Missing or damaged '90 - '93 Alternator tensioner Hardware? This is your solution! Genuine Mazda Miata replacement parts;
FE38-15-966 Tensioner Adjusting Bolt
FP02-18-363 Tensioner Block
99794-0840 Tensioner Block Holding Bolt
Fits all '90 - '93 Miata's OEM style alternator without a threaded hole in the lower ear. Note aftermarket alternators may use the 1.8 style WITH a threaded hole.