Any time I've taken apart an automobile engine, there is the ever-present
ridge at the top of the cylinder at the limit of piston travel.  The
exception is the one and only waterboxer engine I've rebuilt- it had no
ridge at all despite 120k mi.  After cleaning and honing there wasn't even
a trace of a ridge, even though I had a ridge reaming tool ready to go.  Is
this the norm?  

Bill