Broken Timing Chain Guide.
I have a 93 Altima 2.4 liter. It's almost about to roll on 200k. The timing chain guide broke in two seperate pieces. One of them was riding the camshaft and the other sounds like it's in the engine block. I have no idea how it would get there. The sound is hideous. The car still run and all the valves are moving. I suspect that it is riding around in the oil pan.
Is it possible that the other broken piece fell down the timing chain area and into the oil pan is getting struck by the crankshaft.
Merrell
sam17me@yahoo.com