HI Gary

If the ENYA still has good compression, and there are no bearing noises, I would suggest just keep running it. Engines don not necessarily go lean when they wear out. I have seen many people use wornout engines and still get good runs, The power will most alway be less after they wear .

Randy

Some engine will use more fuel at the end of their life... but not all ...many engines burn more fuel when they are new and burn less as they wear out. Some engines  leak fuel badly when they wear out..others do Not. it is hard to put down a perfect exact never changing set of rules  for telling if an engine is worn out or not.  Not all engines behave the same.
Then you also get into the part where an engine is still good in the cool months, but very marginal when it is hot...exact same engine no differance...diagnosing an engine over the phone line or internet is not exact and sometimes impossible to do.
However if it has very low or no compression it's a pretty safe bet its worn too much and time for a rebuild

Randy

Going on what Brett said about his VF engines living quite a few years.  Can I reason that a NIB VF46 can still be a great choice for the likes of a drednaught or due to the lack of replacement parts should be shelved(or traded off) for the likes of a larger PA type on a muffler?

Hi Gordon

Either, your choice, The good thing is if you build an airplane for the engine and you need a replacement, the PA 40 , 51, 61, 65  will drop in same lenght  same motor mount holes, The only difference is a small change in the  needle  location. so your not stuck if something happens.
The PA s  will run very well on either  muffler or  pipe, the VF does run better on s pipe.

Randy

Going on what Brett said about his VF engines living quite a few years.  Can I reason that a NIB VF46 can still be a great choice for the likes of a drednaught or due to the lack of replacement parts should be shelved(or traded off) for the likes of a larger PA type on a muffler?

      Of course, it's not really a matter of one replacing the other, if you are planning on running a muffler. A few people have tried the VF with a muffler with very mixed results.  I would suggest if you are not going to run it on a pipe, that you would be much better off with the more-appropriately-timed PAs.


 For a VF,  I certainly wouldn't be overly concerned about spares.  The one item that is limited-life is the rear bearing. That used to be a problem since they were an odd-ball size, but Boca had them manufactured and they are easily available. Otherwise, for anything but the very demanding users, I can pretty well guarantee that you will not wear it out in normal use. Paul Walker and I have both managed to wear out exactly one 40 each, over the period from 1988-1998. That's 10 years of hard high-level competition use. If it takes that to wear one out, then even heavy sport/stunt users or anything but the most die-hard competitors will not wear it out, ever. I guarantee that most people have fewer flights in their entire lives than either Paul or I got in those 10 years.
 
      But I switched to modern alternatives for the ability to support them as a competitor. Something goes wrong with a PA, I can call Randy that afternoon and have it fixed in short order. If you want mods, you can go so someone who actually knows what they are doing. That allowed me to run almost my entire NATs career with only one motor at a time - no backups. It's just not a concern that, say, the crank break or the ring goes over the hill between flights. The sort of thing that used to happen *all the time* with Foxes and ST's. The PA engines are, if anything, even more bulletproof than the VF, it's not going to wear out in normal usage.

   
     Brett