I suspect that you are correct that my fiber gear chipping is caused by the teeth touching the timing gear cover. The helical mesh between the crank gear and fiber gear would not allow any interference between them unless the timing gear was just manufactured incorrectly - not likely. The whirring sound could very well have been the fiber gear spinning against the timing cover. IIRC, the tooth damage was most pronounced near the small end of the timing gear.

What confuses me is why my gear stopped whirring and Tom's did not. Perhaps Tom has a little more end play in his cam than mine.

Thanks for helping,

Joe M