Just Miata JMCS01 - Crankshaft Saver (Crankshaft Extension) 1991-2005 only, not for 1990 short nosed crankshafts. Ignore 1 and 2 star reviews, buyers had short nosed crankshafts and didn't understand variation The Crankshaft Saver by Just Miata should be a part of every timing belt service performed on any first or second generation Mazda Miata. The Crankshaft Saver by Just Miata is 1) life insurance for your Miata's healthy crankshaft and 2) the ultimate crankshaft repair kit for damaged Mazda Miata crankshafts. Question: "What is wrong with all of the first and second generation Mazda Miata crankshafts. Answer: "The crankshaft snout is too short" The Crankshaft Saver fills in the problematic 14mm air gap at the end of the Miata's crankshaft. This air gap of over 1/2 inch in length is the source of many problems that ultimately result in catastrophic crankshaft failure. Crankshaft Saver will not only provide important life insurance for your healthy Miata crankshaft but Crankshaft Saver will repair any damaged Mazda Miata crankshaft keyway and crankshaft snout. CRANK SAVER DOES NOT ADDRESS THE 1990 SHORT NOSED CRANKSHAFT ISSUE. THERE HAVE BEEN TWO UNFAVORABLE REVIEWS DUE TO MIATA OWNERS NOT FAMILIAR WITH THIS CRANKSHAFT VARIATION. CRANK SAVER DOES NOT ADDRESS THE 1990 SHORT NOSES CRANKSHAFT ISSUE.