Cylinder head exhaust valve kit, SET OF 6. Porsche 911 S / TU / T / E  ❭  90110540850

Cylinder head exhaust valve kit. 
OE Match replacement kit designed for the cylinder heads of classic Porsche 911 S, T, T(U), and E engines. This set provides the correct quantity of exhaust valves required for a complete flat-six cylinder head rebuild.
SET OF 6 exhaust valves

Fits:
Porsche 911 S / TU /T / E - 1965 to 1969
Porsche 914-6 - 1970 to 1976

Diagram ref no 10

Exhaust valves control the release of combustion gases from each cylinder. By opening and closing in precise timing with the camshaft, they allow efficient evacuation of exhaust gases while maintaining proper compression when closed. Replacing all exhaust valves as a set ensures balanced engine performance across all cylinders.

Function: Each exhaust valve seals against the valve seat during combustion, then opens to allow exhaust gases to exit the cylinder. Because exhaust valves operate at significantly higher temperatures than intake valves, correct material quality and precise machining are essential for durability, sealing, and long-term reliability.

Exhaust valves are subject to extreme heat and wear. Over time they can burn, pit, or lose their ability to seal correctly, leading to compression loss, misfires, and reduced engine efficiency. Replacing all six exhaust valves during a rebuild ensures consistent combustion, reliable sealing, and protects newly machined valve seats from premature damage.

When to replace
Replace exhaust valves as a complete set when:
•  Performing a full engine or cylinder head rebuild
•  Leak-down or compression tests indicate valve sealing issues
•  Burnt, pitted, or tuliped valves are found during inspection
•   Valve stem wear exceeds specification
•   Restoring or refreshing a classic 911 engine

Related reference numbers
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90110540850

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