Enginetech BB121J25 Connecting Rod Bearing Set Ford Mazda 2.3L DOHC 0.010in Undersize

The Enginetech BB121J25 is a connecting rod bearing set sized 0.010 in. (0.25mm) undersize, designed for the Ford and Mazda 2.3L DOHC 16-valve Duratec/MZR four-cylinder engine. This set is engineered for engine rebuilders who are working with crankshafts that have been ground to the first undersize, ensuring proper oil clearances are restored after a grind.

Key Specifications:

• Undersize: 0.010 in. (0.25mm)
• Crankpin Journal Diameter: 1.9677–1.9685 in.
• Housing Bore: 2.0875–2.0883 in.
• Oil Clearance: 0.0010–0.0020 in.
• Shell Filter Part Number: C4507
• Number of Bearings in Set: 4
• Cross-Reference: CB-1838AL, 4930A, 4B1870A, CER4507SI

Key Features:

• Manufactured from advanced aluminum-silicon alloy for superior fatigue strength, conformability, and embeddability
• Precision machined on state-of-the-art equipment for consistent bearing wall thickness and accurate oil clearances
• Parting line chamfers precisely controlled to allow proper oil bleed-through without sacrificing oil pressure
• High-strength material delivers excellent load capacity along with strong anti-friction properties including wear resistance and anti-seizure characteristics
• Direct replacement fitment — no modification required

Enginetech has been the choice of professional engine rebuilders for over 25 years. The BB121J25 rod bearings deliver the precise tolerances needed for a reliable, long-lasting engine rebuild on the Ford/Mazda 2.3L Duratec and MZR platforms.