MJ McCarty

Hi all, I recently picked up a 93 runner around 188,00. On my way to work Friday my alternator belt broke. Got all 3 belts put them on, upon starting the belts started smoking. Found out my fan bracket was locked up. Went and got one of those and put it on. Started it up and did good for about 5 minutes then the motor started ticking. The tick would go up and down with rpms. I thought i might have dropped something in the timing cover so i took it all back apart and didn't see anything, Reassembled, started again and sounded good for about 10 minutes that time. It was about 20 degrees colder the last few days then it has been. So I'm just wondering what this tick might be, and if it is safe to drive. Any pointers would be great, thanks in advance!!