ASTM D6483 Standard Test Method for Evaluation of Diesel Engine Oils in T-9 Diesel Engine
11. Laboratory and Engine Test Stand Calibration/Non-Reference Requirements
11.1 Calibration Frequency - To maintain test consistency and severity levels, engine test stand calibration is required at regular intervals. The frequency of calibration is dependent on the laboratories' previous calibration experience or at the discretion of the TMC.

11.2 Calibration Reference Oils:
11.2.1 The reference oils used to calibrate T-9 test stands have been formulated or selected to represent specific chemical types or performance levels, or both. They can be obtained from the TMC. The TMC will assign reference oils for calibration tests. These oils are supplied under code numbers (blind reference oils).

11.2.2 Reference Oils Analysis - Do not submit reference oils to physical or chemical analyses for identification purposes. Identifying the oils by analyses could undermine the confidentiality required to operate an effective blind reference oil system. Therefore, reference oils are supplied with the explicit understanding that they will not be subjected to analyses other than those specified within this procedure unless specifically authorized by the TMC. In such cases where analyses are authorized, supply written confirmation of the circumstances involved, the data obtained, and the name of the person authorizing the analysis to the TMC.

11.3 Test Numbering - Number each T-9 test to identify the test stand number, the test stand run number, engine serial number, and engine h at the start of the test. The sequential stand run number remains unchanged for reruns of aborted, invalid, or unacceptable calibration tests. However, follow the sequential stand run number by the letter A for the first rerun, B for the second, and so forth. For calibration tests, engine h shall be zero. For non-reference tests, engine h are the test h accumulated since last reference. For example, 58-12A-2H0380-0 defines a test on stand 58 and stand run 12 as a calibration test, which was run twice on engine 2H0380 (serial number). A test number of 58-14-2H0380-500 defines a test on stand 58 and stand run 14 as a non-reference oil test on engine 2H0380, which has run 500 h since the last reference.

11.4 New Laboratories and New Test Stands:
11.4.1 Anew laboratory is defined as any laboratory that has never previously calibrated a test stand under this test method or has not calibrated a test stand within two years from the end of the last successful calibration test. All stands at a new laboratory are considered new stands.

11.4.2 A new stand is defined as an engine, dynamometer/cell, and support hardware that has never previously been calibrated under this test method or has not been calibrated within two years from the end of the last successful calibration test on that stand. A new engine in an existing test stand only requires one successful calibration test.

11.4.3 A new test stand shall have two acceptable calibration tests to be considered calibrated.

11.5 Test Stand and Engine Calibration:
11.5.1 Test Stand Calibration - Perform a calibration test on a reference oil assigned by the TMC after one year or 5000 h of non-reference test time (whichever comes first) have elapsed since the completion of the last successful calibration test. A non-reference test may be started provided at least one h remains in the calibration period. It is permissible to calibrate two engines in a single test stand. An unsuccessful calibration test voids any current calibration on the test stand and the associated engine.

11.5.2 Engine Calibration - Perform a calibration test on a reference oil assigned by the TMC after two years, 5000 h of non-reference test time, or one year of idle nontest conditions (whichever comes first) have elapsed since the completion of the last successful calibration test. A non-reference test may be started provided at least 1 h remains in the calibration period.

11.5.3 The TMC may schedule more frequent calibration tests at their discretion.

11.5.4 If nonstandard tests are conducted on a calibrated test stand, the TMC may require the test stand to be recalibrated prior to running standard tests.

11.5.5 The TMC may extend calibrations at their discretion.

11.6 Test Results:
11.6.1 The specified test results are average top ring weight loss (mg), adjusted average liner wear (µm), and Δlead (ppm).

11.6.2 Average Top Ring Weight Loss:
11.6.2.1 Examine the top rings for flaking. Remove any rings that exhibit flaking as observed by the unaided eye from the average top ring weight loss calculation. Report flaked rings (see Annex A1).

11.6.2.2 Use Practice E 178, two-sided test at a 95 % significance level, to determine if any of the top ring weight loss values are outliers. Report outlier rings (see Annex A1).

