ACL Race Series .25 Main Bearing Set for Nissan VQ35HR/VQ37VHR/VR38DETT - 4M2505H-.25

Construction: High-performance tri-metal bearing material

Bearing Specification: 0.25 mm undersize for rebuild and repair applications

Operating Conditions: Designed to withstand extreme high-RPM operation

Overlay: Reduced-thickness, high-strength overlay for improved fatigue resistance

Steel Backs: Hardened for added stability and bearing retention

Bearing Crush: Increased for secure housing fitment

Surface Finish: No flash plating for improved heat transfer and housing grip

Eccentricity: Optimized to support stable oil-film formation under load

Oil Groove: 3/4-grooved design for balanced load distribution and oil flow

Wall Tolerances: Tight and consistent for precise bearing clearances

Chamfers: Enlarged inside-diameter chamfers for performance crankshaft compatibility

Brand: ACL

Part Number: 4M2505H-.25

Product Series: Race Series

Part Type: Main bearing set

Bearing Size: 0.25 mm undersize

Available Series Sizes: STD and 0.25 mm

Tunnel Diameter: 69.993–70.017 mm

Shaft Diameter: 64.951–64.975 mm

Maximum Wall Thickness: 2.516 mm

Maximum Length: 20 mm

Bearing Halves: Upper and lower

Weight: 0.36 kg

Quantity: 1 set

What's Included: One ACL Race Series main bearing set

ACL Bearings is an Australian manufacturer known for producing precision engine bearings for original-equipment, replacement and high-performance applications. The company has manufactured bearings in Launceston, Tasmania since 1949, developing extensive experience in metallurgy, machining and engine bearing design. ACL’s motorsports involvement dates back to the 1960s, including bearings produced for Brabham Formula 1 engines, and its products have since been used in drag racing, drifting, rally, speedway and touring-car competition. Today, the ACL Race Series is its best-known performance line, offering main bearings, connecting rod bearings, thrust washers and related engine components for a wide range of Japanese, American, European, Australian and Korean engines. This combination of manufacturing history and racing experience has made ACL a trusted choice for professional engine builders and performance enthusiasts.

For Nissan Skyline GT-R and Nissan GT-R applications, ACL offers performance bearing solutions for the RB26DETT used in the R32, R33 and R34 Skyline GT-R, along with the VR38DETT found in the R35 GT-R. ACL Race Series bearings are designed to support stable oil control, accurate bearing clearances and dependable crankshaft operation under the higher cylinder pressures, engine speeds and temperatures produced by modified turbocharged engines. Depending on the application, available features may include tri-metal construction, strengthened overlays, hardened steel backs, optimized oil grooves and tightly controlled wall thicknesses. Select standard-size, undersize and additional-clearance options also give engine builders greater flexibility when setting up an RB26 or VR38 for street, competition or high-horsepower use.

ACL products are covered by the manufacturer’s applicable warranty. All warranty claims are reviewed individually and are subject to inspection and approval by ACL.

To begin a claim, please contact Elite GT-R Parts with:

• Your order number and ACL part number
  
• A description of the problem
  
• Clear photos of the product and affected components
  
• Any requested installation or engine-build information
  

Please do not return or ship the product until return instructions have been provided. Additional documentation or inspection may be required before ACL can make a decision. Final warranty eligibility and the available resolution are determined by ACL according to its current warranty terms.