It's most likely a rod bearing, main bearing, cam bearing. Something was starved for oil and has been damaged. Because I'm not there to hear it, I recommend you allow a mechanic listen to it. He / she will most likely be able to give you an idea of what bearing it is based on it's sound.
If you have any other questions, let me know.
Friday, October 17th, 2008 AT 8:54 PM