Your photo seems to show an alloy small idler.I suggest that you replace it with a steel one.The alloy ones wear rapidly and leave flecks of swarf in the teeth of the ATD pinion.We are working on a C Series Touring Comet and when turning the engine over using the kickstart lever, there is a very disconcerting metal-on-metal noise coming from the engine. See video here:
Does anyone recognize the sound or have any suggestion for what to try?
Thanks in advance!