ACL 5M2327H-STD Race Main Bearings for GM Family II 1.6/1.8/2.0/2.2L Opel Holden

Vehicle Fitment

• 1982-2009 General Motors / Opel / Vauxhall / Holden / Daewoo - GM Family II Inline-4 Engines (1.6L, 1.8L, 2.0L, 2.4L)
• Daewoo - C20LE 2.0L Inline-4 SOHC 2v
• Daewoo - C20SED 2.0L Inline-4 DOHC 4v
• General Motors / Pontiac - 110ci (1.8L) Inline-4 SOHC 2v (naturally aspirated and turbocharged)
• General Motors / Pontiac - 122ci (2.0L) Inline-4 SOHC 2v (naturally aspirated and turbocharged)
• Holden - 1598cc 16JH Family II Gen1 Inline-4 SOHC 2v
• Holden - 1598cc 16LF Family II Gen1 Inline-4 SOHC 2v
• Holden - 1796cc 18JC Family II Gen2 Inline-4 SOHC 2v
• Holden - 1796cc 18JU Family II Gen1 Inline-4 SOHC 2v
• Holden - 1796cc 18LE Family II Gen2 Inline-4 SOHC 2v
• Holden - 1998cc 20JD Family II Gen2 Inline-4 SOHC 2v
• Holden - C18SEL 1.8L Inline-4 DOHC 4v
• Holden - C18XE 1.8L Inline-4 DOHC 4v
• Holden - C20LET 2.0L Inline-4 DOHC 4v Turbocharged
• Holden - C20NE 2.0L Inline-4 SOHC 2v
• Holden - C20SEL 2.0L Inline-4 DOHC 4v
• Holden - C20XE 2.0L Inline-4 DOHC 4v
• Holden - X18XE 1.8L Inline-4 DOHC 4v
• Holden - X20SE 2.0L Inline-4 SOHC 2v
• Holden - X20XEV 2.0L Inline-4 DOHC 4v
• Holden - Z18XE 1.8L Inline-4 DOHC 4v (Non-VVT)
• Holden - Z20LET 2.0L Inline-4 DOHC 4v Turbocharged
• Opel/Vauxhall - C20XE 2.0L Inline-4 DOHC 4v (16V)
• Opel/Vauxhall - C20LET 2.0L Inline-4 DOHC 4v Turbocharged
• Opel/Vauxhall - Z20LET 2.0L Inline-4 DOHC 4v Turbocharged
• Opel/Vauxhall - Z20LEH 2.0L Inline-4 DOHC 4v Turbocharged
• Opel/Vauxhall - Z20LER 2.0L Inline-4 DOHC 4v Turbocharged
• Opel/Vauxhall - Z20LEL 2.0L Inline-4 DOHC 4v Turbocharged
• Opel/Vauxhall - X20XEV 2.0L Inline-4 DOHC 4v
• Vauxhall - 1796cc Inline-4 SOHC 2v
• Opel/Holden - 16D, 16DA, 16JH, 16LF, 16N, 16SH Inline-4
• Opel/Holden - 17D, 17DR Inline-4
• Opel/Holden - 18E, 18JC, 18JU, 18LE, 18N/NV, 18S, 18SE/SEH, 18SV Inline-4
• Opel/Holden - 20JD, 20NE, 20NEJ, 20SE/SEH, 20SER, 20XE Inline-4
• Opel/Holden - C18NE, C18NT, C18NV, C18NZ, C18SEL, C18XE/XEL Inline-4

Fitment Notes

• This bearing set fits the GM Family II engine platform, which spans Opel, Vauxhall, Holden, Daewoo, and Pontiac applications sharing the same crankshaft journal dimensions.
• Standard size (STD) - intended for use with an unmachined, factory-specification crankshaft. If the crank has been turned, select the appropriate oversize (-.025mm, -.25mm, or -.50mm) instead.
• Covers both SOHC and DOHC variants of the Family II engine family.
• Includes both naturally aspirated and turbocharged engine codes where crankshaft journal dimensions are shared.

Features

• ACL Race Series tri-metal bearing construction - combines a steel back, copper-lead intermediate layer, and a high-strength overlay for superior load-carrying capacity.
• High-strength overlay plate with reduced thickness for improved fatigue resistance under sustained high-RPM loads.
• Hardened steel backs on all bearings improve support of the bearing lining and assist with retention in the housing bore.
• Increased crush design improves bearing retention and prevents micro-movement under high-power applications.
• Flash plating eliminated from bearing backs to improve heat transfer through the bearing and maximize grip between the bearing shell and housing.
• Increased eccentricity compensates for bore distortion at elevated RPM and assists in the formation of hydrodynamic oil films for better lubrication.
• 3/4-groove main bearing design optimizes load-carrying surface area while maintaining adequate oil flow to the connecting rod bearings.
• Enlarged inner diameter chamfers on bearing edges accommodate large fillet radii on performance and aftermarket crankshafts.
• Engineered to withstand higher RPM, elevated boost pressures, and increased cylinder pressures associated with performance-built and turbocharged Family II engines.

Specifications

• Size: Standard (STD)
• Bearing Type: Main (crankshaft)
• Construction: Tri-metal (steel back / copper-lead / high-strength overlay)
• Max Overall Length: 19.5mm (0.7677 in)
• Max Shaft Size: 57.995mm (2.2833 in)
• Min Shaft Size: 57.982mm (2.2828 in)
• Max Tunnel Size: 62.013mm (2.4415 in)
• Min Tunnel Size: 62.000mm (2.4409 in)
• Max Oil Clearance: 0.067mm (0.00264 in)
• Min Oil Clearance: 0.018mm
• Max Wall Thickness at Crown: 1.992mm (0.0784 in)
• Engine Family: GM Family II Inline-4
• Position: Main (crankshaft journal)
• UPC: 9315726451205

Included Components

• 1x ACL Race Series Standard Size Main Bearing Set (5M2327H-STD) - complete set of main bearing shells for all journal positions in the GM Family II Inline-4 engine

Product Description

The ACL Race Series 5M2327H-STD is a standard-size main bearing set engineered specifically for the GM Family II Inline-4 engine platform, covering a wide range of 1.6L, 1.8L, 2.0L, and 2.4L applications across Opel, Vauxhall, Holden, Daewoo, and Pontiac vehicles produced from 1982 onward. Whether you're rebuilding a naturally aspirated C20XE for track use, refreshing a turbocharged Z20LET for a high-boost street build, or restoring a Holden-powered performance vehicle, these bearings are designed to exceed OEM standards in both durability and precision.

ACL's tri-metal construction sets the Race Series apart from standard replacement bearings. Each shell features a steel back for rigid housing support, a copper-lead intermediate layer for superior load distribution, and a high-performance overlay plate engineered to survive the elevated cylinder pressures and sustained RPM demands common in modified Family II applications. The elimination of flash plating on bearing backs improves thermal transfer directly into the block, while increased eccentricity ensures proper hydrodynamic oil film formation even as the bore distorts under load. The 3/4-groove main bearing design balances oil retention on the load-carrying surface with adequate flow to the rod bearings.

Installation requires a factory-specification (unmachined) crankshaft. If the crank has been ground to correct surface damage or out-of-round conditions, select the matching oversize variant (-.025mm, -.25mm, or -.50mm) to maintain proper oil clearance. These bearings are compatible with both SOHC and DOHC configurations of the Family II family and with naturally aspirated and turbocharged engine codes that share the same crankshaft journal dimensions. For builders seeking a reliable, race-proven foundation for a high-performance Family II build, the ACL 5M2327H-STD is the benchmark choice.