Engine Valves / Guides / Springs

Valve spring kit - high performance. 

Fits:
Porsche 911 - 1965 to 1989
Porsche 964 - 1989 to 1994
Porsche 993 - 1994 to 1998

Our Valve Springs are designed and manufactured to specifically fit the envelope of a Porsche application not a spring from another use. 

It operates a higher natural frequency than the original spring for racing and at the very least minimizes damage from over rev in track day situations. 

Please note
993 - must use 8mm Ti retainers and Aasco Seats

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Related, superseded, cross reference or alternative numbers for comparison.

HP109

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9mm Titanium valve spring retainer disc kit - high performance. 

Fits:
Porsche 911 - 1965 to 1989
Porsche 964 - 1989 to 1994

9mm Porsche 911 titanium valve spring retainers for 9mm valves. 

Can be used to directly replace OE retainers but we recommend using in conjunction with Aasco HP109  valve springs and HPSS spring seats.

Set of 12

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HP10T9

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Valve spring seat inlet and exhaust. 

Sold each - 12 per car

Fits:
Porsche 911 - 1965 to 1989
Porsche 911 turbo - 1975 to 1989
Porsche 964 - 1989 to 1994
Porsche 914/6 - 1970 to 1976

Click 'Zoom in' for large parts diagram.
Diagram ref no 14

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90110542104

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Valve spring seat kit - high performance. 

Fits:
Porsche 911 - 1965 to 1989
Porsche 964 - 1989 to 1994
Porsche 993 - 1994 to 1998

Our Steel Spring Seats pocket the inner spring of our Aasco High Performance Valve Springs.

Our Valve Springs are designed and manufactured to specifically fit the envelope of a Porsche application not a spring from another use. 

It operates a higher natural frequency than the original spring for racing and at the very least minimizes damage from over rev in track day situations. 

Please note
993 - must use 8mm Ti retainers and Aasco Seats

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Related, superseded, cross reference or alternative numbers for comparison.

HPSS

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Valve spring.
This spring pair fits all 911's from 1965 to 1994.

Fits:
Porsche 911 1965-89
Porsche 964 1989-94

Click 'Zoom in' for large parts diagram.
Diagram Ref No 13.

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90110590151

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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.

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90110590151

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OE Match valve stem seals control oil flow between the valve stems and guides. They are replacement sealing components for cylinder-head repairs and engine rebuilding work.

Supplied each.

Fits

• Porsche 911 1968-89 (12 Per Engine)
• Porsche 924S (8 Per Engine)
• Porsche 944 (8 Per Engine)
• Porsche 944 2.7L (8 Per Engine)
• Porsche 964 3.6L (12 Per Engine)
• Porsche 964 Turbo (12 Per Engine)
• Porsche 928 (16 Per Engine)
  
  Check fitment for your specific vehicle (model, year, engine) before ordering.
  
  Diagram ref no 19
  
  What Is This Part?

A valve stem seal is a small sealing component fitted around a valve stem at the valve guide in the cylinder head. It meters the oil reaching the sliding stem-to-guide contact, allowing lubrication while restricting excess oil from passing into the engine's gas passages. The seal works alongside the valve and guide, so their condition matters to successful sealing. During cylinder-head work, the seals should be assessed together with valve-stem and guide wear rather than treated as an isolated cure for oil consumption.

What Does This Part Do?

• Meters lubricating oil: Controls the amount of oil reaching the valve stem and guide contact.
• Restricts excess oil: Helps limit oil passing down the valve guide towards the inlet or exhaust passage.
• Seals around a moving stem: Maintains its sealing contact as the valve opens and closes.
  
  Why Replace This Part?

A damaged sealing lip or a seal that no longer seats correctly can allow too much oil past the valve guide. Replacement is appropriate when inspection identifies deterioration, damage or leakage at this point, including damage sustained during dismantling or installation.

Worn guides can allow excessive sideways valve movement and prevent a replacement seal from controlling oil correctly. Check guide clearance and valve-stem condition during repairs; fitting seals alone will not correct mechanical wear in those components.

When to Replace This Part?

• Visible damage: Replace a seal with a torn lip, cracking or other deterioration found during inspection.
• Poor seating: Investigate seals that are displaced or no longer retained correctly on the guide.
• Oil consumption or blue exhaust smoke: Inspect the seals and guides as possible causes, while checking other sources of oil burning.
• Valve-guide repairs: Assess the seals when valves or guides are removed and renew those damaged or unsuitable for refitting.
• Installation damage: Replace any seal whose lip has been cut or distorted while passing over the valve-stem grooves.
  
  Where Is This Part Fitted?

Location: In the cylinder head, around the valve stem at the upper end of the valve guide, within the valve-spring area.

FAQs

• Can I replace only the valve stem seals?
  Yes, if inspection confirms the seals are responsible and the valves and guides remain serviceable. Excessive guide clearance needs separate attention.
• Does exhaust smoke always mean these seals need replacing?
  No. Smoke and oil consumption can have several causes. Confirm the source before deciding on seal replacement or more extensive engine work.
• What matters during installation?
  Follow the engine-specific procedure, protect the sealing lip from the valve-stem grooves and use the appropriate fitting tool to seat the seal without damage.
  
  Product Summary

• Product: Valve stem seals.
• Brand: OE Match.
• Supply: Each.
• Purpose: Controls oil flow at the valve stem and guide.
• Repair context: Cylinder-head sealing repairs and engine rebuilding.

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

96410411107

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Valve stem seals. Price shown is for each.

Fits:
Porsche 911 1968-89 (12 Per Engine)
Porsche 924S (8 Per Engine)
Porsche 944 (8 Per Engine)
Porsche 944 2.7L (8 Per Engine)
Porsche 964 3.6L (12 Per Engine)
Porsche 964 Turbo (12 Per Engine)
Porsche 928 (16 Per Engine)

Click 'Zoom in' for large parts diagram.
Diagram Ref No 19.

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

96410411107

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