Interesting discovery inside 318

I dont know but it was a new car may be tight enough clearance but it dident smoke and had no rings at all on the piston I seen it when he pulled it out of the engine. The car did not run rough until the plug would no longer fire then it came in with a misfire the second time when my brother tore the head and pan off to get the piston out. It had a little over 4 thousand miles on it