Is it a zero clearance engine

It is an interference engine. As far as the timing chain, they last longer than a belt. However, refer to the owner's manual to see if and when the manufacturer recommends replacing it. NOTE: If it is a chain, the manufacturer may not have a mileage interval for replacement. At that point, it is a matter of either doing preventative maintenance and replacing it, or waiting until you hear noise from it from being stretched.