Main bearing set, 0.25mm oversize Inner & Outer. Porsche 911 / 964 / 993 / 996 Turbo / GT3 › 96410190171

OE Match main bearing set, both inner and outer specifications are 0.25mm oversize; selection requires confirmation of the engine’s measured dimensions.

Fits

Porsche 911 1978-89
Porsche 964 1989-94
Porsche 993 1994-97
Porsche 996 Turbo 2000-05

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

Diagram ref no: 21

What This Product Does

Main bearing shells support the crankshaft within the crankcase. Working with the engine’s oil supply, they provide the bearing interface and controlled clearance needed for lubricated rotation.

Functions

• Support crankshaft rotation within its housings.
• Distribute loads transmitted through the main journals.
• Provide the specified clearance for lubrication when correctly matched and installed.
  
  

Technical Details

• Supplied reference: 96410190171.
• Component: crankshaft main bearing set.
• Inner specification: 0.25mm oversize.
• Outer specification: 0.25mm oversize.
  
  

Symptoms of Fault

Possible signs warranting inspection include a rumbling or knocking sound, reduced oil pressure when warm, or metal particles found during oil and filter checks. These symptoms do not establish bearing failure on their own.

Why Replacement Matters

Worn shells can affect bearing clearance and expose the crankshaft to further damage. During rebuilding, inspect the journals and crankcase housings, establish the required bearing specification and investigate lubrication or contamination problems before assembly. Vehicle compatibility alone does not confirm that this oversize set suits an individual engine.

FAQs

Which measurements need checking?
Inspect the crankshaft journals and housing bores, then verify assembled clearances against the applicable engine specifications.

What can accelerate bearing deterioration?
Insufficient lubrication, contaminated oil, excessive heat and unsuitable clearances can contribute to wear.

Will worn bearings always make a noise?
No. Changes in oil pressure or inspection findings may appear before an audible knock develops.