Connecting bridge Genuine Porsche part 99310439100

Code: 99310439100

Genuine Porsche part

Connecting bridge

The product code 99310439100 was also found on these diagrams

102-05 - bridge

cylinder with piston 964 1989-94

102-05 - bridge

cylinder with piston 993 1994-98

Additional information:

• This part is brand new and unused.
• Please verify that it is 100% suitable for your specific vehicle before purchase to ensure compatibility.

Before purchasing thoroughly check part to confirm compatibility.

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Inlet valve guide 1st oversize. Porsche 993 1994-98

99310432271/1

Product Information

Exhaust valve guide 1st oversize.
This is a replacement intake valve guide - the small, cylindrical bushing within the cylinder head that guides the intake valve stem, ensuring correct alignment and smooth, controlled movement as the valve opens and closes. In some rebuild or re-machining scenarios, oversized guides are used to restore proper fit after head work.
Price is for each, 6 required per engine.

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.

• Supplied individually - multiple guides needed per head depending on engine (one per intake valve).

This valve guide keeps the intake valve moving in perfect alignment, ensuring proper sealing, efficient combustion, and stable engine performance. It supports the valve stem to prevent wobble or side movement that can cause uneven seat wear or loss of compression. Designed to withstand high RPM and heat, it promotes smooth valve operation and protects the valve, seat, and cylinder-head surfaces. As an oversize guide, it also restores correct fit in worn or re-machined heads, ensuring a safe and reliable rebuild.

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.

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Related, superseded, cross reference or alternative numbers for comparison.

99310432271

99310432271

The product you are viewing cross references to these numbers

5 5 5 5 5

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

99310432271/1KIT

Product Information

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.

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Related, superseded, cross reference or alternative numbers for comparison.

99310432271

99310432271

The product you are viewing cross references to these numbers

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Connecting bridge Genuine Porsche part 99310439100