All B-series engines are interference design.
Valves and pistons can collide (and often do) if the belt fails.
Based on what you're telling us, it sounds like the tensioner has failed and that's what has allowed the belt to go slack.
It's probably time to pull the head and see how bad the damage is.
__________________
:: :ToDspin: - supermod
- but who gives a shit?
:: HAN Integra FAQ: If, by some miracle, yours hasn't been stolen... check it out!