my friends ver3 sti was idiling to cool the turbo etc down, when it suddenly made a crack sound and stopped,

upon removing the left hand side cam cover the plastic pulley had destroyed itself,

question is can i replace pulley, refit and align belt, and turn over engine by hand to see if it has bent any valves?

 

yes turnover by hand first and if that goes okay then do a compression check, if thats ok then start it.

 

if it has slipped then engine out bent valves. game over