what cause the spark plugs to blow out of motor then motor starts smoking

This is Kevin with NWA Auto Shop. Without seeing the vehicle, I can only theorize. Based on the limited information given, these are my thoughts. A) Improper torque when installing plugs. B) Excessive pressures based on intake leak allowing water into the cylinder. (Water doesn't compress) C) Mechanical issue in valve train not allowing exhaust valve to open sufficiently. (Excessive Pressure) Without seeing the car it is difficult to determine cause. Kevin