Timing chain idler pulley

Hi bought a double cab sport model 2006 Tacoma 4.0l a year ago, Mexican made and seem to have all the problems that the typical truck have. After much repairs and replacement of parts the head gasket gave out and had to rebuild the engine, on the 50 miles oil change I pulled the small oil pan cover for inspection and found two broken rings that came from between the timing chain idler gear , motor runs good, how important are these and if not replaced what is the long term effect. Thanks for any advice, could not have done all I did without the helpful information that’s on this site reading here have become a favorite pass time.