ACL 5M1644H-.25 Race Main Bearing Set +0.25mm Audi VW 1.8T 2.0 EA113 Golf A4 TT

Vehicle Fitment

• Audi A3 (8L) - 1.8L, 1.8T (1781cc, EA113 Gen 1)
• Audi A4 (B5/B6) - 1.8T, 2.0 (1781cc/1984cc, EA113 Gen 1)
• Audi A6 (C4/C5) - 1.8T, 2.0 (1781cc/1984cc, EA113 Gen 1)
• Audi TT (8N) - 1.8T (1781cc, EA113 Gen 1)
• Audi 80 (B3/B4), 90, 100 - 1.6L, 1.8L, 2.0L (EA113 Gen 1)
• VW Golf (Mk1/Mk2/Mk3/Mk4) - 1.6L, 1.8L, 1.8T, 2.0L (EA113 Gen 1)
• VW Jetta (Mk3/Mk4) - 1.6L, 1.8L, 1.8T, 2.0L (EA113 Gen 1)
• VW Passat (B3/B4/B5) - 1.6L, 1.8L, 1.8T, 2.0L (EA113 Gen 1)
• VW Polo, Caddy - 1.6L, 1.8L (EA113 Gen 1)
• Seat Ibiza, Cordoba, Leon - 1.6L, 1.8T, 2.0L (EA113 Gen 1)
• Skoda Octavia - 1.8T, 2.0L (EA113 Gen 1)

Fitment Notes

• EA113 Gen 1 only. This bearing set covers Audi/VW/Seat/Skoda 4-cylinder engines of the EA113 first-generation family (1983-approx. 2003/2008 depending on market), including 1595cc, 1781cc (naturally aspirated and turbocharged), and 1984cc (naturally aspirated and turbocharged) variants. It does not fit the EA888 TSI chain-driven engines introduced from 2008 onward.
• The .25 suffix designates this as the +0.25mm oversize bearing set - for use when the crankshaft main journals have been ground 0.25mm undersize. For standard journal diameter, use 5M1644H-STD. For crankshafts ground 0.025mm undersize, use 5M1644H-.025. For 0.50mm undersize, use 5M1644H-.50.
• Thrust washers (2T1644-STD) are sold separately and are not included in this set. Order them at the same time to ensure complete availability before grinding.
• Always measure crankshaft main journal diameter with a micrometer before selecting bearing size. Confirm actual clearance with Plastigage or a dial bore gauge after assembly.
• Sold as a complete set of 10 bearing shells (5 pairs, upper and lower) - sufficient for all 5 main journal positions in one 4-cylinder engine.

Features

• Tri-metal construction: copper-lead alloy lining bonded over a hardened steel backing, with a high-strength overlay plate - engineered for the sustained boost loads and high-RPM demands of built 1.8T and 2.0T EA113 engines.
• Hardened steel backing on all main bearings improves structural support of the bearing lining and maintains crush under the elevated crank loads associated with high-power 1.8T builds.
• High-strength overlay plate with reduced thickness provides improved fatigue resistance compared to OEM-spec bearings - a critical upgrade in modified or high-mileage VAG 4-cylinder builds.
• Increased bearing crush and tighter wall tolerances ensure consistent, secure seating in the block main journal bores, reducing the risk of bearing movement.
• Enlarged ID chamfers on bearing edges accommodate the larger fillet radii found on performance and aftermarket VAG crankshafts.
• 3/4-groove upper main bearings optimize oil supply to the main journals and to the connecting rod bearings through the crankshaft oiling passages.
• Elimination of flash plating on bearing backs improves heat transfer and maximizes grip between the bearing shell and the block main bore.
• Increased eccentricity compensates for bore distortion at high RPM and assists in the formation of a stable hydrodynamic oil film under load.

Specifications

• Part Number: 5M1644H-.25
• Product Line: ACL Race Series
• Application: Crankshaft Main Bearings
• Engine Compatibility: VAG EA113 Gen 1 - Audi/VW/Seat/Skoda 1595cc, 1781cc (incl. Turbo), 1984cc (incl. Turbo) 4-cylinder, 1983-approx. 2008
• Crankshaft Size: +0.25mm Oversize (for main journals ground 0.25mm undersize)
• Shaft (Main Journal) Diameter: 53.708-53.728mm (2.1144-2.1153 in)
• Tunnel (Housing Bore): 59.000-59.019mm (2.3228-2.3236 in)
• Maximum Wall Thickness at Crown: approx. 2.627mm (0.1034 in)
• Maximum Overall Length: 18.49mm (0.728 in)
• Bearing Material: Tri-Metal Copper-Lead Alloy / Hardened Steel Backing
• Thrust Washers: Not Included - order 2T1644-STD separately
• Quantity: Set of 10 Shells - 5 Upper + 5 Lower (complete engine set)

Included Components

• 10x Race Series Crankshaft Main Bearing Shells - +0.25mm Oversize (5 upper, 5 lower)

Product Description

The ACL Race Series 5M1644H-.25 crankshaft main bearing set is the +0.25mm oversize option for the VAG Group EA113 Gen 1 inline-4 engine family - covering Audi, Volkswagen, Seat, and Skoda 4-cylinder engines from 1.6L through 2.0L (naturally aspirated and turbocharged) across a wide range of models from 1983 through the early 2000s. This includes the iconic 1.8T found in the Audi A4, TT, and VW Golf GTI, as well as the 2.0 NA variants across the broader VAG lineup. This oversize set is selected when the crankshaft main journals have been ground 0.25mm undersize - a more significant regrind typically required when journals have suffered deeper wear or damage.

Built on ACL's Race Series tri-metal platform, these main bearings deliver superior fatigue resistance and oil film stability over OEM VAG shells - an essential foundation for any serious EA113-based build. Note that these do not fit the later EA888 TSI chain-drive engines. Thrust washers (2T1644-STD) must be ordered separately. Always confirm clearances at assembly. Sold as a complete set of 10 shells for one engine.