Yes, the timing belt or timing chain is inside the engine casing and it can be bad when it or subordinate parts fail. Though a timing belt/chain failure causing

Yes, the timing belt or timing chain is inside the engine casing and it can be bad when it or subordinate parts fail. Though a timing belt/chain failure causing a catastrophic event for the engine itself, I don't think that's very common. What I'm referring to is called the serpentine belt and is often accompanied by what's called an accessory or AC belt.