Exhaust valve guide 1st oversize. Porsche 993 1994-98  ❭  99310432172

Exhaust valve guide 1st oversize.
OE Match Exhaust Valve Guide is a precision-engineered valve guide designed to replace the original exhaust valve guide in the Porsche 911 (993) engine. This is a 1st oversize guide - meaning it is slightly larger than standard to accommodate engines that have been reamed or experienced wear over time.
Price is for each, 6 required per engine.

Fits:
Porsche 993 1994 - 1998

Diagram Ref no 2.

This exhaust valve guide keeps the exhaust valve stem perfectly aligned in the cylinder head, helping to ensure the valve seals correctly against the seat, maintains good compression, and promotes efficient evacuation of exhaust gases. A proper valve guide also helps conduct heat away from the valve stem into the head where it can be cooled by the engine’s coolant system.

Function:
• Valve Alignment: Ensures the exhaust valve travels straight and seats accurately each cycle.
• Wear Control: Reduces valve stem wobble and limits side loading that can damage seats or stems.
• Heat Conduction: Helps transfer combustion heat away from the valve stem and into the head casting.
• Rebuild Support: Oversize version is ideal for heads that have been reamed during rebuilds to restore correct fitment.

Fitment
•  Installed in the exhaust sides of the cylinder head valve train
•  Typically 6 guides per engine are needed for a full head rebuild.
•  This part matches Porsche’s oversize guide specification and is used when the standard guide bores have been worked to remove wear or damage.

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

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Related, superseded, cross reference or alternative numbers for comparison.

99310432172

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