Are you talking about a  Four Stroke motor   or  are  you asking  about the  OS  SF-46

Randy

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       This engine was in "storage" for many years and appears to be fouled with well aged castor oil.  The ring appears to be stuck to the groove.  I have been told that I can get an ABC p&c from Mecoa that will be a drop in replacement for this engine.  Do you know if this is true?

       I am not aware of anything like that and in any case, I wouldn't just start taking it apart and dropping in parts from the "erzatz" bin. If it's just gummed up, run it on appropriate fuel for a while and see if it runs OK, if so, just move on.

     And don't take this as a criticism, but you appear to have dozens of old engines in various states of repair, most of which were probably working in some sense when they were retired. Just find one that works, and they go fly it, and fix it only if it shows some problem in-flight. A 46SF isn't that old, and while I am sure you could get a new ring for it somewhere and replace it, but there's no reason to think there's anything wrong with it now and no particularly good reason to take it apart. I wouldn't assume something is broken/defective/in need of modification without at least trying it first.

    If just want to mess with engines, by all means go ahead, far be it for anyone to interfere. If you just want a trouble-free engine to learn stunt with, you probably already have many examples. If you want to take the shortest route to success, sell some of the old engines and get one new one that works and is supported, and leave it alone.

     Brett

        Hello Brett and Randy:

       Thanks for the prompt and informative replies.

        You have probably guessed by now that I am an engine junkie.  I have never met an engine that I did not like.  I do have an attic with some old engines and kits stashed away.  I do not like to keep an engine that is not capable of running very well thus my many questions regarding these old engines.

       One thing that is very evident is the fact that the new technology is far superior to the engines that I have stashed away in the attic. However, how much improvement in horsepower do I need to fly stunt and sport?  Perhaps an older OS, Fox, Enya, Fox ST stunt engine will provide me with as much entertainment as a modern engine.  I have seen the newer and vey expensive engines provide the same runs and ease of starting as some of the older engines. One situation that comes to my mind is a new PA engine compared to the older engines,  I know of a couple of great Fox .35 Stunt engines that give what I consider as good as it gets performance.  Of course it may be a bit more satisfying to possess the latest and very expensive power for ones stunt plane.  I was speaking to a chap who uses the Tester-McCoy Series 21 engines in his planes and does quite well with them.   I have on of these in .35 nib that I have never run due to the fact that I was convinced that they were too inferior to be mounted in a plane.

      In closing, there are a few criterion that I do insist from an engine.  These are ease of starting, a steady and consistent run are at the top of my list.  Some of my favourite engines consist of OS .35S, OS .40S,  Fox .40 Stunt, circa 1970 big case ST .35,  and HP .40.  Yes, I do have some great Fox .35 Stunt  and McCoy .35 RH engines but they do not get used very often as I seem to spend more time with the other engines despite the fact that they are ready to fly.  I must take my Goldberg Shoestring that is powered by a McCoy RH as it has never been flown.  "You can't take it with you." Lol

       Enough for now.

                                                                                                   Be well,

                                                                                                   Frank McCune

If you want to mess with engines and you only understand horsepower, fly speed.

   Oh, good Lord, I hope you are not getting this from anything I said.

     People can do exactly as they damn well please and follow or ignore anyone's advice, and they are still welcome to post/discuss/fly stunt. No one gets kicked out of stunt because they don't really want to try to compete in big contests. The vast majority of people will never make the NATs Top 20, and many will never get a competitive flight in Expert. And that is not a failing of them or the event.

     The beauty of stunt, and the reason is has been so successful compared to many/virtually all other modeling events, is that *winning contests is not all there is to it*. People fly stunt for a lot of reasons aside from just beating Paul/David/Ted. There are endless challenges that you can continually work towards with success that no one can ever master no matter how long they do it.

    Engine guys are just one aspect of that. There are a bunch of guys like Frank, what harm is there?  While stunt "engines" do not follow the usual model of engine guys (and it's remarkable how how much "common knowledge" about engines and power is insanely, absurdly, wrong leading to the usual absurd advice and engine abuse), the topic of how to get stunt engines to work to aid your performance is VAST and tends to dominate the discussion. 

    Until this thread, I had no idea what Frank's perspective was, now we do. Maybe that changes the way I would respond in the future, but he doesn't have to "go fly speed".

     If you don't want to talk to him, then fine, - but he doesn't need to "go fly speed".
 
     Brett