ACL 4B1236HX-STD Race Rod Bearing Set STD +0.001" Mitsubishi 4B11T Evo X 08-15

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 HX designation indicates extra oil clearance: the bearing wall is approximately 0.013mm thinner per shell compared to the standard 4B1236H-STD set, providing approximately 0.025mm (0.001") of additional running clearance at standard crankshaft journal diameter. This is achieved without any crankshaft grinding - the crankpin remains at stock diameter.
• Recommended for high-performance, high-boost, or high-RPM 4B11T builds where slightly increased oil film thickness is desired for improved bearing protection under elevated cylinder pressures and temperatures.
• For standard oil clearance at stock journal diameter, use 4B1236H-STD. For reground crankshafts, use the appropriate oversize H set: 4B1236H-.025 (+0.025mm) or 4B1236H-.25 (+0.25mm).
• Always confirm actual running clearance with Plastigage or a dial bore gauge after assembly - do not rely solely on bearing size designation.
• 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.
• HX extra-clearance wall thickness provides approximately 0.025mm (0.001") of additional oil clearance versus the H-STD set, increasing oil film volume between the crankpin and bearing surface for improved lubrication under extreme load.
• 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 boost 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: 4B1236HX-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)
• Oil Clearance Designation: HX - Extra +0.025mm (+0.001") clearance vs. H-STD
• 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: approx. 1.487mm (0.0586 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, Extra Oil Clearance (HX)

Product Description

The ACL Race Series 4B1236HX-STD connecting rod bearing set is the extra-clearance performance option for the Mitsubishi 4B11T - the 2.0L DOHC turbocharged four-cylinder engine powering the Lancer Evolution X from 2008 to 2015. Sharing the same standard crankpin journal diameter as the 4B1236H-STD, the HX variant uses a slightly thinner wall (~0.013mm per shell) to deliver approximately 0.025mm (0.001") of additional running oil clearance without any crankshaft modification. This increased clearance supports a thicker hydrodynamic oil film between the crankpin and bearing surface - a meaningful advantage in high-boost, high-temperature, or sustained high-RPM 4B11T applications where the factory clearance can become marginal.

Built on ACL's Race Series tri-metal platform, these bearings deliver superior fatigue resistance, crush, and bearing retention compared to OEM shells. The HX is a popular choice for performance builders who prefer a more liberal oil clearance specification at stock journal size, particularly when running lightweight racing oils or targeting aggressive power levels on modified Evo X engines. Always confirm actual running clearance at assembly. Sold as a complete set of 8 shells for one engine.