To install these inserts, new threads are cut in the head with the provided tap, red hi temp silicone is applied to the threads on the insert before screwing it in, then the serrated part of the insert is expanded by using the large punch which is included in the kit. The punch has a taper on it which does the expanding. I find one or two good blows with a two pound hammer does the job. After the insert has been set, clean up any excess silicone and allow it to set up before installing the spark plugs or running the motor and you are done.
For the record, I’ve never had one of these inserts back out when removing the plug but I have had the wire inserts come out with the plug. That can be a pain as now the wire insert is tight on the plug and can be a bear to remove.
