On Sun, 30 Dec 2012 10:44:22 -0500, "Eisboch" wrote:

True, but the material the heli-coil is installed in isn't any
stronger. A heli-coil is great for replacing stripped out threads
that need to be drilled out but it doesn't make anything any stronger.

===

I'm assuming you must have to pull the head to avoid getting drilling
chips inside the cylinder?