Today the water pump on my 8N broke. The front of the casting along with the impeller broke. After I removed the pump I found that some of the pieces of the impeller fell into the engine block. Will this create any problems or will they sit in the bottom of the block. Here's a picture of the remaining impeller.
As Racer_X said, there "should be" no problems. If you can flush it out would be better. The piece(s) will be in the cooling system and the only moving parts in that system are the water pump and the thermostat. When you get her back together, watch the temperature. If the chunks are big enough they could plug the cooling system or they could move to stick in the thermostat or water pump causing problems. Good luck.