I would like to add one final comment to this thread. We are able to know when something such as what Kevin is experiencing without any engine disassembly.

Most if not all of us have oil pan drain plugs with a very strong magnet. We also have oil filters that can be examined. At every oil change carfully inspect the oil pan drain plug. It should be totally free of the little whiskers or pieces of steel that will start to show up if the cam or rollers have this problem.

A second check is to cut the oil filter apart and open the paper element. Since metal pieces are not as obvious as they would be on the oil pan plug, if none are detected visually, run a strong magnet across the element surface. Any steel pieces will literally jump to the magnet.

Inspecting an oil filter is always done when changing the oil on a plane and there is no reason why that practice cannot be done on our buses.

As a comment I change my oil every 5000 miles on average. It may be considered excessive, but if I were to follow the 20,000 mile recommended intervals a lot of internal engine damage could occur before I noted metal in the filter or on the plug. Unlike commercial operators who put 80,000 to 100,000 miles annually on their engines we only run ours sporadically so I chose my oil change interval because I consider our use to be severe duty.