ACL 4B1568H-STD Race Rod Bearing Set for 1988-1991 BMW M3 E30 (S14)

Vehicle Fitment

• 1988-1991 BMW M3 (E30), S14 Inline-4 - S14B20 / S14B23 / S14B25

Features

• Race Series connecting rod bearing set for high-performance engines
• Tri-metal construction: copper/lead/tin for superior durability
• No flash-plating - better heat transfer and bearing retention
• Increased eccentricity to improve hydrodynamic oil film formation at high rpm
• Tight wall tolerances for consistent oil clearance
• Enlarged inner-diameter chamfers to clear large crank fillets
• Steel backing for enhanced structural strength under load

Specifications

• Bearing Size: Standard (STD)
• Shaft (Journal) Range: approx. 1.8888 - 1.8894 in / 47.975 - 47.991 mm
• Tunnel (Rod Bore) Range: approx. 2.0472 - 2.0478 in / 52.000 - 52.015 mm
• Maximum Wall Thickness: ~1.993 mm
• Shell Length: ~20.00 mm

Included Components

• 1 x Set of 8 Rod Bearing Shells (4 Upper + 4 Lower)

Product Description

The ACL 4B1568H-STD is a high-performance rod bearing set from the Race Series, specifically tuned for the BMW E30 M3's S14 2.0-2.5L inline-4 engines. This bearing set's tri-metal metallurgy and robust build quality support high rpm and demanding driving conditions, making it perfect for both street-tuned and race builds.

With no flash-plating, these bearings improve thermal conductivity and provide a strong grip on the connecting rod, increasing reliability under stress. The increased eccentricity helps maintain a consistent oil film, which is critical in high-performance operation. Enlarged chamfers accommodate crankshafts with larger fillet radii, while the steel backing ensures structural integrity under high loads.

Designed for the 1988-1991 BMW M3 (E30) equipped with the S14B20, S14B23, or S14B25 engines, these bearings deliver race-grade performance. Correct installation with proper lubrication and torque is essential to maximize bearing life and engine reliability.