It is absolutely necessary to tighten a spark plug to the specified turning angle or torque setting. If the torque is set too low, there is a risk of compression loss. Additionally, the insulator and electrodes may also be damaged as a result of excessive vibrations. If the torque is set too high, however, the metal shell of the spark plug will be over-stressed, increasing the likelihood of it yielding or expanding. Expansion can cause the heat dissipation zones to be disrupted. Overheating, melting of the electrodes and even engine damage are other potential outcomes.