Rebuilding a certified engine??

[Mike Switzer]

This is why once you install a certified engine on something not certified it can not go back on a certified airplane, not without a complete tear down and inspection.

Tony

Incorrect. As long as any maintenance is in compliance with FAA requirements for that engine, and all engine maintenance is logged in the engine logbook & signed off by an A&P it is still considered to be a legal, certified engine.