ACL 4B1236H-.025 Race Rod Bearing Set +0.025mm Mitsubishi 4B11T Evo X 2008-2015

Vehicle Fitment

• 2008-2015 Mitsubishi Lancer Evolution X (Evo X) - GSR, MR, SE, Final Edition (2.0L 4B11T DOHC Turbo Inline-4)

Fitment Notes

• The .025 suffix designates this as the +0.025mm oversize bearing set - intended for use when the crankshaft rod journals have been ground 0.025mm undersize during a rebuild. The bearing wall is correspondingly thicker to restore the correct running oil clearance on a lightly reground crankshaft.
• Do NOT use this set on a stock, unground crankshaft - the thicker wall will produce excessive interference and critically tight oil clearance. For standard (unground) crankpins, use 4B1236H-STD. For +0.25mm reground crankpins, use 4B1236H-.25.
• Always measure crankshaft rod journal diameter with a micrometer before selecting bearing size. Confirm actual clearance with Plastigage or a dial bore gauge after assembly.
• Sold as a complete set of 8 bearing shells - sufficient for one full 4-cylinder engine build.

Features

• Tri-metal construction: copper-lead alloy lining bonded over a hardened steel backing, with a high-strength overlay plate - engineered for the sustained high-boost, high-RPM demands of built and modified 4B11T applications.
• Hardened steel backing on all rod bearings improves structural support of the bearing lining and maintains crush under high sustained loads - especially important in the 4B11T's aluminum block under elevated cylinder pressures.
• High-strength overlay plate with reduced thickness provides improved fatigue resistance compared to OEM-spec bearings - critical in high-boost Evo X builds where rod bearing loads are significantly above stock.
• Increased bearing crush and tighter wall tolerances ensure consistent, secure seating in the connecting rod bore, reducing the risk of bearing spin.
• Enlarged ID chamfers on bearing edges accommodate the larger fillet radii found on aftermarket and performance-ground 4B11T crankshafts.
• 3/4-groove design optimizes oil supply to the rod journal and maximizes load-carrying surface area across the bearing face.
• Elimination of flash plating on bearing backs improves heat transfer and maximizes grip between the bearing shell and the rod housing bore.
• Increased eccentricity compensates for bore distortion at high RPM and assists in the formation of a stable hydrodynamic oil film under load.

Specifications

• Part Number: 4B1236H-.025
• Product Line: ACL Race Series
• Application: Connecting Rod Bearings
• Engine Compatibility: Mitsubishi 4B11T 2.0L DOHC Turbo Inline-4
• Crankshaft Size: +0.025mm Oversize (for crankpins ground 0.025mm undersize)
• Shaft (Crankpin) Diameter: 51.954-51.972mm (2.0454-2.0461 in)
• Tunnel (Housing Bore): 55.000-55.010mm (2.1654-2.1657 in)
• Maximum Wall Thickness at Crown: 1.500mm (0.0591 in)
• Maximum Overall Length: 17.00mm (0.669 in)
• Bearing Material: Tri-Metal Copper-Lead Alloy / Hardened Steel Backing
• Quantity: Set of 8 Shells (complete engine set)

Included Components

• 8x Race Series Connecting Rod Bearing Shells - +0.025mm Oversize

Product Description

The ACL Race Series 4B1236H-.025 connecting rod bearing set is the +0.025mm oversize option for the Mitsubishi 4B11T - the 2.0L DOHC turbocharged four-cylinder engine that powered every generation of the Lancer Evolution X from 2008 to 2015. This oversize set is selected when the crankshaft rod journals have been lightly reground 0.025mm undersize to clean up surface damage or restore proper geometry during a rebuild. The thicker-walled bearing shell compensates precisely for the reduced crankpin diameter, restoring factory-spec oil clearance on the ground crank.

Built on ACL's Race Series tri-metal platform, these bearings offer superior fatigue resistance, bearing retention, and oil film stability compared to OEM shells - a critical upgrade for any high-boost or high-RPM 4B11T build where the stock copper-lead overlay is the first point of failure. Always verify crankshaft journal diameter with precision measuring equipment and confirm clearances at assembly before final torque. Sold as a complete set of 8 shells for one engine.