wrote:
All these replies and not one serious answer.

They were serious, now you ask the proper question.



Let me rephrase the question.

On the Big Lycoming engines, at what compression reading would indicate a
need for an investigation. In other words, what compression reading is
considered a warning sign?

It depends. If the reading isn't in the mid 70's or above on a
particular cylinder then find out where the air is escaping and fix
accordingly. If the reading was zero you still wouldn't necessarily
overhaul the engine.