Review on TimeSert Spark Plug #4212 Thread Repair Kit M12x1.25 by Stephen Parkell

I've used Helicoil quite a bit in the past. They are fairly easy to use, but lack performance in some applications. Time-Sert solves this problem by using a solid steel insert instead of a flimsy metal spool. They offer many sizes, but this spark plug kit is for spark plugs only. They're not cheap, but they don't replace the cylinder head. After using this very basic set I will never use coiled coils again.