{"product_id":"acl-trimetal-reinforced-main-bearings-audi-1-6l-1-8l-2-0l-83-01","title":"ACL Race Series main bearings for Audi 1.6L, 1.8L, 2.0L (83-01)","description":"\u003cp\u003eACL Race Series main bearings for Audi 1.6L, 1.8L, 2.0L (83-01), part number 5M1644H. These support the crankshaft in the block, and in a tuned engine, they are responsible for ensuring that oil reaches the entire crankshaft properly.\u003c\/p\u003e\u003cp\u003eInternally, they feature three layers on a high-strength steel backing: a copper-lead-tin lining, a thin nickel barrier, and a lead, tin, and copper sliding layer, which is the surface that works against the crankshaft.\u003c\/p\u003e\u003cp\u003eThe upper bearings feature a full 180° oil groove, while the lower ones have a partial groove to ensure oil flow to the connecting rods is not interrupted, with a progressive groove end to prevent pressure spikes. Race Series bearings have increased crush and a slightly more eccentric shape than standard bearings, two details designed to ensure the bearing does not move and maintains proper lubrication when the block and connecting rods deform under load.\u003c\/p\u003e\u003cp\u003eIn standard size, ACL specifies them for a crankshaft journal of 53.958 to 53.978 mm and recommends an oil clearance of approximately 0.056 to 0.067 mm for that diameter. If the crankshaft has been ground, the measurement changes.\u003c\/p\u003e\u003cp\u003eThey lack the silver-tin flash plating of standard bearings, so their dark, brownish-black and bluish appearance is factory standard and does not indicate a defect. ACL advises against polishing the bearing surface to adjust clearance; if more is needed, they can be combined with the HX version, which provides an additional 0.025 mm of clearance.\u003c\/p\u003e\u003cp\u003eBefore ordering, confirm your crankshaft measurement (standard or ground); if you have any questions, write to us with your engine code.\u003c\/p\u003e","brand":"ACL","offers":[{"title":"Default Title","offer_id":50813077356878,"sku":"ACL-5M1644H\/8","price":75.42,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/7329\/0062\/files\/acl-main-bearings_7913c8e3-f06e-41e7-92a0-92b169710895.jpg?v=1735903611","url":"https:\/\/driftandgrip.com\/en\/products\/acl-trimetal-reinforced-main-bearings-audi-1-6l-1-8l-2-0l-83-01","provider":"Drift \u0026 Grip","version":"1.0","type":"link"}