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Reduced price! Coussinets de bielles trimétal ACL et King Ford Cosworth YB View larger
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ACL and King trimetal connecting rod bearings Ford Cosworth YB

New product

Set of 8 trimetal connecting rod half-bearings for Ford Cosworth YB 2.0 16V.

  • Brands and treatment: ACL Race, King XP
  • Compatibility: Sierra RS Cosworth, Escort RS Cosworth
  • Engine codes: YBB, YBD, N5B, N5C, N5D, N5F
  • Available sizes: standard to +0.50 mm, increased-clearance version (HX / STDX)

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71,98 € tax incl.

-5%

75,77 € tax incl.

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  • The Ford Cosworth YB four-cylinder engine

    The Cosworth YB (2.0 litres) is a Ford 16-valve twin overhead camshaft four-cylinder engine, turbocharged, fitted to the Sierra RS Cosworth and the Escort RS Cosworth. ACL and King list the same bearing set for this engine: a single set covers the family.

    From the factory, these engines are fitted with standard production connecting rod bearings, sized for the loads of the original engine: as soon as power, engine speed or boost pressure increase, they reach their limits.

    Trimetal connecting rod bearings

    A trimetal bearing stacks three layers: a steel back, a copper-lead intermediate layer with high load capacity and an anti-friction running surface that protects the journal. The complete set contains 8 half shells, four pairs for a four-cylinder engine.

    The original bearing relies on an aluminium alloy over a steel back, intended for low to medium loads, whereas trimetal is designed for high, sustained loads: an aluminium bi-metal takes around 8,000 psi, a performance trimetal up to 12,000 psi, 50% more. Hence better resistance and better durability on turbocharged, supercharged and high-revving engines.

    Technical specifications

    Fitment dimensions common to all references
    ACL / King bearings
    Crankpin Ø 51.990 / 52.000 mm (King : 51.989 / 51.999 mm)
    Housing bore Ø 55.000 / 55.020 mm (King : 54.999 / 55.019 mm)
    Width 20.12 mm (King: 20 mm)
    ReferenceBrand and treatmentSizeWall thickness (mm)
    4B2166H-STDACL Race - UntreatedStandard1.496
    4B2166HX-STDACL Race - UntreatedStd, increased clearance (HX)1.483
    4B2166H-.25ACL Race - Untreated+0.251.621
    4B2166H-.50ACL Race - Untreated+0.501.746
    CR4440XPKing Racing - UntreatedStandard1.491
    CR4440XP STDXKing Racing - UntreatedStd, increased clearance (STDX)1.478
    CR4440XP0.25King Racing - Untreated+0.251.618
    CR4440XP0.5King Racing - Untreated+0.501.745

    Running clearance

    The running clearance is the gap between the bearing and the journal where the oil film flows.

    In operation, the crankshaft journal does not rub against the bearing: it rides on this oil film, which carries the load. Clearance sets the thickness of this film: too tight, oil flows poorly, temperature rises and the risk of seizure increases; too loose, oil escapes, the film loses load-carrying capacity and oil pressure drops. The right clearance is the balance between adequate lubrication and a well-maintained oil film.

    Size / gradeWhen to choose itACL Race SeriesKing XP
    Standard (STD)Standard journal, not reground0.055 to 0.065 mm
    Increased clearance (HX / STDX)Wider clearance: high oil flow, high rpm0.080 to 0.090 mm
    +0.25 mmJournal reground to 0.25 mm0.055 to 0.065 mm
    +0.50 mmJournal reground to 0.50 mm0.055 to 0.065 mm

    Checking on assembly: lay a calibrated strip (Plastigauge) on the journal, torque the rod cap to spec, then compare the crushed strip against the gauge to read the clearance.

    Plastigauge

    Order the Plastigauge →

    Technical guide

    The ACL and King rod bearings shown here are trimetal bearings, designed for engine building and racing. Compared with an original bearing, they handle far higher loads: they cope with increased power, high rpm or the addition of a turbo or supercharger, where a standard bearing quickly reaches its limit.

    The two brands

    ACLACL Bearing Company, an Australian manufacturer of high-performance engine bearings since 1949, offers with its Race Series precise trimetal bearings, available in many sizes and proven on built engines worldwide.
    King RacingKing Engine Bearings, an Israeli manufacturer of high-performance engine bearings since the 1960s, offers with its pMax Black trimetal alloy bearings designed for heavy loads.

    Construction and advantages

    CriterionACL Race SeriesKing Racing
    Cross-sectionCross-section of an ACL Race Series trimetal bearingCross-section of a King Racing trimetal bearing
    TypeHigh-performance trimetal bearingHigh-performance trimetal bearing
    Country of manufactureAustraliaIsrael
    ConstructionTrimetal: steel back, copper layer, soft surfaceTrimetal: steel back, copper layer, soft surface
    AlloyRace Series (copper-lead)pMax Black (hardened copper-lead)
    Protective coatingNoNo
    Available sizesStandard to +0.50 mm (+ increased clearance HX)Standard to +0.50 mm (+ increased clearance STDX)

    Vehicle compatibility

    This connecting rod bearing set fits the Cosworth YB four-cylinder engine of the following Ford models:

    BrandModel (chassis)Engine codePowerYears
    FORDSIERRA I Hatchback 2.0 4x4N5B, YBB204 hp1985–1987
    FORDSIERRA II Hatchback 2.0 RS Cosworth / 2.0 RS500 Cosworth / 2.0 16V Cosworth / 2.0 16V Cosworth Cat 4x4N5B, N5C, N5D, YBB, YBD204–227 hp1987–1993
    FORDESCORT V (AAL, ABL) RS Cosworth 4x4N5F220 hp1991–1995
    FORDESCORT VI (GAL, AAL, ABL) RS Cosworth 4x4N5F220 hp1995–1998