I picked up a new RI at the factory with 4 hours total time. The factory changes the oil and filter just before delivery and checks if there is metal.
Then, the next oil change as per the factory, is at 29 hrs. total time, this is 25 hours more. Then at every 50 hours.
Well, as I was crossing the States to Florida prior to go through the Bahamas, Antilles, Trinidad Tobago, Brazil, Argentina and Chile, these 20 hours flying time to Florida were key to check everything.
So I decided to change the oil at 20 hrs. total time and then at the 30 hrs. total time just before leaving Florida.
I have an engine analyzer so I can have all CHTs and EGTs in real time. During the first 10 hours, the engine runs quite hot. The CHTs are all over 400?F at say 22" and full rich mix. The idea is to run the engine hard, at around 75% rated power so to have high cylinder/ring pressures that help mate the rings to the cylinder surface.
So even though the oil temp gauge read at about 180?F, it is clear that the oil in contact with the cylinder walls/heads is subject to a much higher temperature and degrades faster.
Therefore, careful cooldowns is a must to avoid "coking" the oil. Again the engine analyzer shows the cool down rate and I just waited as long as required till the rate was 0?F, this is the cylinders could not cool down anymore.
At about 20 hrs. total time, the CHTs started to go down and stabilized at about 30 hours as the rings seated and the friction reduced.
During this time the oil really has to withstand tough conditions and the engine makes some metal due to the normal cylinder/rings mating wear.
Then at 50 hrs. total time I switched to ashless dispersant oil plus antiwear additive (like aeroshell 100 plus).
The engine uses 1 qt. every 6-7 hours. Compressions are all over 75psi and usually at 78psi most of the cylinders.
Finally as a corrosion protection I also use CamGuard additive with the so called vapor phase anti corrosion.
This prevents any corrosion inside the engine and also keeps the valve guides clean. It is not uncommon having to ream the exhaust valve guides due to reduced clearances because of deposits coming mainly from oil contamination/degradation and poor cool downs.
I change the oil every 25 hours and the filter every 50 hours.
Hope this helps.