Thread repair insert M14 for thread spark plug / cylinder head

Thread insert - also known as threaded bush - for repairing defective spark plug threads M14x12.7mm on the cylinder head. The defective original thread is extended to M18. To do this, the old thread is drilled out to 16.5mm with a drill and a new thread M18x1.5mm is cut. The thread insert must then, if necessary, be shortened in length so that the same coverage is achieved in the cylinder head as with the original spark plug thread! Otherwise the piston will be destroyed!