Posted for "Bruce Gray" <Bruce@glasair.org>:

 It all depends on the cylinder treatment.
 
 Chrome cylinders can require up to 50 hours to seat the rings.
 
 Nitrited cylinders (Lycoming new) require 8-10 hours.
 
 Cerminil cylinders seat in 1 hour or less.
 
 Bruce
 www.glasair.org