Engine turns then jams

engine, spin, sounds, stops, spins, hitting, freely, internally, causing, fine, turns, jams, parked, dropped, bearing, connecting, return, start, sounded, bearings

I have a 91 mr2 NA. Car ran fine then was parked. return to start the car and sounded like a connecting rod bearing. I dropped the pan all bearings ok. However when i spin the engine it spins and then stops. Sounds like something internally hitting and causing the engine not to spin freely. any possible cause as to such??