ALL pistons should be at least lightly honed before assembly. It is very typical for Sealed Power pistons to be too tight as manufactured. Just one more reason it pays to have someone build your SC engine who is familiar with the motors.When I tore the engine down, it had one spun bearing, and two others show a ton of wear. The same piston that spun the bearing galled the wrist pin to the point that I couldn't move it. The other pistons were in varying degrees of the same situation. I had to have the pistons honed out when having everything machined again.