SH/T 0760-2005 Performance evaluation of diesel engine oils (Mack T-8 method)

Summary page. This page is a compiled excerpt/summary of the standard — it is not the full standard text and does not replace it. Verify every value against the official standard and the product certificate before use.

SH/T 0760-2005, abbreviated as the Mack T-8 method, evaluates the viscosity increase performance of diesel engine oils at a defined soot content; it also provides the T-8A and T-8E test methods.

Evidence note: the content of this page was compiled from the original text of this standard held in the Origin Standard library (points marked "[to be verified]" are "[source unclear]" in the original); for individual values and current status, refer to the original pages of the standard and the product certificate.

Scope: This standard test method is abbreviated as the Mack T-8 method and applies to the evaluation of the viscosity increase performance of diesel engine oils at a defined soot content. 1.2 This standard also provides the T-8A and T-8E test methods, which are completely identical to the T-8 test method except for Annex E and Annex F. 1.3 The numerical units in this standard use the SI system of units. Not applicable: not provided in the available material.

Principle: The test engine is a Mack E7-350 diesel engine. During the test the engine is first warmed up and flushed with engine oil for 2 h, after which the engine runs continuously at steady speed and load. The test duration is 300 h for reference oil tests and 250 h for non-reference oil tests. 4.2 During the test, oil samples are taken at intervals for viscosity and soot content analysis and the viscosity increase is calculated; linear interpolation is used to determine and calculate the viscosity increase value at a soot content of 3.8%. 4.3 Depending on the condition of the test engine, it is decided whether the engine is to be reassembled. When reassembling, the power-producing parts of the engine are disassembled, cleaned with solvent naphtha and measured. New standard parts shall be used for pistons, piston rings, cylinder liners and valve guides (see Table 2). 4.4 Clean the engine crankcase with solvent naphtha and replace worn or damaged parts. 4.5 The test bench is equipped with suitable auxiliary equipment to control engine speed, load and the various test parameters. 5.1 This method uses a turbocharged, intercooled four-stroke diesel engine to evaluate the viscosity change performance of engine oils. 5.2 This method may be used for specification approval of engine oils.

