Helicoils work fine if you want to restore original thread diameter. I have never used on on a taper thread though, I am not 100% sure they make one for it. Either way, it involves drilling and tapping so you are not saving anything unless you are going to continue using it for the oil feed in which case it will be under pressure and I would double check with the company that makes them that they won't leak. Of course they do have a website >>
www.helicoil.com