{"product_id":"acl-race-series-b-k-series-main-bearings","title":"ACL Race Series Main Bearing Set for Honda\/Acura B\/K-Series","description":"\u003cul\u003e\n\u003cli\u003eCompatible with B and K Series Engines \u003c\/li\u003e\n\u003cli\u003eFour Clearance Sizes Available \u003c\/li\u003e\n\u003cli\u003eRace Series Bearings Designed for Performance Applications \u003c\/li\u003e\n\u003cli\u003eComplete Main Bearing Set \u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- split --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli\u003e\u003ca class=\"active\" href=\"#Description\"\u003eDescription\u003c\/a\u003e\u003c\/li\u003e\n \u003cli\u003e\u003ca href=\"#VehicleFitment\"\u003eVehicle Fitment\u003c\/a\u003e\u003c\/li\u003e  \u003cli\u003e\u003ca href=\"#TechnicalData\"\u003eTechnical Data\u003c\/a\u003e\u003c\/li\u003e  \u003cli\u003e\u003ca href=\"#InstallGuide\"\u003eInstall Guide\u003c\/a\u003e\u003c\/li\u003e \u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\n\n\u003cli class=\"active\" id=\"Description\"\u003e\n\u003ch3\u003eACL Race Series Main Bearing Set - Honda\/Acura B-Series \u0026amp; K-Series\u003c\/h3\u003e\n\n\u003cp\u003eMain bearings are what stands between your crankshaft and a very bad day. On a built B or K-series spinning past 8,000 rpm, the loads going through those shells are nothing like what a stock engine sees, and stock bearings aren't built for it. ACL Race Series is what most serious Honda builders reach for, and this is the five-main set for B-series and K-series bottom ends.\u003c\/p\u003e\n\n\u003ch4\u003eWhich Part Number Do You Need?\u003c\/h4\u003e\n\n\u003cp\u003eThis is the whole decision, and getting it wrong means pulling the engine back apart. Here's what each suffix means:\u003c\/p\u003e\n\n\u003ctable\u003e\n    \u003cthead\u003e\n        \u003ctr\u003e\n            \u003cth scope=\"col\"\u003ePart Number\u003c\/th\u003e\n            \u003cth scope=\"col\"\u003eWhat It Is\u003c\/th\u003e\n        \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n        \u003ctr\u003e\n\u003ctd\u003e5M1959H-STD\u003c\/td\u003e\n\u003ctd\u003eStandard journal, baseline Race Series clearance\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003e5M1959HX-STD\u003c\/td\u003e\n\u003ctd\u003eStandard journal, .001\" extra clearance\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003e5M1959H-.025\u003c\/td\u003e\n\u003ctd\u003eFor a crank ground .025mm undersize\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003e5M1959H-.25\u003c\/td\u003e\n\u003ctd\u003eFor a crank ground .25mm undersize\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cp\u003eThe two STD sets are for a crankshaft with untouched journals. The undersize sets are for a crank that's been reground, and the bearing is thicker to restore proper clearance on the smaller journal. Order the size matching what your machine shop actually cut, and note that .025mm and .25mm are ten times apart, so read carefully.\u003c\/p\u003e\n\n\u003ch4\u003eH-STD Or HX-STD? Measure, Don't Guess\u003c\/h4\u003e\n\n\u003cp\u003eThe only difference is wall thickness. ACL machines the HX shell .0005\" thinner than the H, and since there are two shells around each journal, that works out to .001\" more oil clearance. Everything else about the two sets is identical.\u003c\/p\u003e\n\n\u003cp\u003eHere's what matters: neither one is an upgrade over the other. The bearing doesn't set your clearance by itself, your crank journal diameter and your housing bore do, and the bearing just fills what's left. So the right answer depends entirely on what your engine measures.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eStart with H-STD\u003c\/strong\u003e if your measured clearances already land where you want them. It's the baseline race sizing and it's what most performance street and motorsport builds run.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eGo HX-STD\u003c\/strong\u003e if you measure on the tight side and need room, or if the engine sees sustained heat and load where a thicker oil film helps. Track cars, drift cars, and anything living at high oil temperature are the usual candidates.\u003c\/p\u003e\n\n\u003cp\u003eWhat you should not do is order HX because it sounds like the better one. Too much clearance gives you low hot oil pressure and accelerated wear, and it'll look perfectly fine on the stand before it bites you. Mic your journals, measure your bores, and pick from there.\u003c\/p\u003e\n\n\u003ch4\u003eA Trick Most People Don't Know\u003c\/h4\u003e\n\n\u003cp\u003eYou're allowed to mix grades. ACL says it's common practice to combine adjacent grades like H-STD and HX-STD to dial in a clearance that neither one hits on its own. Two rules if you do it: no more than .0005\" difference between shells, and put the thicker shell in the most heavily loaded position. That's a legitimate tuning tool if you're a tenth of a thou off where you want to be.\u003c\/p\u003e\n\n\u003ch4\u003eWhy Race Series Instead Of Stock\u003c\/h4\u003e\n\n\u003cp\u003eThese are built for load, not for a 100,000-mile warranty. You get a high-strength overlay plate for fatigue resistance and a hardened steel backing supporting the lining, which is what keeps the bearing from failing under the cyclic loading a high-rpm engine generates. ACL also builds in increased crush for better holding power in the housing, and eliminates flash plating so heat transfers out of the bearing more effectively. On an engine making real power, all three of those matter.