Apparatus: Test engine (Mack E7-350): in-line six-cylinder, turbocharged, intercooled, direct-injection compression-ignition four-stroke diesel engine. Bore 124 mm, stroke 165 mm, displacement 12 L. Rated power 261 kW at an engine speed of 1800 r/min. 6.1.2 The laboratory shall be clean and dust-free; the air in the engine assembly room is recommended to be filtered and the temperature and humidity controlled. 6.2.1 Mack test engine: available from Mack Trucks; the parts required for the test are given in Table 2. 6.2.2 Engine cooling system: a pressurized closed system consisting of a heat exchanger, a coolant storage tank and an outlet temperature control valve; the coolant tank is pressurized to a system pressure of 103 kPa; a glass sight window is fitted; the thermostat is fully open. 6.2.3 Engine oil system: schematic diagrams see Figures B.7 and B.8 in Annex B. 6.2.4 Auxiliary oil system: 9.5 L closed weighing tank, auxiliary oil pump flow 5.7 L/min±1.9 L/min; oil suction line 1 and oil return line 2 are oil-resistant rubber hoses of 13 mm and 10 mm internal diameter respectively; the internal diameter of connecting line 3 is not less than that of the suction line. 6.2.5 Crankcase evacuation system: squirrel-cage type extractor fan. 6.2.6 Blow-by meter: exhaust-type gas flowmeter or an instrument of equivalent function, to measure blow-by flow. 6.2.7 Intake air supply and filtration system: intake air filter with initial efficiency 99.2%; replace the filter element when the pressure difference reaches 2.5 kPa. 6.2.8 Fuel supply system: with heating and cooling functions; the recommended system is shown in Figure B.9 of Annex B. 6.2.9 Intake manifold temperature control: controlled by the intercooler (see Figure B.10 of Annex B). 8.6.1 Calibration equipment: thermocouples, pressure gauges, engine speed and fuel flow measuring equipment. 8.6.2 Temperature measurement: thermocouples and digital display instruments or equipment of equivalent function; thermocouple range 0 °C–150 °C, error ±0.5 °C at 10 °C±1 °C, error ±0.5 °C at 0 °C±1 °C. 8.6.3 Pressure measurement: pressure sensors (locations of the measuring points see 8.6.3.1–8.6.3.8). 8.6.4 Blow-by meter: installed at the blow-by outlet of the crossover pipe of the rocker cover. 8.6.5 Fuel consumption measuring equipment: installed in the fuel line before the primary filter. 8.6.6 Humidity measuring equipment: installed between the intake air filter and the turbocharger. Annex C Soot (TGA) analysis: thermogravimetric analyser, shaker, sample pan. Table 2 New parts used in engine assembly: | No. | Part name | Quantity | Part number | |---|---|---|---| | 1 | Cylinder liner | 6 | [source unclear] in the original ([to be verified] [source unclear]) | | 2 | Piston crown/skirt | 6 | [source unclear] in the original ([to be verified] [source unclear]) | | 3 | Piston rings: first ring/second ring/oil ring | 6/6/6 | [source unclear] in the original ([to be verified] [source unclear]) | | 4 | Gaskets | [source unclear] in the original | [source unclear] in the original ([to be verified] [source unclear]) | | 5 | Full-flow oil filter/filter centrifugal element | 2/1 | [source unclear] in the original ([to be verified] [source unclear]) | | 6 | Engine coolant regulator | 1 | [source unclear] in the original ([to be verified] [source unclear]) | | 7 | Primary fuel filter | 1 | [source unclear] in the original ([to be verified] [source unclear]) | | 8 | Secondary fuel filter | 1 | [source unclear] in the original ([to be verified] [source unclear]) | | 9 | Valve guide/valve guide seal | 24/24 | [source unclear] in the original ([to be verified] [source unclear]) | Note: the part numbers in Table 2 are severely [source unclear] and cannot be reliably reconstructed; all are marked [to be verified].

Reagents and reference materials: Test oil: about 151 L of test oil is required per test. 7.1.2 Fuel: the recommended fuel quality specifications are given in Table 1 (low-sulfur diesel fuel). 7.1.3 Engine coolant: softened or distilled water with a salt content less than 0.03 g/L (without any additives). 7.2 Cleaning material: solvent naphtha is used as the cleaning material for engine parts. Annex C Gases for soot (TGA) analysis: nitrogen purity not less than 99.99%; oxygen purity not less than 99.99%. 10.13.1 Post-test flush oil: Bulldog Premium Oil or a flush oil of equivalent function. Table 1 Technical requirements for T-8 test fuel: | Test item | Quality specification | Test method | |---|---|---| | Sulfur content/% (mass fraction) | 0.03–0.05 | GB/T 11140 | | Density (20 °C)/(g/cm³) | 0.8406–0.8617 | SH/T 0604 | | Composition/% (volume fraction), aromatic content | 28–35 | SH/T 0606 | | Composition/% (volume fraction), olefin content | Report | SH/T 0606 | | Composition/% (volume fraction), saturated hydrocarbon content | Report | SH/T 0606 | | Cetane index | Report | GB/T 11139 | | Cetane number | 42–48 | GB/T 386 | | Copper strip corrosion (50 °C, 3 h)/grade, max. | 3 | GB/T 5096 | | Flash point/°C, min. | 54 | GB/T 261 | | Cloud point/°C, max. | −12 | GB/T 6986 | | Pour point/°C, max. | −17 | GB/T 3535 | | Carbon residue of 10% distillation residue/% (mass fraction), max. | 0.35 | GB/T 268 | | Water and sediment/% (volume fraction), max. | 0.05 | SH/T 0064 | | Ash/% (mass fraction), max. | 0.01 | GB/T 508 | | Kinematic viscosity (40 °C)/(mm²/s) | 2.0–3.2 | GB/T 265 | | Distillation/°C, initial boiling point | 177–199 | GB/T 6536 | | Distillation/°C, 10% recovery temperature | 210–232 | GB/T 6536 | | Distillation/°C, 50% recovery temperature | 249–277 | GB/T 6536 | | Distillation/°C, 90% recovery temperature | 299–327 | GB/T 6536 | | Distillation/°C, final boiling point | 327–360 | GB/T 6536 | Note: in Table 1 the density test method is [source unclear] in the original (printed as "S11/T" followed by illegible characters) and has been checked against SH/T 0604 ([to be verified] [source unclear]); the composition test method is [source unclear] in the original (printed as "sw 1" followed by illegible characters) and has been checked against SH/T 0606 ([to be verified] [source unclear]); the water and sediment test method is [source unclear] in the original (printed as "SH/T" followed by illegible characters and "164") and has been checked against SH/T 0064 ([to be verified] [source unclear]).

