ACL 7M2394HX-STD Race Series Main Bearings STD +.001" for Nissan RB20/25

Vehicle Fitment

• 1989-1994 Nissan Skyline R32 GTS (2.0L RB20E, RB20DE)
• 1989-1994 Nissan Skyline R32 GTS-t (2.0L RB20DET)
• 1993-1998 Nissan Skyline R33 GTS (2.0L RB20E, RB20DE)
• 1993-1998 Nissan Skyline R33 GTS25 (2.5L RB25DE)
• 1993-1998 Nissan Skyline R33 GTS25-t (2.5L RB25DET)
• 1999-2002 Nissan Skyline R34 25GT (2.5L RB25DE NEO)
• 1999-2002 Nissan Skyline R34 25GT-t (2.5L RB25DET NEO)
• 1985-2004 Nissan Patrol Y60/Y61 (3.0L RB30E, RB30ET)
• 1986-2004 Nissan Safari Y60/Y61 (2.8L RD28, RD28E, RD28T, RD28Ti)

Features

• HX Series design is .0005 inches (.0127mm) thinner per half for .001 inches total extra clearance
• Tri-metal construction with hardened steel backing withstands high RPM, high stress loads, and extreme temperatures
• High strength overlay with reduced thickness for improved fatigue strength and seizure resistance
• Large chamfer accommodates larger crankshaft fillets for high-performance applications
• 3/4 groove design provides optimum oil supply to connecting rods while maximizing load carrying capacity
• Increased crush and tighter wall tolerance ensures better seating and consistent oil clearances
• Micron tolerance machining delivers consistent accuracy to wall thickness and crush specifications
• No flash plating applied to maximize heat transfer and improve bearing retention

Specifications

• Part Number: 7M2394HX-STD
• Bearing Size: STD (Standard) with HX clearance
• Bearing Half Type: Upper and Lower
• Bearing Material: F780 tri-metal with hardened steel backing
• Max Overall Length: 19.12mm (0.753 inches)
• Max Shaft Size: 54.975mm (2.164 inches)
• Min Shaft Size: 54.951mm (2.163 inches)
• Max Tunnel Size: 58.658mm (2.309 inches)
• Min Tunnel Size: 58.645mm (2.309 inches)
• Max Vertical Oil Clearance: 0.095mm (0.0037 inches)
• Min Vertical Oil Clearance: 0.042mm (0.0017 inches)
• Max Wall at Crown: 1.814mm (0.071 inches)
• Quantity: Set of 14 bearing halves (7 main bearings)

Included Components

• 14x Bearing halves (7 complete main bearing sets)

Product Description

The ACL 7M2394HX-STD Race Series Main Bearings deliver professional-grade performance for Nissan RB20, RB25, and RB30 inline-six engines. Engineered specifically for high-performance street builds and dedicated track machines, these bearings feature ACL's advanced tri-metal construction with a hardened steel backing that maintains crush under extreme loads and temperatures. The HX designation indicates these bearings are manufactured .0005 inches (.0127mm) thinner per half compared to standard ACL Race bearings, providing an additional .001 inches (.0254mm) of total oil clearance for standard-sized crankshafts. This extra clearance is a popular preference for performance builds as it accommodates slight variations in machining tolerances and allows for better oil flow under high-RPM conditions, reducing the risk of bearing failure due to insufficient clearance.

ACL's proprietary F780 tri-metal material blend combines high strength with excellent seizure resistance, while the improved overlay with reduced thickness dramatically improves fatigue strength compared to OEM bearings. The 3/4 groove design ensures optimum oil supply flows to the connecting rod bearings while maintaining maximum load-carrying capacity across the bearing surface. Large chamfers accommodate the larger crankshaft fillets commonly found in performance-machined cranks, while increased crush and tighter wall tolerances ensure consistent seating in the block's main journals. Unlike many aftermarket bearings, ACL applies no flash plating to further improve bearing retention and maximize heat transfer away from the crankshaft journals. Micron-tolerance CNC machining supported by precision measurement systems delivers consistent accuracy to critical characteristics like wall thickness and crush, ensuring reliable fit and helping maintain consistent oil clearances throughout the engine's operating range.

This bearing set fits a wide range of Nissan applications including Skyline R32, R33, and R34 models equipped with RB20E, RB20DE, RB20DET, RB25DE, RB25DET, and RB25DET NEO engines, as well as Patrol and Safari trucks with RB30E, RB30ET, RD28, RD28E, RD28T, and RD28Ti engines. The set includes all 14 bearing halves required for a complete main bearing installation (7 main journals). Important note: Always consult with your machine shop or engine builder before purchasing bearings to determine which size and clearance would be optimal for your specific application, bore/stroke combination, and intended use. ACL recommends measuring your crankshaft journals and block main saddles to ensure proper fitment and oil clearance. These bearings are designed for engines being built for performance use, whether naturally aspirated or turbocharged, and are suitable for street, drag racing, circuit racing, drift, and time attack applications. With over 25 years of motorsport heritage including Formula 1, Australian Supercars, and numerous championship wins worldwide, ACL bearings represent the perfect upgrade for any serious RB-series engine build.