King CR4507XP XP pMax Black Rod Bearings for Mazda MZR/Ford Duratec 2.3L NA

Vehicle Fitment

• 2002-2008 Mazda 6 (GG/GY, L3-VE MZR 2.3L DOHC 16v, Naturally Aspirated, FWD)
• 2004-2009 Mazda 3 / 3s - excluding Mazdaspeed 3 (BK, L3-VE MZR 2.3L DOHC 16v, Naturally Aspirated, FWD)
• 2004-2010 Mazda 5 / Premacy (CR, L3-VE MZR 2.3L DOHC 16v, Naturally Aspirated, FWD)
• 2001-2005 Mazda Tribute (EP, L3-VE MZR 2.3L DOHC 16v, Naturally Aspirated, FWD/AWD)
• 2001-2011 Mazda B2300 (L3-DE/L3-NS MZR 2.3L DOHC 16v, Naturally Aspirated, RWD)
• 2003-2007 Ford Focus (L3, Duratec 23EW 2.3L DOHC 16v, Naturally Aspirated, FWD)
• 2001-2011 Ford Ranger (Duratec 23NS 2.3L DOHC 16v, Naturally Aspirated, RWD/4WD)
• 2005-2008 Ford Escape (Duratec 23EW 2.3L DOHC 16v, Naturally Aspirated, FWD/AWD)
• 2006-2009 Ford Fusion (Duratec 23EW 2.3L DOHC 16v, Naturally Aspirated, FWD)
• 2005-2008 Mercury Mariner (Duratec 23EW 2.3L DOHC 16v, Naturally Aspirated, FWD/AWD)
• 2006-2009 Mercury Milan (Duratec 23EW 2.3L DOHC 16v, Naturally Aspirated, FWD)

Fitment Notes

• CR4507XP fits the naturally aspirated (non-turbo) 2.3L MZR/Duratec 23 only. It does not fit the turbocharged L3-VDT engine found in the Mazdaspeed 3 (2007-2013), Mazdaspeed 6 (2006), or Mazda CX-7 (2007-2012) - those applications require King CR4604XP.
• CR4507XP is sold as a set of 4 pairs, covering all 4 cylinders of the inline-4 engine in one purchase.
• Size is Standard (STD); intended for engines with crankshaft rod journals at factory specification. Measure journals before ordering - if journals have been machined, select the appropriate undersize variant (CR4507XP.026 or other available undersizes).
• The Ford Ranger and Mazda B2300 use the longitudinally mounted RWD/4WD variant of this engine (L3-NS/L3-DE); rod journal dimensions are confirmed shared with the transverse FWD versions.
• Does not fit the Ford EcoBoost 2.0L or 2.3L turbocharged engines - those are derived from the Duratec platform but use different internal specifications and require CR4604XP.

Features

• King XP-Series pMax Black™ tri-metal construction - the bearing overlay is processed through King's proprietary nano-scaled SecureBond hardening process, producing a fatigue-resistant black shield that is 24% harder than conventional tri-metal race bearing overlays (14.5 Hv vs. 11.5 Hv).
• Enhanced intermediate copper-lead layer with 4.5% tin content and a nickel barrier plate - 22% harder than a standard intermediate layer (115 Hv vs. 90-95 Hv) - delivering a load capacity of 17,000 psi for sustained high-load operation.
• pMax Black™ overlay contains 5% copper and achieves a load capacity of 10,200 psi - substantially exceeding the 8,000-8,500 psi rating of conventional high-performance bearing overlays.
• Narrowed bearing design on the crank cheek side reduces parasitic friction and provides clearance for large-radius fillet crankshaft geometry common on aftermarket forged cranks.
• RadiaLock™ increased crush height improves bearing-to-bore contact surface area, enhances heat transfer from the bearing shell to the connecting rod housing, and significantly reduces bearing spin risk under high-RPM conditions.
• King Bull's Eye Tolerance™ Technology maintains wall thickness variation of ±0.0025 mm (±0.0001 in) shell-to-shell - the tightest tolerance standard in the engine bearing industry - for precise, consistent oil clearance during assembly.
• EccentriX™ medium eccentricity profile - derived from elasto-hydrodynamic analysis and dynamic load calculations - optimizes oil film distribution across the bearing surface and improves lubrication under varying load cycles.
• Engineered specifically for performance and racing applications utilizing forged steel aftermarket crankshafts, where high loads must be sustained for extended periods - suitable for circle track, drag, off-shore, and high-output street builds.
• Produced entirely in-house under King's multi-checkpoint quality control process, ensuring every shell meets dimensional and material specifications before shipment.

