Posted for Rick Lafford <gliderguy89@earthlink.net>:

 This is just one data point but we routinely pull the power back on the Lyc
O-540 on our Pawnee towplane. Airport is 610 MSL. Full power to 2 - 3k feet
AGL and then a 110mph decent at 2300rpm to the runway. Typical cycle time is 6
- 10 minutes for a tow. We've never cracked a jug but we do replace them at
each overhaul. Last rebuild (Penn Yan Aero) went past 2,000 hours and
compression was fine. Since we do commercial rides a couple times a year, we
thought it prudent to do the rebuild.
 
 Rick
 
 Rick Lafford, (Legacy someday)
 Dansville, NY