"Jay Honeck" wrote
In my case, the Warrior had a thorough pre-buy, by a reputable shop

No, we've already established that the shop was disreputable.

the compressions were great

Were they? Or was the prop wiggled until they looked good? Have you
ever done a compression check yourself? Did you watch them do the
compression check? Unless the answer to both questions is yes, how do
you know it was done properly?

but the jug nevertheless failed a few months
later, because the engine was actually missing a critical internal part.

Yes, we know. But what we don't know is if there was already a worked
spot on the jug that a proper compression check would have detected.
Maybe yes, maybe no. We're never going to know, either. Sometimes
jugs fail because an error was made in the assembly. Sometimes they
fail because of a manufacturing defect. Sometimes they fail because
of the way they are operated. Replacing jugs is a fact of life.

Buying an old plane is always a roll of the dice, but -- had I known then
what I know now -- I would have more thoroughly researched the *seller*, not
so much the aircraft.

Yes, if you don't know much about aircraft but know a lot about
people, that might be your best bet. But aircraft are a lot easier to
inspect - if you know how.

The seller was an FBO manager, from Marshfield, WI. I found out later that
he was apparently selling off his aircraft to pay his way out of bankruptcy.
Had I known that at the time, I would have walked away from the table, since
a guy going bankrupt is NOT going to be able to maintain an aircraft
properly.

He could afford nice paint and interior though...

That missing rotator cap -- left out because he probably had the
wrong length push-rod in stock -- could have killed me.

If a failed jug can kill you, maybe you need to rethink the way you
fly. Jugs fail, for all sorts of reasons, and with depressing
regularity. And BTW, pushrods are cheap and you can get them quickly.
More than likely, he left out the part by mistake.

Michael