\u003c\/p\u003e\n\n\u003ch4\u003eYes, They're Supposed To Look Like That\u003c\/h4\u003e\n\n\u003cp\u003eWorth saying before you open the box. The final step in manufacturing Race Series bearings is electroplating, which leaves them a dark tarnished color that can come out black, brown, blue, or even copper. It varies between sets and sometimes within a set. That coloring is only on the surface atoms and has zero effect on performance. Your bearings aren't used, defective, or contaminated, they just look that way. Plenty of first-time buyers panic about this.\u003c\/p\u003e\n\u003ch4\u003eFitment\u003c\/h4\u003e\n\n\u003cp\u003eThis five-main set covers Honda and Acura B-series and K-series engines, including the B18, K20A2, K20A3, and K24A. Both families share the same main journal size, so one part number serves both, which is handy if you've got more than one Honda project on the stand.\u003c\/p\u003e\n\n\u003cp\u003eAs with any bearing purchase, confirm your crank size before ordering. If the crank has been reground, you need the matching undersize set, not the standard.\u003c\/p\u003e\n\n\u003ch4\u003eWho Should Run These\u003c\/h4\u003e\n\n\u003cp\u003eThis is for anyone assembling a B or K-series bottom end who's going past stock power or stock rpm. Fresh build, refresh, or a rebuild after a bearing failure, this is the set most Honda engine builders trust. Measure everything first, pick the size that gets you into your target clearance, and put it together right.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFits:\u003c\/strong\u003e Honda\/Acura B-series and K-series, five main bearings. \u003cstrong\u003ePart numbers:\u003c\/strong\u003e 5M1959H-STD (standard), 5M1959HX-STD (.001\" extra clearance), 5M1959H-.025 and 5M1959H-.25 (undersize for reground cranks). \u003cstrong\u003eConstruction:\u003c\/strong\u003e high-strength overlay plate, hardened steel backing, increased crush, no flash plating. \u003cstrong\u003eNote:\u003c\/strong\u003e verify measured clearances before selecting a size.\u003c\/p\u003e\n\u003c\/li\u003e\n\n \n\u003cli id=\"VehicleFitment\"\u003e\n \u003cul\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2013-2015 Acura ILX\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e1990-1993 Acura Integra\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e1994-2001 Acura Integra\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2007-2012 Acura RDX\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2002-2006 Acura RSX\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2002-2006 Acura RSX Type-S\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2004-2008 Acura TSX\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2009-2014 Acura TSX\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2003-2007 Honda Accord\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2008-2012 Honda Accord\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2013-2017 Honda Accord\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e1996-2000 Honda Civic\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e1999-2000 Honda Civic Si\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2001-2005 Honda Civic\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2002-2005 Honda Civic Si\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2006-2011 Honda Civic\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2006-2011 Honda Civic Si\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2012-2015 Honda Civic\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2012-2015 Honda Civic Si\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e1993-1997 Honda Civic del Sol\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2002-2006 Honda CR-V\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2007-2011 Honda CR-V\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2012-2016 Honda CR-V\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan class=\"tag\"\u003e2003-2011 Honda Element\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e \n\u003c\/li\u003e\n\n\n\n\n\u003cli id=\"TechnicalData\"\u003e\n\n\u003c\/li\u003e\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\u003cli id=\"InstallGuide\"\u003e\n\n\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n","brand":"ACL","offers":[{"title":"Standard","offer_id":46386533433378,"sku":"ACL-5M1959H-STD","price":111.1,"currency_code":"USD","in_stock":false},{"title":".025\"","offer_id":46386533466146,"sku":"ACL-5M1959H-025","price":111.1,"currency_code":"USD","in_stock":false},{"title":".25\"","offer_id":46386533498914,"sku":"ACL-5M1959H-25","price":111.1,"currency_code":"USD","in_stock":false},{"title":".001\"","offer_id":46386533531682,"sku":"ACL-5M1959HX-STD","price":111.1,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/2218\/5701\/files\/acl-race-series-main-bearing-s_oniy.png?v=1786482400","url":"https:\/\/www.hybrid-racing.com\/products\/acl-race-series-b-k-series-main-bearings","provider":"Hybrid Racing","version":"1.0","type":"link"}