Key conditions: Table 4 Test operating conditions: | Parameter | Operating condition | |---|---| | Time/h | 250 (300 for reference oil tests) | | **Controlled parameters** | | | Speed/(r/min) | 1800±5 | | Fuel flow/(kg/h) | 63.3%±1.0% (as in the original, suspected to be 63.3±1.0, [to be verified] [source unclear]) | | Intake manifold temperature/°C | 43±3 | | Jacket coolant outlet temperature/°C | 85±3 | | Fuel inlet temperature/°C | 40±1 | | Intake air temperature/°C | 25±3 | | Crankcase pressure/kPa | 0.50±0.25 | | Intake air pressure/kPa | 2.50±0.25 | | Exhaust back pressure/kPa | 3.1±0.4 | | **Non-controlled parameters** | | | Torque/(N·m) | 1369–1398 | | Exhaust temperature/°C, before turbine | 602–632 | | Exhaust temperature/°C, tail pipe | 455–474 | | Intake manifold pressure/kPa | 186–199 | | Oil temperature/°C | 100–107 | | Main oil gallery pressure/kPa | 372–441 (for SAE 15W/40 oil; other viscosity grades will give different results) | | Intercooler differential pressure ΔP/kPa | not more than 13.6 | | Oil filter differential pressure ΔP/kPa | not more than 138 (if exceeded, replace both full-flow filters) | Table 3 Oil flush and break-in operating conditions (severely damaged in the original ([source unclear]); only part is legible): | Parameter | Break-in (new or reassembled engine) | Pre-test oil flush | |---|---|---| | Time/h | [source unclear] in the original ([to be verified] [source unclear]) | [source unclear] in the original ([to be verified] [source unclear]) | | Speed/(r/min) | [source unclear] in the original ([to be verified] [source unclear]) | [source unclear] in the original ([to be verified] [source unclear]) | | Load | [source unclear] in the original ([to be verified] [source unclear]) | [source unclear] in the original ([to be verified] [source unclear]) | Note: the legible numerical fragments in Table 3, such as "1200", "1384", "1250" and "1731", cannot be reliably assigned to parameters and are all marked [to be verified].

