I have installed many heli coils on engines without removing the head. You grease the drill and tap to catch most of the metal bits and turn the engine over without a plug before using it. Also, the shavings are almost always soft aluminum and won't hurt anything. The item shown does work, back in the day many V8 Chevys had a rear cylinder that would always foul plugs with oil and you just used one of those and they ran fine.