Inlet valve guide 1st oversize, SET OF 6. Porsche 993 1994-98  ❭  99310432271

Exhaust valve guide 1st oversize.
This set of 6 intake valve guides (1st oversize) is designed for professional cylinder-head rebuilds on Porsche 993 air-cooled flat-six engines. Manufactured to match original Porsche dimensions, material specifications, and hardness ratings, these guides ensure the intake valves operate with correct alignment, stability, and sealing performance - all essential for maintaining proper combustion and long-term engine reliability.
SET OF 6

Fits:
Porsche 993 1994 - 1998

Diagram Ref no 3.

• Use Cases: Head rebuilds; valve-seat re-cut; restoring compressed guide bores; upgrading worn or damaged valve guides; preventive maintenance where valve guide integrity is uncertain.

Oversize valve guides are used when the cylinder-head guide bores have worn or been machined during refurbishment. This set provides a complete, matched group of intake guides, ensuring uniform fitment and valve control across all cylinders. With precision-machined tolerances and excellent heat resistance, these OE-match guides restore the valve train to factory behaviour, eliminating excessive valve play and preventing compression loss, misfires or premature wear.

Perfect for engine rebuilders, restorers, and anyone refreshing a 993 cylinder head, this set supports smooth, accurate valve movement and optimal sealing under the high temperatures and RPM conditions typical of Porsche’s air-cooled performance engines.

Valve guides endure constant thermal cycles, valve-spring force, and high-speed motion. Over time they can wear, enlarge, or become loose - causing:
• Valve wobble and mis-alignment
• Poor sealing at valve seats - resulting in compression loss, misfires, or exhaust leakage
• Increased valve-stem wear, potential seat damage, or premature engine wear
• Reduced engine efficiency, elevated emissions, and unsafe reliability.

Replacing worn or oversized guides with a proper unit restores correct valve operation, extends cylinder-head life, ensures compression integrity, and brings the engine back to spec - critical for performance, reliability, and longevity.



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