The "metal rubbing together" sound could be your starter motor failing to engage on the ring gear. If so, and you persist in trying to start it you will damage the ring gear, I dont know if the ring gear is seperable from the flywheel on fiats, but either way its a gear box out job.
Ive no idea what the starters are like to get off multi's but theres normally 2-3 bolts and a cable to disconnect. Simple in theory but often complicated by poor accesibility. just dont forget to disconnect the battery first.