ACL bearings are used for tuning and engine upgrades where you want better quality with higher bearing capacity than normal standard bearings. Improvements of material, dynamic thickness, heat conduction, oil grooves and oil distribution are some of the points that make ACL one of the leading bearing manufacturers. Bearing data Part number: 4B1956H Bearing size: .25 Bearing half type: Identical halves Bearing material: F781 Technical data (mm) Max overall length: 18.5 Max shaft size: 45 Max tunnel size: 48.02 Max vertical oil clearance: 0.108 Max wall at crown: 1.499 Min shaft size: 44.98 Min tunnel size: 48 Min vertical oil clearance: 0.049 Technical data (in) Max overall length: 0.728345007 Max shaft size: 1.771650016 Max tunnel size: 1.890547417 Max vertical oil clearance: 0.00425196 Max wall at crown: 0.059015631 Min shaft size: 1.770862616 Min tunnel size: 1.889760017 Min vertical oil clearance: 0.00192913 Engine code B18A (USA) / B20B4 / B20Z2 / D15B1 / D15B2 / D15B4 / D15B6 / D1