" First and foremost, a plugged or misaimed lubricator, but also, excessive engine fibration (tuning, wear with age), shifty camshafts, wrongly tightened retaining nuts, etc. "

Very well said... I'd guess that inproper installation or bad parts causes the early demise of many timing gears. Heck, the new fiber gear in my 164 lasted about 1.5 seconds... it being seized due to a spacer that was too thick.

The fiber timing gear set in my 1800 have not been replaced since I got that car... and that was almost 300k miles ago. 300k very hard miles. And it too has been overheated to the point of completely seizing the engine. Twice.

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-Matt I ♥ my ♂