AOPA:

When oil burn rates get worse than two hours per quart in typical GA piston engines, it's time for a look-see. In fact, most mechanics would rather the investigation start when the engine burns more than a quart every three hours. Another variable in the tracking of oil burn is the type of coating your cylinders have. Those with no coating or "steel" cylinders will optimally burn about a quart in 10 hours. Cylinders coated with Engine Components Inc.'s (ECI) Cermicrome, on the other hand, may go as many as 25 hours or more without requiring a quart of oil. Cylinders with a channel-chrome coating generally burn the most oil with typical burn rates falling in the quart per four-to-eight-hour range. Of course, all engines are different and burn rates may vary. What's important to note, though, is whether the rate takes a noticeable swing away from its normal trends.

So sehe ich das auch. wenn das Triebwerk mit 0,3-05 qts/h 30 jahre lang problemlos läuft (bei voller Kompression) und der Ölverbrauch stabil ist – dann gibt es keinen Grund, den Motor zu zerlegen.