Exhaust valve guide 1st oversize, SET OF 6. Porsche 993 1994-98  ❭  99310432172

Exhaust valve guide - 1st oversize - set.
This is a set of six OE Match quality exhaust valve guides designed for the air-cooled Porsche 911 (993) engines produced between 1994 and 1998. These are 1st oversize valve guides, meaning they are slightly larger than standard guides to accommodate engines that have been reamed or show wear in the original guide bores. The set contains six guides, enough for a full cylinder head rebuild on the exhaust side.
SET OF 6

Fits:
Porsche 993 1994 - 1998

Diagram Ref no 2.

Valve guides are precision metal bushings pressed into the cylinder head that support and guide the movement of the exhaust valve stems. Over time, original guides can wear, allowing excessive valve stem play, reducing seal effectiveness, and increasing engine oil consumption. These OE Match valve guides are manufactured to match Porsche’s original specifications, including diameter, material quality and machining tolerance, but in a 1st oversize dimension so they fit reamed cylinder heads.

This SET OF 6 provides a complete set for one engine’s exhaust side - ideal for cylinder-head rebuilds, valve jobs or whenever the exhaust guide bores are undersized due to wear.

The exhaust valve guides:
•  Support and align the exhaust valve stems so they travel accurately within the head.
•  Maintain correct valve seating and combustion sealing, which is vital for performance and compression.
•  Help conduct and dissipate heat from valves into the cylinder head casting.
•  Reduce lateral valve stem movement, decreasing wear on stems and valve seats.

By replacing old or worn guides with a matched oversize set, you can restore tight tolerances in the valve train and help ensure efficient combustion and long-term reliability.

Valve guides wear over time due to heat, friction, and repeated valve movement. When guides become worn or oversized gaps develop between the valve stem and guide bore, the following issues can arise:
•  Loss of performance and power
•  Higher oil consumption
•  Reduced sealing and compression
•  Increased valve train wear

Installing a correct OE Match valve guide restores correct valve alignment, reduces unwanted movement, supports proper seat sealing, and prolongs the life of your engine’s top end - especially in rebuild or high-mileage applications.

Replace valve guides if you observe:
•  Blue smoke from the exhaust (signifying oil burning)
•  Rough idle or hesitation
•  Poor compression or loss of engine power
•  Valve stem play when checked during teardown
•  During a cylinder head rebuild or valve job

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99310432172

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