(1) Noise – As intensity of detonation increases, the sound intensity increases & it is harmful.
(2) Mechanical damage – shock waves are so violent that it may cause mechanical damage like breaking of piston. It increases the rate of wear erosion of piston.
(3) Power output & efficiency decreases - Power output & thermal efficiency decreases due to abnormal combustion.
(4) Increase in heat transfer – Temperature of cylinder in detonating engine is higher than in non – detonating engine, hence increases the heat transfer.
(5) Carbon deposits- Detonation results in increased carbon deposits