Was there a lip on one of the main bearings (thrust) bearing to stop the foreward and back movement of the crank? If not on the bearing, was there a seperate package with some half moon shaped pieces to be inserted before you put the main cap on. I have heard this noise when the thrust bearings are worn. Stops when you push in the clutch because crank is pushed foreward by pressure on clutch mechanisim. Just an ides, I could be off base.
Truck Tinker