From Lube-Tips newsletter published by Noria Corporation
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Q & A: Engine Oil Performance Testing
"I have seen a number of lubricant manufacturers refer to the four-ball
wear scar test as an indicator of how well the oil will protect an engine.
Other larger companies tend to brush off the results of this test indicating
that it isn't representative of actual engine conditions adding that because
it is cheap to run, the results aren't worth much.
What are your thoughts on this?"
The four-ball test (ASTM D4172) is often used as a screening test for many
different lubricant types that contain antiwear additives or similar base oil
properties. Other tribo-mechanical bench tests are often used as well,
including the Timken Test (ASTM D2782) and the Pin and V-Block
(ASTM D2670). Because engines have different contact geometry, loads,
metallurgy and speeds, numerous bench tests and test protocols are needed.
It is not uncommon for several oils to be tested using two such methods and
to find that the performance rankings between the oils to reverse (no
correlation).
This is why, among other reasons, passenger car motor oils and heavy-duty oils
(diesel crankcase) are tested in actual engines using controlled methods such as
ASTM D5533 Sequence IIIF D5302 Sequence VE.
Jim Fitch, Noria Corporation
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Just a FYI,
Bryan
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