ACL 4B1236H-STD Race Rod Bearing Set Standard 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

• Standard (STD) crankshaft rod journal diameter - for use with stock or unworn crankpins at factory diameter only. Do NOT use on reground crankshafts; use 4B1236H-.025 for crankpins ground 0.025mm undersize, or 4B1236H-.25 for crankpins ground 0.25mm undersize.
• An HX extra-clearance variant (4B1236HX-STD) is also available for builders targeting a looser running clearance at standard journal diameter - the HX wall is approximately 0.013mm thinner per shell, yielding approximately 0.025mm (0.001") additional oil clearance.
• 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 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-STD
• Product Line: ACL Race Series
• Application: Connecting Rod Bearings
• Engine Compatibility: Mitsubishi 4B11T 2.0L DOHC Turbo Inline-4
• Crankshaft Size: Standard (STD - Unground)
• 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 - Standard Size

Product Description

The ACL Race Series 4B1236H-STD connecting rod bearing set is the standard-size performance replacement 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. Designed for use with stock-diameter, unground crankshaft rod journals, this is the most common selection for fresh engine builds using a serviceable factory crank, as well as for performance rebuilds where the crankshaft has been inspected and confirmed to be within standard dimensional tolerance.

Built on ACL's Race Series tri-metal platform, these bearings deliver meaningfully superior fatigue resistance, crush, and oil film stability compared to OEM Mitsubishi shells - making them a standard upgrade in any serious 4B11T build, from mild street rebuilds to full-boost competition engines. For builders targeting increased running clearance at standard journal size, the HX variant (4B1236HX-STD) is available separately. Always confirm clearances at assembly with precision measurement before final torque. Sold as a complete set of 8 shells for one engine.