ACL Race Series Main Bearing Set Extra Clearance suit Chev LT1 5M7292HX

ACL has a proud & rich history in Motorsport – it is in their DNA. There is no better proving ground than the racetrack whatever it’s configuration. In the heat of competition proven technology always comes through.

The ACL RACE Series performance engine bearing range of today has a strong pedigree in motorsport & traces its roots back to the 1960’s with the manufacture of engine bearings for use in the world conquering Brabham Formula 1. Further experience in the Australian Supercars Championship & numerous other race codes has culminated in the current ACL RACE Series technology platform. The unique combination of design, metallurgy, engineering & precision quality control come together to deliver what engine builders expect from performance engine bearings

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Precision Manufacturing

ACL Race Series performance engine bearings are manufactured to exacting tolerances. Micron tolerance machining supported by precision measurement systems delivers consistent accuracy to key characteristics like wall thickness and crush. This ensures reliable fit and helps maintain consistent clearances.

Bearing Material Enhancements

A blend of characteristics to provide high strength and crankshafts. excellent seizure resistance.

No flash plating is applied to further improve bearing retention and maximise heat transfer.

Bearing Design Enhancements

• Crush increased for:

  • Improved bearing retention from higher radial contact pressure. Locks the bearing into the housing.

  • More effective heat dissipation through improved thermal transfer.

• Bearing Eccentricity

  • Definition: Gradual reduction in wall thickness between the crown and parting line.

  • ACL Race Series performance engine bearings feature increased eccentricity to increase improve shape adaptation to compensate for bore distortion at high speed operation.

  • Assists in the formation of hydrodynamic oil film.

• Main Bearings with Extended Grooves

  • Full (180°) grooved uppers with matching partial groove in lowers.
  • Reduces interruption to big end oil supply.

  • Tapered groove run-out.

  • Smooths big end supply cut-off avoiding pressure pulsing and cavitation.

A1

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ACL Engine Bearings

From a standard engine rebuild to a turbocharged street car or competition engine, choosing the correct bearings starts with the application, crankshaft dimensions and required oil clearance. The ACL range includes connecting-rod (big end) bearings, crankshaft main bearings, camshaft bearings and thrust washers for popular Australian, Japanese, American and European engines.

ACL Duraglide & Performance Duraglide

ACL Duraglide bearings provide options for engine repairs and rebuilds, with standard and undersize versions available across selected applications. Performance Duraglide bearings are identified by a P suffix in the part number. Availability and sizing vary by engine, so check the individual listing for the correct bearing set.

ACL Race Series Bearings

ACL Race Series bearings are designed for performance engines operating under increased loads and demanding conditions. Identified by an H suffix, the range uses a tri-metal construction with design features such as increased crush, increased eccentricity and enlarged internal chamfers to support bearing retention, oil-film formation and clearance around crankshaft fillets. Features vary by application.

• H: ACL Race Series bearings, available in standard and selected undersize options.
• HX: Race Series bearings providing an additional 0.001" (0.025 mm) oil clearance compared with the corresponding H-STD set on a standard-size crankshaft journal.
• HC: Calico-coated Race Series bearings.

Understanding Bearing Sizes

For rod and main bearings, undersize refers to the crankshaft journal diameter. A 0.25 mm undersize bearing set suits journals machined 0.25 mm below standard diameter; its thicker shells compensate for the smaller journal. Older applications commonly use imperial sizes such as 0.010" and 0.020", while many Japanese applications use metric sizes such as 0.25 mm and 0.50 mm.

HX extra-clearance bearings are different from undersize bearings. HX bearings use thinner shells to increase oil clearance on standard-size journals. Camshaft bearing oversizes and thrust washer sizes follow different conventions, so refer to the individual product description rather than applying rod and main bearing sizing rules.

Choose the Correct Set for Your Engine

An engine code alone may not identify the correct bearing set. Production changes, journal diameters, thrust-bearing positions and crankshaft modifications can affect fitment. Confirm the engine configuration and required bearing size with your engine builder or machine shop, and measure the assembled oil clearance during installation.