In several posts here in that forum I found some more or less clear hints about the poor quality of timing gears in early olds.

I have a 1968 Toronado with more than 150'000 miles. And I have all the papers and I assume that timing gears and chain have never been replaced.

I runs - good.

Would you people recommend me to change timing gears as a precaution? To prevent a possible jump of timing causing damage to the engine?

 

My rule of thumb is 50,000 miles on a timing belt, 80,000 miles on a stock timing chain with plastic gears, and 150,000 miles on a roller chain with metal gears. If I were you, I'd plan on a new timing set soon.

 

X2

I had a plastic gear give out when i was racing a guy on the highway . It clogged my pickup and spun a bearing. Ill never put an engine in my car now without putting a steel gear in.

 

X3
here's a timing gear with 37k on it. Already a chunk missing and wore down to the aluminum between teeth. Not shown are all the little cracks that would be chunks in
short time.

 

Stock timing chains had plastic gears? What part was plastic, around the teeth? How can you tell if your timing gears are the original ones? I thought mine were original but there was no plastic on them that I could see...they looked to be all metal. There was no plastic in my oil pickup screen either luckily...

 

The timing gears were coated with plastic to make them silent. People driving Oldsmobiles in the 60s and 70s didn't want a loud car, they wanted top of the line luxury.

 

My blue Toronado, the timing gear was shot, and this car has only 88,411 miles. The wacko thing about it that, the motor NEVER JUMPED THE TIMING! ANd the chain had about a 1/2" slop to boot !
Here is the story about the Toronado.
http://www.cardomain.com/ride/3103713

 

Olds,Chevy,Buick and Pontiac all did this plastic covering of the timing gear.s
Replaced these units with steel.