On 12/30/2012 11:11 AM, Wayne.B wrote:
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.

Well, I still suggest a 3/4" helicoil in an aluminum head, holds better
than a similar threaded 3/8", having a lot more thread area. So in the
case of a spark plug for instance, I do suggest that a spark plug in an
aluminum head will hold better in a helicoil... IN THEORY!


===

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


In a fix, our motor shop will drain the engine and inject a few
tablespoons of very heavy grease just inside the hole. Then they drill
upward and vacuum the grease and any chips away, followed by a solvent
flush and oil... They can do this with the engine still on the bike in
most cases for an oil plug which is the most common heli repair in our
industry. Anything structural, we would not use a helicoil at all.