Hi, as Fly 7 says, I hope my reply gives you the answer you need. As far as I can see, you can pay to be instructed on an aircraft in which the engine is beyond the 12 year limit and is therefore being maintained on condition. But only if you are the sole owner of that aircraft (bizarrely).
However, in no circumstances can it be rented out to others for financial reward. Note, I'm referring here to the 12 year rule as applied to, for example, the Lycoming engine of an Enstrom or Hughes 269 (which is how I understood your original question) not that applied to the airframe of a Robinson....which is a whole different issue.