i think that piece of metal is called a woodruf key or something...it's supposed to stop whatever is attached to the shaft from rotating independent of the shaft...
the notches on the pulley and the fan go over that key

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85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project