interesting, I was wondering what might happen here.
when I stripped out the threads for my oil sensor, my machinist told me that I was not going to be able to use a helicoil to fix it. He suggested using a kingsert or something similar with a solid construction.
were you told you can't use the helicoil because there's not enough metal, or because the oil fitting is a concern?
unfortunately, there wasn't enough metal to bore out for the size kingsert that I needed, so we just made our own adapter out of some bar aluminum stock...