Specifications

• Part Number: CR4507XP
• UPC: 611500556418
• Series: XP (Xtreme Performance) - pMax Black™
• Bearing Type: Connecting Rod (Big End) Bearing Set
• Engine Compatibility: Mazda MZR 2.3L 16V (L3-VE, L3-DE, L3-NS) / Ford Duratec 23 2.3L 16V - Naturally Aspirated Only
• Engine Configuration: Inline-4 Cylinder, DOHC, 16-Valve, Naturally Aspirated Gasoline
• Undersize: Standard (STD)
• Overlay Material: pMax Black™ - copper-lead/tin Babbitt with nano-scaled SecureBond hardening
• Intermediate Layer: Copper-lead with 4.5% tin content and nickel barrier plate
• Backing: Steel
• Intermediate Layer Load Capacity: 17,000 psi
• Overlay Load Capacity: 10,200 psi
• Wall Thickness Tolerance: ±0.0025 mm (±0.0001 in)
• Position: Connecting Rod Big End (all 4 cylinders)

Included Components

• 4x Pairs of connecting rod bearing shells (upper and lower, covering all 4 cylinders)

Product Description

The King CR4507XP is a Standard (STD) size XP-Series pMax Black™ connecting rod bearing set engineered for the naturally aspirated Mazda MZR 2.3L and Ford Duratec 23 2.3L inline-four engine family. This includes the Mazda L3-VE, L3-DE, and L3-NS engine codes used across a broad range of Mazda and Ford vehicles produced from 2001 through 2011 - spanning the Mazda 3, Mazda 5, Mazda 6, Mazda B2300, Mazda Tribute, Ford Ranger, Ford Focus, Ford Escape, Ford Fusion, Mercury Mariner, and Mercury Milan. Builders should note that this part number is specifically for the non-turbocharged variant of the 2.3L engine. The turbocharged L3-VDT used in the Mazdaspeed 3, Mazdaspeed 6, and Mazda CX-7 is a distinct application requiring King CR4604XP instead.

The XP-Series pMax Black™ bearing construction represents King's flagship race bearing technology. The intermediate copper-lead layer features an elevated tin content of 4.5% - processed through King's SecureBond nano-scaled hardening method - resulting in a layer that is 22% harder than a conventional intermediate (115 Hv vs. 90-95 Hv) and rated to 17,000 psi load capacity. The pMax Black™ overlay, which contains 5% copper, achieves 10,200 psi and is hardened by a proprietary process that modifies the overlay's molecular structure to form a black, fatigue-resistant shield rated 24% stronger than standard tri-metal overlays. Combined with King's RadiaLock™ crush height optimization, EccentriX™ eccentricity profiling, and narrowed crank-cheek design, the CR4507XP is built to handle forged crankshaft geometry and the demands of circle track, drag, and high-output street engine builds on the Mazda MZR/Ford Duratec platform.

CR4507XP is sold in Standard (STD) sizing, making it appropriate for engines where connecting rod journals remain at factory-original diameter. Prior to ordering, all rod journals should be measured with a calibrated micrometer to confirm standard sizing is correct. If journals show wear, scoring, or have been previously machined, undersized variants (such as CR4507XP.026) must be selected to restore proper oil clearance. King's Bull's Eye Tolerance™ - ±0.0001 in wall thickness variation shell-to-shell - ensures consistent oil clearance across all four cylinders with minimal selective fitting required during assembly, saving time on the engine build while delivering a high-precision result.