ACL Race Main Bearings (M20, M50, M52, M54, S50, S54)

Description Selecting Your Bearings We are asked time and time again about which bearing sizes are the right ones to purchase – if you are in any doubt, then choose the ‘Standard Sizing’ option for a bearing that ACL have formulated to be a replacement for the originals. ACL’s bearing clearances tend to measure at the larger side of OE tolerance, making them ideal for high performance applications. ‘0.025mm’ options have an oil clearance which is 0.025mm tighter than ACL’s standard option; this is for crankshafts that measure as being undersized by a very small amount; usually due to wear. ‘HX Extra Clearance’ bearings are the other way around, with 0.025mm more clearance than the standard size. These are generally only for extreme duty drag race applications and must be specified by an engine builder. ‘0.25mm’ and ‘0.50mm’. bearings, where available, are specifically for reground crankshafts. These options should be ignored unless your crankshaft has been machined to the correct specifications by your machine shop. In all cases it is advised that oil clearances are measured by an engine builder or qualified professional for the best results; bearing clearances are a critical element to engine longevity and performance and must not be overlooked.