damaged exhaust valve can lead to compression loss, misfires, reduced power, excessive smoking, or engine damage. Replacement improves reliability, restores engine efficiency, and ensures long life under high temperature conditions

•  It fits in the cylinder head’s exhaust valve seat for Porsche 964 the exhaust port side of each combustion chamber
•  The valve stem goes through the valve guide in the head, and the head of the valve seals against the exhaust seat when closed, with its tip actuated by the rocker or cam mechanism.

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96410541903

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Feeler gauge with blade



Fits:
Porsche 911 1965-89
Porsche 964 - 1989 to 1994
Porsche 356
Porsche 914/6

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00072121320

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Inlet Valve Guide 1st Oversize.

The TRW 1st Oversize Inlet Valve Guide is a precision replacement cylinder-head component designed to support and correctly locate the inlet valve as it opens and closes.

Fits:

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93  

Diagram Ref No 2A

The valve guide keeps the valve stem accurately aligned with the valve seat, allowing the inlet valve to move smoothly while maintaining the correct seating position when closed. Correct valve guidance is essential for maintaining cylinder compression, efficient combustion and reliable engine performance.

This 1st oversize version is intended for cylinder-head refurbishment where the valve-guide mounting bore has worn or has been machined beyond the dimensions suitable for a standard-size guide. The oversize outer diameter allows the correct interference fit to be restored during professional cylinder-head rebuilding.

What This Product Does:

• Supports and accurately guides the inlet valve stem.
• Keeps the valve correctly aligned with its valve seat.
• Controls excessive sideways movement of the valve.
• Helps the valve form an effective seal when closed.
• Supports correct cylinder compression.
• Helps maintain efficient intake airflow and combustion.
• Reduces abnormal wear on the valve stem and valve seat.
• Provides an oversize fit for cylinder heads requiring refurbishment.
• Helps restore correct valvetrain operation during an engine or cylinder-head rebuild.

As valve guides wear, they become less effective at locating the valve accurately against the valve seat. This can reduce the effectiveness of the combustion-chamber seal and adversely affect engine performance.

Symptoms Of Wear Or Failure:
A worn inlet valve guide may cause:

• Increased engine oil consumption.
• Blue or blue-grey exhaust smoke.
• Smoke after start-up or following periods of overrun.
• Excessive valve-stem movement or lateral play.
• Ticking or tapping noises from the cylinder head.
• Rough or unstable idle.
• Engine misfires.
• Reduced engine performance.
• Poor or uneven cylinder compression.
• Oil-fouled spark plugs.
• Carbon deposits around the inlet valve.
• Excessive valve-stem or valve-seat wear.
• Poor valve seating.
• Excessive valve-guide clearance found during engine inspection.

Some of these symptoms can also be caused by valve-stem seals, piston rings or other engine components, so correct diagnosis and measurement are important before replacement.

Why Replacement Matters:
Valve guides operate continuously whenever the engine is running and are subjected to friction, heat and rapid reciprocating valve movement. With age and mileage, clearance between the valve stem and guide can increase.

Excessive clearance allows the valve to move laterally rather than travelling accurately along its intended axis. This can prevent the valve from consistently contacting the valve seat correctly, compromising combustion-chamber sealing and accelerating wear of the valve, valve seat and surrounding cylinder-head components.

Worn inlet guides can also allow increased quantities of engine oil to pass down the valve stem into the intake port and combustion chamber, contributing to oil consumption, exhaust smoke and deposits.

Replacing worn guides helps to:

• Restore accurate valve alignment.
• Maintain correct valve seating.
• Reduce unwanted valve-stem movement.
• Support consistent compression.
• Control oil entering the combustion chamber.
• Protect new or reconditioned valves and valve seats.
• Restore reliable cylinder-head operation.
• Reduce the risk of more extensive cylinder-head damage.

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96410432152

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Valve cotter half. 
Sold each - 2 required per engine valve



Fits:
Porsche 356C / SC - 1963 to 1965
Porsche 911 - 1965 to 1989
Porsche 964 - 1989 to 1994
Porsche 944 - 1982 to 1991
Porsche 928 - 1978 to 1986

Click 'Zoom in' for large parts diagram.
Diagram ref no 16

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90110541700

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Valve Cotter Half.

The TRW Valve Cotter Half is a replacement valve-spring retaining collet for selected classic Porsche engines.
Sold Each.
x2 Required Per Engine Valve.

Fits:

• Porsche 356C / SC - 1963 to 1965
• Porsche 911 - 1965 to 1989
• Porsche 964 - 1989 to 1994
• Porsche 944 - 1982 to 1991
• Porsche 928 - 1978 to 1986

Diagram Ref No 16

Also known as a valve keeper, valve collet or valve lock, this small but critical component fits into the machined groove near the top of the valve stem and locks into the valve spring retainer.

Each valve requires two cotter halves. When installed together, the two halves form a tapered locking arrangement that secures the valve spring and spring retainer to the valve stem.

What This Product Does:
The valve cotter forms part of the cylinder-head valvetrain.

Its job is to mechanically lock the valve spring retainer to the valve stem.

The assembly typically consists of:

• Engine valve
• Valve spring
• Spring retainer
• Two valve cotter halves

When the valve spring is compressed during assembly, the two cotter halves are installed around the valve-stem groove.

As the spring compressor is released, the spring retainer presses against the tapered outside surface of the cotters and locks them securely into position.

This allows the spring to remain attached to the valve while the engine operates at high speed.

Symptoms Of Wear Or Failure:
Valve cotters usually do not produce gradual external symptoms in the same way as a bearing or seal.

Problems are most commonly discovered during cylinder-head inspection or after another valvetrain fault develops.

Possible warning signs include:

• Unusual valvetrain ticking
• Metallic noise from the cylinder head
• Valve spring retainer sitting incorrectly
• Visible cotter movement
• Uneven cotter seating
• Damaged valve-stem groove
• Cracked or chipped cotter
• Wear marks around the locking surfaces
• Spring retainer sitting at an abnormal angle
• Valve clearance changing unexpectedly
• Misfire following valvetrain damage
• Loss of compression
• Serious mechanical noise after a cotter releases

A correctly installed cotter should remain securely locked and should not visibly move relative to the spring retainer.

Why Replacement Matters:
A damaged valve cotter should never be ignored.

If the cotter loses its grip on the valve stem, the spring retainer can release.

This can allow the valve to drop into the cylinder.

Potential consequences include:

• Valve-to-piston contact
• Bent valve
• Damaged piston
• Broken valve guide
• Cylinder-head damage
• Combustion-chamber damage
• Severe engine failure

Because the possible consequences are so serious, questionable cotters should be replaced during cylinder-head service rather than reused.

Related reference numbers
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90110541700

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Valve guide 1st oversize.
Inlet and exhaust.



Fits:
Porsche 964 C2 / C4 1989-94

Click 'Zoom in' for large parts diagram.
Diagram Ref No 2, 2A.

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964104321

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