approx engine run time for sample 1,000 hours
RNT (Radionuclide Test) says otherwise.
The highest rates of wear (generation of fe) occur immediately after an oil change.
Increasing the frequency of the activation cycles of the oil in a specific engine increases the total amount of wear over the life of the motor.
Brand new oil as a rule is creating iron at the rate of 5-10ppm per 1000 miles, at 2000 miles thru 10,000 miles that wear rate drops to anywhere between .5 to 3 ppm per 1000 miles. Only when the oil has 15,000 - 20,000 miles on does the wear rate increase to what the oil was permitting when new. This is based on an engine operating in optimal condition.
Engines with issues such as excessive soot formation dictates more frequent changes in order to keep the soot levels as low as possible.
Reducing the frequency of changes improves the stability of the additive protection within the motor. Also it allows the additives to become fully active by virtue of heat and pressure as well as to place the additives at the high pressure regions of the motor.
High pressure additives require as much as 1,000 to 3,000 miles to become fully active and stable in the motor before they provide optimal levels of protection. This is partly due to the longer life expectency of modern lubricants in extended drain intervals.
Oil additives because of the relative low concentration require multiple passes and running cycles to fully activate in the motor. This period of time depends on running time and cycles that result in the motor reaching full operating temperature.
DB