Originally posted by Bob Blaylock:
I would expect them to be keyed to the shafts, so that no adjustment would be possible. For them not to be keyed would, I think, introduce an unacceptable risk of slipping out of adjustment during normal use.
They are not keyed, they are bolted on flat. The process of adjusting them is awkward but routine for e.g. the dealership mechanics. (Loosening the bolt can be an awkward business... perhaps best done with an impact wrench.) The risk of slippage is not great because the forces exerted on it when the engine runs are very moderate.
