Hello, with my car is now the 3rd timing belt change, the interval is 120,000km. Newer engines, with similar performance, have however now partly double alternating intervals.. What exactly does the interval actually depend on, however, in essence? Direction/number of deflections of the belt, stress/conductor, thermal influences or almost exclusively material quality? If you read on the internet, you read that modern timing belts from clearly resistive There is the question, if this is the case, whether these materials are now taken for all timing belts, so also for those intended for older engines. That could mean then that one no longer has to change theoretically(!) bluntly all 120,000km. I change this with me, of course, nevertheless cautiously, but I was just interested in it now. Lg