{"product_id":"acl-trimetal-reinforced-main-bearings-bmw-316i-318i-z3-m40-m42-m43-m44","title":"ACL Race Series main bearings for BMW 316i, 318i, Z3 (M40, M42, M43, M44)","description":"\u003cp\u003eACL Race Series competition main bearing set (part number 5M1538H) for BMW 316i, 318i, Z3 (M40, M42, M43, M44). These support the crankshaft in the block and, in a tuned engine, are essential for ensuring oil properly reaches the entire crankshaft.\u003c\/p\u003e\u003cp\u003eThe structure is tri-metal, with a steel backing, copper-lead-tin lining, a nickel barrier, and a soft surface layer that conforms and prevents seizing even under very high loads.\u003c\/p\u003e\u003cp\u003eThe upper shells feature a full 180° oil groove, while the lower shells have a partial groove to ensure uninterrupted oil flow to the connecting rods, with a progressive groove end to prevent pressure spikes. Race Series bearings have higher crush and a slightly more eccentric shape than standard bearings, details designed to keep the bearing from shifting and ensure proper lubrication when the block and rods deform under load.\u003c\/p\u003e\u003cp\u003eIn standard size, ACL specifies this for a crankshaft journal diameter of 59.971 to 59.990 mm, and recommends an oil clearance of approximately 0.061 to 0.073 mm for this diameter. If the crankshaft is ground, the dimensions change.\u003c\/p\u003e\u003cp\u003eThey do not have the silver tin top layer of standard bearings, so their dark, brownish-black-bluish color is factory-standard and does not indicate a defect. ACL advises against polishing the bearing surface to adjust clearance; if more is needed, combine them with the HX version, which provides an additional 0.025 mm of clearance.\u003c\/p\u003e\u003cp\u003eIf the crankshaft has been ground or you are unsure of the required size, please contact us with your engine code before ordering.\u003c\/p\u003e","brand":"ACL","offers":[{"title":"Default Title","offer_id":50813077651790,"sku":"ACL-5M1538H\/11","price":169.69,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/7329\/0062\/files\/acl-main-bearings_cdbdc6f9-3bf2-4f82-9faf-7489b431bdfc.jpg?v=1735903619","url":"https:\/\/driftandgrip.com\/en\/products\/acl-trimetal-reinforced-main-bearings-bmw-316i-318i-z3-m40-m42-m43-m44","provider":"Drift \u0026 Grip","version":"1.0","type":"link"}