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Porsche // 911 & 912 (1965-1989) // 911 1978-1989 3.3L Turbo (930)
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- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
Valve Head Ø: 50 mm, Valve Stem Ø: 8 mm, Valve Shaft Length: 110,4 mm, Valve Seat Angle: 45 °.
Fits:
Porsche 993 C2/C4 3.6L 1996-98
M64.21
M64.22
M64.23
M64.24
Click 'Zoom in' for large parts diagram.
Diagram Ref No 9.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99310540502
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
Sold each
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 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)
This is the standard valve guide used in early air-cooled Porsche 911/930 cylinder heads. It’s a plain (non-hydraulic) guide that locates the valve stem in the head; when worn it causes oil burning, loss of compression and poor valve seating — so they’re commonly replaced whenever heads are rebuilt
- 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)
Diagram Ref No 2 and 2A.
What the part is (technical data / dimensions)
Application:
Porsche 911 / 930 from about 1965–1989 (varies slightly by model and year; early cars both intake & exhaust, later years sometimes exhaust only).
Standard size (typical OE): ID ≈ 9.00 mm, OD ≈ 13.06 mm, length ≈ 51.2 mm.
Why these guides should be replaced
- Valve guides are a wearing item. Replace them when any of the following occur or when you rebuild the engine head.
- Excessive valve stem play — worn guide ID internal diameter lets the valve rock and misalign with the seat , poor sealing, reduced compression and power.
- Oil consumption / smoking — worn guides allow oil to wick down the stem into the combustion chamber, causing blue/grey smoke and fouled plugs.
- Hard starting, rough idle, misfire — poor sealing / valve timing irregularities from misaligned valves.
- Valve wobble that leads to premature valve stem wear or valve seat damage — once stems or seats are damaged you need deeper surgery.
- If a guide is cracked, broken, or has excessive ovality — must be replaced.
- Whenever you remove and refinish seats / replace springs / do a full head rebuild — replacing guides at that time is cheap insurance and ensures correct alignment.
Inner diameter 9,00 mm
Outer diameter 13,06 mm
Total Length 51,20 mm
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93010432100
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)
12 per engine. Price shown is for each.
Fits:
Porsche 911 1965-89
Outer diameter: 13,26 mm,
Bore Ø: 9,00 mm,
Length: 51,20 mm,
Fitting Position: Intake Side
Click 'Zoom in' for large parts diagram.
Diagram Ref No 2.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93010432150
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