Selection of engine bearing materials

Dr. Dmitri Kopeliovich

Selection of bearing material suitable for a particular engine should be based on the following engine parameters:

• Maximum specific load applied to the bearing. The bearing load capacity (fatigue strength) should be higher than the maximum specific load. A safety factor of at least 10-15% should be taken into account.
• Crankshaft material. Nodular (ductile) cast iron shafts have a rough surface resulting from the cast iron microstructure. Such rough surface causes increased wear of soft overlays of tri-metal bearings. AlSi bearings are more compatible to nodular cast iron crankshafts. Tri-metal bearings are recommended for steel crankshafts.
• Possible misalignments and distortions. Aluminum bearings are more tolerant to misalignments and distortions due to the greater thickness of the bearing layer (~0.01”/0.25mm). Tri-metal bearings with Babbitt overlay (thickness 0.0008”/0.02mm) are more sensitive to geometric defects.
• Minimum oil film thickness. The value of this parameter is not always known however it is important for proper selection of the bearing material. If the minimum oil film thickness is 0.000040-0.000060” (1-1.5µm) or lower, mixed lubrication regime occurs frequently and tri-metal bearings with soft thin overlays are less suitable than aluminum-silicon bearings.

Stock engines, street performance and circle track racing engines may use conventional aluminum-tin-silicon bi-metal or copper based tri-metal bearings depending on the load and crankshaft materials (AlSi bi-metal – for nodular cast iron shafts, tri-metal - for forged steel shafts).

Tri-metal bearings are recommended for off-road and off-shore racing engines (typically higher loaded applications).

High strength tri-metal materials (e.g. Sputter bearings) are recommended for applications with high bearing loading where conventional tri-metal material undergoes fatigue (for example upper conrod bearings in diesel engines with direct fuel injection).

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• Bearings in internal combustion engines
• Engine parameters determining bearing loading
• Lubrication regimes
• Hydrodynamic journal bearing
• Hydrodynamic lubrication theory
• Geometrical parameters of engine bearings
• Mechanisms of wear
• Requirements to engine bearing materials
• Engine bearing fatigue test
• Engine bearing materials
• Copper based bearing materials
• Manufacturing bi-metal strips for copper bearings
• Aluminum based bearing materials
• Continuous casting of aluminum based bearing alloys
• Manufacturing bi-metal strips for aluminum bearings
• Lead based engine bearing overlays
• Tin based engine bearing overlays
• Sputter bearing overlays
• Polymer based engine bearing overlays
• Engine bearing failure
• Effect of low viscosity oils on engine bearings
• pMax Black™ - Strengthened Tri-metal Bearing Materials for High Performance Bearings
• U-Groove™ Modified Design of Oil Groove for High Performance Bearings
• ElliptiX™ Oil Hole of New Design for High Performance Bearings
• EccentriX™ Optimal Eccentricity for High Performance Bearings
• RadiaLock™ - Design of Crush Height for Reliable Press Fit of High Performance Bearings
• Modern Trends In Materials For High Performance Engine Bearings
• Optimization of Clearance Design for High Performance Engine Bearings
• Camshaft Bearings
• Ecological Aspects Of Engine Bearings
• Consistency in Bearing Wall Thickness
• Soft Strength of Racing Bearings
• Effect of oil viscosity on hydrodynamic friction of engine bearings
• Bearing Materials For Race Engines
• Oil Clearance and Engine Bearings
• Polymer Coated Bearings
• Development of Performance Bearings for Race Engines of Modern Design
• Polymer Coatings for Race Engine Bearings
• Heavy Duty Engine Bearings - Materials, Geometry, Failures
• Failures of Engine Bearings and their Prevention
• Engine Bearing Housing and How it Affects Engine Bearings
• Hydrodynamic Bearing – Calculations and Design
• Geometry of Engine Bearings
• Crush Height of Engine Bearings
• Materials for Engine Bearings

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