Unusual engine failure - rings

[michel richard]

The 2.2 E all-stock engine that I had, has been taken apart, with only a few thousand miles on it. The reason is that I'm going to a high compression, twin plug short stroke 2.5. Engine ran fine when taken apart, but did have a tendency to smoke, sometimes quite a bit.

Anyway, it turns out that the second piston ring, and the second ring only, was broken on 5 cylinders ! First ring and oil scraper were fine on all cylinders.

I revved the enigne to 7.5K a few times, for very short period. On the other hand, I don't think I ever overheated it. It did run pretty rich at first, and it may have suffered from cylinder wall washdown. I did have a problem with ignition at one point, where timing would advance to something like 70 degrees around 4,000 rpm, obviously accompanied with massive power loss. It took some time to figure that one out (Bad MSD unit), but I would'nt stay at that rpm very long.

Has anybody ever seen something like that, any idea how that might have occured.

[Mr Beau]

Improper ring gap? Normally it's the first that takes the beating if detonation occurs.