Randy,
You mentioned "heat cycling" during break-in.  Do you agree with the short runs and cool-off method of break-in, or do you recommend running full tanks? 

Thanks,
Kim Mortimore

HI Kim

This will vary some but using short runs of  2 to 6 ounces per run is best, use only a few ounces for the first several  runs, then use more fuel as the motor is coming in. For very stable motors like the PAs  you can use 4 to 6 ounces each run, be sure to follow the instructions for each type of engine, There are differant break in procedures  for  AAC and Lapped cast iron or  ringed setups.
The cool downs are very important, they let everything "normalize" and the metals get back to the sizes they all are when cool. this can be a problem with pinch fit ABC or AAC , If you try to rush things the piston is the last to cool down, this makes for a very tight fit some times, and engines that kick back and are hard to start.

Then on the other side I have had Steel-iron piston\sleeve set ups  where the piston would grow so much that the engine would lock up if not ran very rich after it got up to tempurature.
If you have any specific questions about one type of engine breakin I will be glad to address  that

Randy