Yes. I have heard the same thing. My cousin said you could balance a quarter on the air intake it ran so smooth.tgreese wrote: ↑Tue Nov 14, 2023 7:34 am
Might be worthwhile to survey the AMC forum posts regarding these engines. I understood these engines were considered smooth, reliable and durable in their day; no obvious weaknesses. If the oil pressure and compression were good, I'd close it up and attribute your issues to abuse by the previous owners.
I am sure that's a bit of a stretch lol.
However, I would say that this plastic timing gear is an obvious weakness. The only thing I can think to explain this is AMC engineers were eager to experiment with new synthetic materials that were lighter, cheaper and easier to manufacture than traditional steel parts. Perhaps they just didn't foresee the lack of reliability.
That being said, the first synthetic material, Bakelite, was invented in 1907. Nylon came around a few years later in 1935. They had at least 30 years of experience with synthetic materials and should have seen the potential pitfalls of this design, as it could be a potentially catastrophic and easily avoidable failure.