Longworth wrote:

We had a similar experience getting a factory overhauled Lycoming
engine through Air Power two years ago. For the core charge, we sent
them a certified check which they held uncashed and sent back to us
when they received the old engine back. The engine has been running
great for the last 350 hrs.

Does this "core charge" thing work similarly if one deals not with the
factory but with some "shop" that does the work? Or is Lycoming still
involved somehow?

- Andrew