Big nose crankshaft bolt, 1991-05

While this bolt isn't typically replaced with a timing belt change, if yours is especially old (i.e., it's been re-torqued many times thanks to many timing belt changes), it's not a bad idea to replace it. If you've used your existing bolt to pull on a press-fit crank pulley (like our ATI damper), it's a good idea to use a new bolt to hold it in place. Be sure to use blue Loctite and torque to 116-122 lb-ft.  Fits 1991-2005 Miatas. 1.6 engines could have a small nose crank (1990-1991, four slots in the face of the crank pulley) or a big nose (1991+, 1991-1993 have eight slots in the face of the crank pulley, 94-05 have no slots) - this bolt is for big nose engines only, it won't fit small nose engines.