Although I am in the minority, maybe a minority of one, I have to disagree with the "keep a good engine running" idea. Here are my reasons.
First, please read Gmas old message for some of the reasons why you might be concerned about an "old" engine. Here is the reference again:
http://www.337skymaster.com/messages...light=overhaul
Second, if you just keep running the engine, you have an increasing chance of having a catastrophic failure. If you do have such a failure, you cannot get credit for the core any longer, as core credit is only given for engines that were running when removed. So you run the engine longer, take the additional risk (see next paragraph), end up spending the same or *more* money in the end.
But third, most importantly to me, although we have twins, there is on every takeoff a period of time, albeit short, when an engine failure is a true emergency, and can result in an accident even with the best technique in a centerline thrust aircraft. An example is a short strips with obstacles, or even just a normal length strip with obstacles on a hot day. Another example is, since most twin pilots approach with power, an engine failure on final can result in an undershoot. And people do freeze up, or feather the wrong engine, or whatever. We all think that we will do better, but my position is that it is best to avoid the risk inthe first place as much as is reasonable. There is an old saying that a superior pilot is one who uses his superior judgement to avoid having to use his superior skills.
But the catch here is what each of us individually decides is a reasonable tradeoff between costs and avoidance of risk.
For me, if I have been running an engine from birth, and know how it has been maintained, and know that it has been run frequently through its life, I will run it to the TBO established for the same engine on a Seneca. If any of those ifs are missing, I will overhaul sooner. I would not risk my life, the lives of my passengers, or even just the airframe, just to avoid doing an overhaul a year or two sooner. In my life, I have experienced three actual engine failures, two in singles, one in a P337, and that is 3 more than I would ever like to experience again. (The P337 failure was on an 800 hour engine 200 hours after I bought the airplane, and I would have experienced that failure regardless of what we are discussing here.) If it costs me three or four thousand more to have it overhauled early, it is worth it to me, and I recommend the same policy to others who operate aircraft under Part 91.
If all that sounds holier than thou, I am sorry, but I am passionate on this subject. I don't want to loose any of you...
Kevin