Please see the post by stevebfl at the end of this thread: click

My interpretation of Steve's post is that the marks at the cam are not precision marks. So you cannot use them to judge chain wear.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References