ORIGINAL: Sport_Pilot
Glazed cylinders are caused by heat and small worn bits of metal plugging the valleys between high points. For the life of me, I don't know how an engine can get glazed with lots of raw fuel and oil pouring over the cylinder walls. Running excessively rich should only be done for a tank or so and helps to prevent the engine from overheating, washes out any worn metal, and helps to seal the rings which means more compression which in push's the rings out against the metal.
this is actually what glazing is
The primary deterrent of break in is this heat. Allowing to much heat to build up at the ring to cylinder wall interface will cause the lubricating oil that is present to break down and glaze the cylinder wall surface. This glaze will prevent any further seating of the piston rings. If glazing is allowed to happen break in will never occur. We must achieve a happy medium where we are pushing on the ring hard enough to wear it in but not hard enough to generate enough heat to cause glazing. If glazing should occur, the only remedy is to remove the effected cylinder, re-hone it and replace the piston rings and start the whole process over again.
the oil cooks onto the metal like a glazed coffee cup
so I think running sloppy rich ensures cool running it should break in fine
I think 2 gallons is excess but my experience has been that my engines run better after two to three gallons of run time but not all in break in mode just a tad to the rich side