I know a lot of people think they need to break there engines in on a test stand or on the plane while not flying,

If you do this be care full and do not run for longer then a few min. at a time, You think that a lot of air is moving over the engine and cylinder but it is not, Most of the air is moving to the tips of the prop and not going over the engine, Plus most stands have a solid piece of wood behind the cylinder and air could not pass if it got there.

Even in the plane air is not moving over the cylinders and they will heat up if it is not flying.

I am rebuilding a engine now that was on a test stand and customer said he did not know what could have happened he just set it at about 3500 RPM and after 15 min. It just locked up, Well the cylinder and piston are cooked.

If you insist on breaking in with a stand or on the ground do it for short periods and let it cool between runs.

I will run maybe a tank through the engine while tuning and setting it up and then break it in where it will be running In the air


Milton