Hi Scotty, great videos btw, I have a Nissan Sentra 160si Twin Cam 16v (GA16DNE).
At what millage do I have to think about changing the timing chain?

My exact car is the Nissan Sentra 2002 model made for Mexico

In the picture you can see on the right hand side of the air box is a tube that runs towards the left headlight behind the battery.

The mounting of the tube broke and I removed it because it caused rattling, engine sounds a bit deeper, will it cause a problem in the future?

Note: there is no electrical components connected to the tube whatsoever...Thanks

tube is just to slow noise, hurts nothing gone. Timing chains, i change em when they rattle or when timing jumps around when checked with a timing gun at idle