I believe that large cylinder is the center runner, between the two roller bearings inside the vac pump, that actually rides on the lobed plate attached to the timing chain.

This must have been from a previous failure. I found black RTV on the Vac pump interface. I could not find a C clip on the timing chain. But I only went through it quickly once. As far as I could see there is only damage to the one link I attached above. Ill be replacing the chain.