Appart from correct heat rating, what other precautions should be taken during installation of spark plugs?
Ensure the spark plug has the correct thread reach. The engine will not operate without the proper thread reach. If a spark plug with the wrong thread length is erroneously used, the piston or valve could strike it and damage the engine. Moreover, there is also the concern that the electrode could overheat and melt. Ensure the spark plug has the correct projection dimensions. There are several types of spark plug igniter shapes. Sometimes even when the length of the thread is correct, installing a spark plug with long metal shell projection dimensions may cause it to be struck by the piston or valve and result in engine trouble. Only use projection type plugs as specified by the manufacturer.