hi I have a v5 1999 sti what happened was i boosted it in 3rd gear then it made a horrible noise its hard to explain then engine died I pulled over tried to start and it was like it was seized I got it home pulled cam belt cover off. belt is fine tried turning engine by hand will only move half a turn and sounds like something inside is jammed or hitting something I pulled starter motor out still same thing iv taken gearbox of flywheel and pressure plate still the same engine is completely stock any help would be appreciated as iv only had the car 3 weeks it has 175000 ks on it