I have a home made test stand made out of 3/4 plywood. Glued it together used a few times, modified it because of a four stroke engine. Used one one those universal engine mounts found in trainer kits, metal with clamp on bars to hold the engine in place. Later, I just used the airframe. Ran a Saito in the airframe using their recommend procedures and until I got it dialed in, them flew it. I am guessing I ran the Saito .91 for maybe 30 minutes, short runs. After I got the engine dialed in, I flew. No problems, still have the engine, still flying it. In the case to strokes, I bolt them into the airframe and go fly them. Most are ringless and need to get hot to really break in. I fly them, a little rich at first. After three or four flights, dial them in and fly them Never had a problem. So I kinda never use the test stand anymore. I had to dust it off to run one engine that was very tight. I heated the engine up with a heat gun, them fired it up. Ran it about 5 minutes. After that the engine was loose. So I flew it, no problems after that. BTW I always have some Castor oil in my fuels, maybe 2 to 4%, the rest synthetic oil. I attribute long life to the Castor used all the time, even in break ins.