Calculation and results: Linear interpolation is used to determine and calculate the viscosity increase value at a soot content of 3.8%. 10.7 Oil consumption calculation, formula (1): Oil consumption (g/kW·h) = (FW − W)/(25P) where: FW—mass at full scale of the oil, g; W—the oil mass displayed by the weighing system n hours before each oil addition, sampling and oil drain, g; P—engine brake output power, kW. The reported oil consumption is the average oil consumption over a 25 h period. If the oil consumption over a 25 h period is greater than 0.225 g/kW·h, the full-scale oil value shall be re-determined. 10.12 Calculation of the differential pressure ΔP of the centrifugal oil filter, formula (2): ΔP = ΔP maximum − ΔP initial where: ΔP maximum—maximum differential pressure across the oil filter, kPa; ΔP initial—differential pressure across the oil filter just after entering the test conditions, kPa. If the filter has been replaced, add the ΔP before replacement to the ΔP after replacement; if a shutdown has occurred, add the ΔP after the shutdown to the ΔP before the shutdown. 11.3 Total oil consumption: under normal conditions it shall be less than or equal to 0.182 g/kW·h; for a calibration test, a total oil consumption greater than 0.304 g/kW·h is abnormal and the test is invalid. Annex C.2 Calculation of soot content: the difference between the mass of the oil sample after stabilization at 650 °C and the mass after stabilization at 750 °C is the soot content of the sample; dividing this by the total amount of the analysed oil sample gives the percentage soot content in the oil, to 0.1% (mass fraction). Annex E.3.2 Calculation of the T-8A viscosity increase rate: Viscosity increase rate (150 h–100 h) = (VIS150 − VIS100)/50 where: VIS150—kinematic viscosity (100 °C) of the test oil at 150 h, mm²/s; VIS100—kinematic viscosity (100 °C) of the test oil at 100 h, mm²/s. Annex F.4 Calculation of T-8E relative kinematic viscosity: RV4.8 = 2(VIS4.8)/(V0 + Vs) where: RV4.8—relative kinematic viscosity of the test oil at a soot content of 4.8%; VIS4.8—kinematic viscosity of the test oil at a soot content of 4.8%, mm²/s; V0—kinematic viscosity at 100 °C of the unsheared test oil, mm²/s; Vs—kinematic viscosity at 100 °C of the test oil after shearing, mm²/s.

Quality control: Repeatability (r): the difference between two valid test results obtained by the same laboratory on the same oil under correct and normal operating conditions shall not exceed the values listed in Table 5. 13.2 Reproducibility (R): the difference between two separate valid test results obtained by different laboratories on the same oil under correct and normal operating conditions by different operators shall not exceed the values listed in Table 5. Table 5 Precision: | Parameter | Repeatability | Reproducibility | |---|---|---| | Viscosity increase value at 3.8% TGA soot content/(mm²/s) | 2.80 | 2.83 | Annex E Table E.1 T-8A precision: | Parameter | Repeatability | Reproducibility | |---|---|---| | Viscosity increase rate from 100 h to 150 h/(mm²/s·h) | 0.023 | 0.024 | Annex F Table F.2 T-8E precision: | Parameter | Repeatability | Reproducibility | |---|---|---| | Relative kinematic viscosity at 4.8% soot (TGA) content | 0.64 | 0.74 |

Normative references: GB/T 261 Petroleum products — Determination of flash point (closed cup method) (GB/T 261-83(91), eqv ISO 2719:1973) GB/T 265 Petroleum products — Determination of kinematic viscosity and calculation of dynamic viscosity GB/T 268 Petroleum products — Determination of carbon residue (Conradson method) (GB/T 268-1987, eqv ISO 6615:1983) GB/T 386 Determination of ignition quality of diesel fuels (cetane number method) GB/T 508 Petroleum products — Determination of ash (GB/T 508-1985(1991), eqv ISO 6245:1982) GB/T 3535 Petroleum — Determination of pour point (GB/T 3535-83(91), eqv ISO 3016:1974) GB/T 5096 Petroleum products — Copper strip corrosion test GB/T 6536 Petroleum products — Determination of distillation GB/T 6986 Petroleum — Determination of cloud point (GB/T 6986-86(91), eqv ISO 3015:1974) GB/T 11137 Dark petroleum products — Determination of kinematic viscosity (reverse-flow method) and calculation of dynamic viscosity GB/T 11139 Distillate fuels — Calculation of cetane index GB/T 11140 Petroleum products — Determination of sulfur content (X-ray spectrometry) GB/T 17476 Used lubricating oils — Determination of additive elements, wear metals, contaminants and selected elements in base oils (inductively coupled plasma emission spectrometry) SH/T 0064 Distillate fuels — Test method for free water and particulate contaminants SH/T 0604 Crude petroleum and petroleum products — Determination of density (U-tube oscillation method) SH/T 0606 Middle distillates — Determination of hydrocarbon types (mass spectrometry)

Evidence note: [to be verified] and [source unclear] mark specific points that still require checking against the original text of the standard and do not indicate that they have been verified. Do not use these values or steps directly as a basis for work.

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