I have been turning wrenches for over 30 years in the northeast so I am used to working with a torch and rusted and stripped bolts. I have used both over the years as helicoils have been around longer, but my personal preference would be to use the time-serts. They take one more step to install them as they need to be countersunk but I have never had one fail once you locktite them in there in for good were as I have had helicoils come out with the bolt after a while. I have never used them on a animal engine but I have used them on the exhaust in aluminum automotive cylinder heads with great results. If anyone remembers the Cadillac Northstar ring recall you know what I mean, they had such a problem that they actually came out with special tools and a repair procedure when the head bolts let go in the block. Got to love aluminum!