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- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- 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 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
Fits:
Porsche 996 3.6L 2001>> M96.03
Porsche 997 3.8L M97.01
Porsche 997 3.6L M96.05
Porsche 987 Boxster 3.4L
Click 'Zoom in' for large parts diagram.
Diagram Ref No 9.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610527102
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 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
Valve Spring
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The Porsche Valve Spring is a critical component
of the valve train system fitted to numerous Porsche 911 and Porsche 964 models
from 1965 to 1994. Designed to maintain precise valve operation throughout the
engine's RPM range, the valve spring ensures that intake and exhaust valves
close correctly after being opened by the camshaft.
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 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
Diagram Ref No 13
In Porsche's legendary air-cooled flat-six engines, accurate valve control is essential for maintaining combustion efficiency, engine performance, reliability, and long-term durability. The valve spring works continuously under extreme mechanical stress, cycling thousands of times per minute to keep the valve train operating correctly.
Whether you're rebuilding a classic Porsche engine, restoring a 911, or carrying out a cylinder head overhaul, replacing worn valve springs helps maintain factory performance and reduces the risk of costly engine damage.
What Does the Valve Spring Do?
The valve spring is responsible for returning the intake and exhaust valves to their closed position after each opening cycle generated by the camshaft.
Its key functions include:
- Maintaining correct valve timing operation
- Ensuring valves close fully and consistently
- Keeping the valve train under proper tension
- Preventing valve float at higher engine speeds
- Supporting engine compression and combustion efficiency
- Protecting the valve train from instability and excessive wear
Without adequate spring tension, valves may not close correctly, leading to poor performance and potential engine damage.
Why Does the Valve Spring Fail?
Valve springs are constantly subjected to compression, heat, vibration, and high engine speeds. Over time, these factors can lead to material fatigue and a gradual loss of spring tension.
Common causes of valve spring failure include:
- Metal fatigue from repeated cycling
- High mileage wear
- Prolonged exposure to engine heat
- Over-revving the engine
- Corrosion or contamination
- Performance modifications increasing valve train loads
- Age-related weakening of spring material
- Improper engine assembly or valve train geometry
As spring pressure decreases, valve control becomes less precise, particularly at higher RPM.
Common Symptoms of Worn Valve Springs
A weakened or damaged valve spring may cause:
- Loss of engine performance
- Valve float at higher RPM
- Rough idle
- Engine misfires
- Increased valve train noise
- Reduced power output Inconsistent compression readings
- Premature wear of valves, guides, and camshaft components
In severe cases, a broken valve spring can result in valve-to-piston contact and major engine damage.
When Should You Replace Valve Springs?
Valve springs should be inspected whenever the cylinder heads are removed and replaced if any signs of fatigue or wear are detected.
Replacement is strongly recommended:
- During complete engine rebuilds
- During cylinder head refurbishment
- On high-mileage engines
- When installing performance camshafts
- If valve float is present
- When spring tension falls below specification
- During preventative maintenance on restoration projects
- Whenever a spring shows signs of corrosion or damage
Many experienced Porsche engine builders replace all valve springs during rebuilds to ensure consistent valve train performance and long-term reliability.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90110590151
The product you are viewing cross references to these numbers
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) TURBO 3.3L 1991-93
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
Click 'Zoom in' for large parts diagram.
Diagram Ref No 10.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93010541950
The product you are viewing cross references to these numbers
- 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) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
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
Related, superseded, cross reference or alternative numbers for comparison.
93010540901
The product you are viewing cross references to these numbers