MolaKule
Staff member
Back to the question.
Here is an excerpt from the ASTM D4742 Test:
Quote:
This test method is useful for screening formulated oils prior to engine tests. Within similar additive chemistry and base oil types, the ranking of oils in this test appears to be predictive of ranking in engine tests. When oils having completely different additive chemistry or base oil type are compared, oxidation stability results may not reflect the actual engine test result.
Other oxidation stability test methods have demonstrated that soluble metal catalyst supplies are very inconsistent and they have significant effects on the test results. Thus, for test comparisons, the same source and same batch of metal naphthenates shall be used.
1. This is a bench test to be used before actual in situ engine tests.
2. The test is valid IF the same base oil and similar additive packages are used. It is NOT valid for different base oil and dissimilar additive packages.
3. Here is a way that one could influence the test. One can vary the amount of catalyst. So what is the catalyst?
Quote:
...utilizes a high pressure reactor pressurized with oxygen along with a metal catalyst package, a fuel catalyst, and water in a partial simulation of the conditions to which an oil may be subjected in a gasoline combustion engine.
A good independent test lab would use the same batch of catalyst and the same amount of catalyst for eact test run.
In my view,
A. The ASTM D4742 test is a valid Bench Test when used with similar base oils and additive packages
B. The ASTM D4742 test is a valid Bench Test when the catalyst used is the same batch and the exact amount of catalyst is used for each oil.
In my opinion, this test does not say anthing about mineral oils being better than synthetics or vice versa, and here is why. A mineral oil could have more or different anti-oxidants in its additive package which could influence the oxygen uptake rate.
Here is an excerpt from the ASTM D4742 Test:
Quote:
This test method is useful for screening formulated oils prior to engine tests. Within similar additive chemistry and base oil types, the ranking of oils in this test appears to be predictive of ranking in engine tests. When oils having completely different additive chemistry or base oil type are compared, oxidation stability results may not reflect the actual engine test result.
Other oxidation stability test methods have demonstrated that soluble metal catalyst supplies are very inconsistent and they have significant effects on the test results. Thus, for test comparisons, the same source and same batch of metal naphthenates shall be used.
1. This is a bench test to be used before actual in situ engine tests.
2. The test is valid IF the same base oil and similar additive packages are used. It is NOT valid for different base oil and dissimilar additive packages.
3. Here is a way that one could influence the test. One can vary the amount of catalyst. So what is the catalyst?
Quote:
...utilizes a high pressure reactor pressurized with oxygen along with a metal catalyst package, a fuel catalyst, and water in a partial simulation of the conditions to which an oil may be subjected in a gasoline combustion engine.
A good independent test lab would use the same batch of catalyst and the same amount of catalyst for eact test run.
In my view,
A. The ASTM D4742 test is a valid Bench Test when used with similar base oils and additive packages
B. The ASTM D4742 test is a valid Bench Test when the catalyst used is the same batch and the exact amount of catalyst is used for each oil.
In my opinion, this test does not say anthing about mineral oils being better than synthetics or vice versa, and here is why. A mineral oil could have more or different anti-oxidants in its additive package which could influence the oxygen uptake rate.
Last edited:
