Does anybody know if it's inevitable that a fibre timing gear on a 186 red motor will disintegrate during the life of the motor? Have they been known to not go at all?

Some say that no matter what, in its running life, without any word of warning, it will break down.

My belief is that when a motor has had little or unregular use, the fibre gear dries out somewhat as opposed to an engine that is maintained and used regularly.

I don't think usage pattern has any effect - in the 90s my daily driven ones went just as early as the grandpa cars I've bought over the years. Come to think of it, I never had a Commodore 3.3L that didn't strip it (unless I got to it first with an alloy replacement).

I had one chew out on a 202 HZ a while ago, and I mean chewed. About 3 or 4 teeth were gone. Drained the4 oil and a lot of fibre came out. Replaced the gear, got it going again, but the fibre must have gone through the oil galleries. Good oil pressure buy little oil flow. The result was not a pretty sight.

I have got approximately 200,000 miles from my original bore untouched 186 out of a HT. It has been my daily driver engine for over 15 years now. I have done heavy towing work with it too.