dnewton3
Staff member
I would agree that excessive oxidation is undesirable and to be avoided. But not all effects of oxidation are bad.
Oxidation is the building block of the TCF, and proven to be very beneficial in reducing wear.
www.sae.org
This study shows that the establishment of TCF, and subsequent thickening of the film barrier layers from continued lube use, is very directly affecting wear.
- the study showed direct correlation of TCF thickness to wear rates
- the study showed direct correlation of TCF thickness to valvetrain friction reduction
- the study did not show correlation between wear rate changes and viscosity changes
I will remind you all that without correlation, there can be no causation.
Like most things in life, moderation is the key. I certainly don't want my lube to turn into molasses and leave behind pounds of sludge. But study data clearly shows that lubes do very well in extended OCIs because of this TCF; this oxidation barrier that keeps wear rates very, very low under the right conditions. Simply put, some amount of oxidation is very good, too much is very bad.
Engines that run fairly clean, don't have intense "hot spots" which would cause localized coking, etc, can benefit from long OCIs. Nearly all engines I've studied in my database (over 25k UOAs) have shown the effect of lower wear rates as the OCI extends; that is a direct benefit of the oxidation TCF being allowed to mature.
Oxidation is the building block of the TCF, and proven to be very beneficial in reducing wear.
The Effect of Oil Drain Interval on Valvetrain Friction and Wear
Engine oils are subjected to a series of industry standard engine dynamometer tests to measure their wear protection capability, sludge and varnish formation tendencies, and fuel efficiency among several other performance attributes before they are approved for use in customer engines. However, thes
- the study showed direct correlation of TCF thickness to wear rates
- the study showed direct correlation of TCF thickness to valvetrain friction reduction
- the study did not show correlation between wear rate changes and viscosity changes
I will remind you all that without correlation, there can be no causation.
Like most things in life, moderation is the key. I certainly don't want my lube to turn into molasses and leave behind pounds of sludge. But study data clearly shows that lubes do very well in extended OCIs because of this TCF; this oxidation barrier that keeps wear rates very, very low under the right conditions. Simply put, some amount of oxidation is very good, too much is very bad.
Engines that run fairly clean, don't have intense "hot spots" which would cause localized coking, etc, can benefit from long OCIs. Nearly all engines I've studied in my database (over 25k UOAs) have shown the effect of lower wear rates as the OCI extends; that is a direct benefit of the oxidation TCF being allowed to mature.
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