Engine Bearings / Shells

Fits:
Porsche 911 - 1965 to 1989
Porsche 914/6 - 1970 to 1976
Porsche 964 - 1989 to 1994
Porsche 993 - 1994 to 1998
Porsche 996 turbo / GT2 / GT3
Porsche 997.1 turbo / GT2 / GT3
Porsche 997.2 GT2 / GT3

This product supersedes Porsche's old part numbers:
- 91610113700
- 99310113700
- 99310113701

Diagram ref no 29.

These high-quality bearings resist wear, maintain stability under loading, and reduce friction. The shoulder shell is designed to handle axial load and keep the shaft from shifting. Both shells are matched to OE tolerances for crush and thickness to preserve ideal oil film clearance and ensure long life.

•  Location: Inside the engine case, at the intermediate shaft bore, flanking the connecting housing
•  Function: Provides radial support and axial control (shoulder shell) for the intermediate shaft

Over time, the intermediate shaft bearing shells may wear, lose geometry, or develop surface fatigue. Symptoms of failure include increased endplay (shaft axial movement), chain rattle, timing variation, and rapid wear of adjacent sprockets or tensioners.

This pair should be replaced during any engine rebuild, crankshaft pull, or when measurements show endplay outside specification. Installing fresh shells restores proper shaft location and timing stability for durable performance.

OE Match big end conrod bearings for Porsche 993 and 996 Turbo applications, supplied as a SET OF 12 in the Oversize 0.25mm specification. These replacement shells are intended for correctly measured engine rebuilding work.

Fits

Porsche 993 1994-98

Check fitment for your specific vehicle (model, year, engine) before ordering.

Diagram ref no: 15

What This Product Does

The bearing shells sit within the connecting-rod big ends, forming the lubricated interface with the crankshaft journals. Correctly selected bearings support rod movement and distribute combustion loads while maintaining the oil clearance required by the engine specification.

Functions

• Provide a bearing surface between each connecting rod and its crankshaft journal.
• Support lubricated movement at the big-end connection.
• Distribute loads transmitted through the connecting rods.
  
  

Technical Details

• Brand: OE Match.
• Product reference retained from the supplied information: 71-3775/6.
• Connecting-rod bearing reference: 99310314753.
• Specification: Oversize 0.25mm.
• Contents: SET OF 12 bearing shells.
  
  

Symptoms of Fault

• A deep knock or rumble, particularly when the engine is loaded.
• Oil-pressure warnings or pressure falling as the engine warms.
• Metal particles discovered during oil or filter inspection.
• Scoring or uneven wear found on dismantled bearing surfaces.
  
  

These findings require diagnosis; none identifies a bearing fault conclusively on its own.

Why Replacement Matters

Renewing worn shells during an engine rebuild allows the builder to establish suitable bearing clearances and inspect the crankshaft and rods for associated damage. Any underlying lubrication problem, contamination or overheating must also be investigated rather than addressed by bearing replacement alone.

FAQs

Can these be selected by vehicle model alone?
No. The listed application must be checked alongside the measured crankshaft journals and the required bearing specification. Oversize 0.25mm must not be assumed suitable for every rebuild.

What needs checking before installation?
Inspect the journals and connecting rods, measure the assembled clearances and investigate the cause of existing wear. A competent engine builder should confirm the final selection.

Does low oil pressure always mean worn bearings?
No. It is a reason to investigate the lubrication system and internal condition, not proof that these shells require replacement.