ACL Race Series Rod Bearing Set, tight clearance — eight tri-metal big-end shells for the 2.0 litre Theta II turbo bottom end, machined with a thicker wall so the assembled engine runs 0.025 mm (0.001 in) less oil clearance than our standard set.
Read this before you order: this is a clearance grade, not an undersize bearing. ACL list it on the same table as the standard and extra-clearance sets, all three for a crankshaft at standard journal size. It is the tight mirror image of the extra-clearance set. If your crankshaft has been reground undersize, this is the wrong part.
Who it is for. Two kinds of engine. One is a build where you want a tighter oil film than standard for better control and stability. The other is a crankshaft that measures a whisker under standard from ordinary wear or a light polish, where the thicker shell brings clearance back into specification without a regrind.
Fitment — ACL's own application guide names the i30 N. Hyundai i30 N 2018 on, Veloster N 2019-2022, Elantra N 2022-2026 and Kona N 2022-2023 — 2.0L Theta II turbo (G4KH). Journal and housing dimensions are unchanged from the standard set; only the wall thickness differs.
From ACL: tri-metal construction, with a lead-tin-copper overlay over a nickel barrier layer and a copper-lead-tin lining on SAE1010 high-tensile steel. The higher steel tensile strength improves bearing retention, and the increased eccentricity compensates for bore distortion and helps the hydrodynamic oil film form.
Details: 8 shells, one pair per rod; standard journal size with 0.025 mm (0.001 in) reduced clearance; rod housing bore 51.000-51.018 mm; crank rod journal 47.954-47.972 mm; wall approximately 0.0125 mm thicker per shell than the standard set.
Mixing grades is normal practice. ACL expect builders to mix adjacent grades on one journal to land on a target clearance — one tight shell paired with one standard shell halves the change, to 0.0125 mm (0.0005 in). The thicker shell goes in the most heavily loaded position, which on a connecting rod is the upper half.
Rod bearings only. There are no main bearings in this set.
A note on appearance. Race Series shells arrive with a dark tarnished colouring that can look black, brown or blue. ACL applies no cosmetic tin flash. It is deliberate, and it is not a defect.
Final oil clearance is the engine builder's responsibility. Measure the assembled bearing bores before you commit, and never polish the bearing surface to change it.
Availability: ON ORDER at our distributor as of 6 November 2026.
Not sure this suits your car? Ask us before ordering — we would rather check the fitment than process a return.