Genuine Mazda Connecting Rod Big End Bearing Set – STD / 0.25 / 0.50mm • LFY3-11-SE0A / LFY3-11-SF0A / LFY3-11-SFXA

Genuine Mazda Connecting Rod Big End Bearing Set – Standard / 0.25 mm / 0.50 mm

Genuine Mazda connecting-rod big-end bearing set for Mazda MX-5 Mk3, Mk3.5 and Mk3.75 NC models with 1.8 or 2.0 MZR engines, available in standard, 0.25 mm oversize and 0.50 mm oversize options.

The connecting-rod bearings fit between the connecting rods and the crankshaft journals. They provide the controlled oil-film bearing surface that allows the crankshaft to rotate while transferring combustion loads through the connecting rods.

Each selected variant contains four complete bearing pairs, comprising upper and lower shells for all four connecting rods. One selected set is therefore sufficient for one four-cylinder engine.

These are the later or uprated Genuine Mazda MZR connecting-rod bearing sets. They are offered in three sizes to suit either an original standard-size crankshaft or a crankshaft that has been professionally reground.

Important size-selection information: The 0.25 mm and 0.50 mm options are repair-size bearings designed for crankshaft journals that have been professionally machined to the corresponding undersize. They are not performance upgrades and must not be selected solely because the original bearings are worn.

The crankshaft journals must be measured accurately before ordering. The selected bearing set must correspond with the finished journal diameter, and the final oil clearance must be measured during engine assembly.

• Part type: Connecting-rod big-end bearing set
• Common names: Con-rod bearings / big-end bearings / connecting-rod metal set
• Mazda catalogue description: Metal Set, Connecting Rod
• Engine family: Mazda MZR LF / L8
• Available sizes: Standard, 0.25 mm oversize and 0.50 mm oversize
• Contents per selected variant: 4 bearing pairs / 8 individual shells
• Quantity required per four-cylinder engine: 1 complete set
• Quantity supplied: 1 complete set in the selected size
• Connecting rods included: No
• Crankshaft included: No
• Brand: Genuine Mazda

Available variants:

• Standard – LFY3-11-SE0A
• 0.25 mm Oversize – LFY3-11-SF0A
• 0.50 mm Oversize – LFY3-11-SFXA

Standard size – LFY3-11-SE0A: Intended for an engine whose connecting-rod crankshaft journals retain the standard finished diameter and remain within Mazda's specified limits for size, taper, ovality and surface condition.

0.25 mm oversize – LFY3-11-SF0A: Intended for a crankshaft whose connecting-rod journals have been professionally reground by 0.25 mm. Do not install on standard-diameter journals.

0.50 mm oversize – LFY3-11-SFXA: Intended for a crankshaft whose connecting-rod journals have been professionally reground by 0.50 mm. Do not install on standard-diameter or 0.25 mm-reground journals.

Possible reasons for replacement:

• Low engine-oil pressure caused by excessive bearing clearance
• Knocking from the lower engine under load
• Scored, worn or heat-damaged bearing shells
• Metal contamination following lubrication failure
• Crankshaft regrinding during an engine rebuild
• Preventive replacement during a full bottom-end overhaul

Fitment advice: Select the bearing size by precision measurement of the crankshaft journals and connecting-rod housing bores. Do not rely on the engine model, mileage or appearance of the removed bearings to determine the required size. Any crankshaft grinding should be completed by a competent automotive machine shop before the bearings are ordered.

Measurement requirements: Check each crankshaft journal for diameter, taper, ovality, scoring and surface finish. Measure the connecting-rod housing bores with the caps installed and tightened correctly. After fitting the selected bearings, verify the assembled oil clearance using calibrated measuring equipment or an appropriate bearing-clearance gauge.

Other items to consider: Inspect or replace the connecting-rod bolts where required, main bearing set, thrust bearings, oil pump, oil-pump pickup, sump gasket or sealant, crankshaft seals and engine oil filter. The crankshaft oilways and engine lubrication system must be cleaned thoroughly following any bearing failure.

Useful tools / consumables: Outside micrometer, bore gauge, calibrated torque wrench, bearing-clearance gauge, engine assembly lubricant, lint-free cloths, suitable solvent, ring compressor and clean engine oil.

Difficulty guide: DIY Difficulty: Expert / Engine Rebuild. Correct installation requires engine dismantling, precision measurement and strict cleanliness. Incorrect bearing-size selection or oil-clearance measurement can cause immediate loss of oil pressure, bearing seizure or serious engine damage.

Why Genuine Mazda? Genuine Mazda connecting-rod bearings are manufactured to the original shell profile, width, oil-clearance specification and repair-size increments required by the MZR engine. Correct bearing geometry and sizing are essential for maintaining the designed oil film and supporting the crankshaft under combustion load.

What’s in the box: One complete Genuine Mazda connecting-rod bearing set in the selected size, containing four upper and four lower bearing shells for all four connecting rods.

Installation notes: Work in a clean engine-assembly environment. Confirm the crankshaft and connecting rods are serviceable before installation. Keep each connecting rod and cap correctly paired and orientated. Clean the bearing seats without removing material, install the shells dry against the rod and cap, apply assembly lubricant only to the running surfaces and verify the bearing clearance before final assembly. Tighten the connecting-rod fasteners using the applicable Mazda sequence and specification, then confirm that the crankshaft rotates freely after each rod is installed.