I have a friend who is a technician at a shop I use to work at, who had a Focus with an internal problem such as you described. He had replaced the timing belt and driven the car around for 3 months then next thing he knows- broken connecting rod. He had to send the head to a machine shop to be repaired. The connecting rod did not damage the block so he replaced the connecting rod and the piston. He was told by the machine shop that this was "a common problem" which they have seen several times. I would inspect the internal parts of the engine before saying that the engine needs replaced. On the other hand, the cost to repair versus replacing may become a factor. This bit of information may pertain to your problem and then again may not. I hope it is useful! | 