11.6.2.3 Calculate the average top ring weight loss, using all rings that do not exhibit flaking and are not considered outliers. Use a minimum of three rings to calculate average top ring weight loss. Ifmore than two rings exhibit flaking, consider the test noninterpretable as per the minimum of four cylinder liners needed for liner wear measurements (refer to 11.6.3.3).

11.6.3 Adjusted Average Liner Wear:
11.6.3.1 For each top ring that exhibits flaking, remove the corresponding cylinder liner from the average liner wear calculation. Report the affected cylinder liners (see Annex A1).

11.6.3.2 Use Practice E 178, two-sided test at a 95 % significance level, to determine ifany of the cylinder liner wear step values are outliers. Report outlier cylinder liners (see Annex A1).

11.6.3.3 Calculate the average cylinder liner wear step, using all cylinder liners that are not considered outliers and for which the top ring did not exhibit flaking. Use a minimum of four cylinder liners to calculate the average cylinder liner wear. If, due to ring flaking, less than four liners are available, then consider the test noninterpretable. If, due to ring flaking, exactly four liners are available, then do not screen for outliers as described in 11.6.3.2 and report the measured average cylinder liner wear step as the outlier screened average cylinder liner wear step.

11.6.3.4 Calculate adjusted average liner wear (ALW) in accordance with the following:
ALW = ACLW + 10.46(1.75 - SOOTAVG)µm
where:
ACLW = outlier screened average cylinder liner wear step, µm, and
SOOTAVG = arithmetic average of the ten soot measurements from 75 to 500 h.

Note that SOOTAVG shall be no less than 1.5 and no greater than 2.4. For calculated SOOTAVG values outside this range, these limiting values shall be used in the ALW calculation.

11.6.4 ΔLead:
11.6.4.1 ΔLead results are adjusted to account for any upper rod bearing weight loss outliers.
(1) Calculate the measured average upper rod bearing weight loss and report the value (see Annex A1).
(2) Use Practice E 178, two-sided test at a 95 % significance level, to determine if any rod bearing weight loss values are outliers. Report the outlier screened average upper rod bearing weight loss (see Annex A1). If no outliers were identified, this value will be identical to the measure value calculated in 11.6.4.1 (1).

11.6.4.2 Calculate Δ lead in accordance with the following:
Δlead = (lead500 - leadNEW) x (OABWLU/ABWLU)
where:
lead500 = lead content of the 500 h oil sample, ppm,
leadNEW = lead content of the new oil sample, ppm,
ABWLU = as measured upper rod bearing weight loss, mg, and
OABWLU = outlier screened upper rod bearing weight loss, mg.

11.7 Reference and Non-Reference Oil Test Requirements:
11.7.1 All operationally valid tests shall produce a TGA soot level between 1.5 and 2.0 % inclusive at 75 h. Any test that misses the 75-h soot window is considered operationally invalid. A lab should terminate a test that has missed the 75-h soot window.
11.7.1.1 Injection timing can be adjusted any time within the first 75 h to meet the 75-h soot window. However, during the first 75 h, do not adjust injection timing more than +/- 5° from the initial injection timing.

11.7.2 Calibration acceptance is determined in accordance with the Lubricant Test Monitoring System (LTMS) as administered by the TMC.

11.7.3 Fixed candidate oil pass criteria are published in Specification D4485. This test method may also be included in other specifications, that may contain criteria other than those in Specification D4485.

11.8 Non-Reference Oil Test Result Severity Adjustments - This test method incorporates the use of a severity adjustment (SA) for non-reference oil test results. A control chart technique, described in the LTMS, has been selected for identifying when a bias becomes significant for average top ring weight loss, adjusted cylinder liner wear, and Δ lead at EOT. When calibration test results identify a significant bias, a SA is determined in accordance with LTMS. Report the SA value (see Annex A1) in the space for SA. Add this SA value to non-reference oil test results, and enter the adjusted result in the appropriate space. The SA remains in effect until a new SA is determined from subsequent calibration test results, or the test results indicate the bias is no longer significant. Calculate and apply SAs on a laboratory basis.