SH/T 0783-2005 Evaluation method for high-temperature oxidation and anti-wear performance of internal combustion engine oils (CEPT- III method)

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Incomplete source card: Sections 10, 11, 12, 13, 14 are absent from the available source. Only available content is translated; source completion is pending.

Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: SH/T 0783—2005
• Chinese full name: Evaluation method for high-temperature oxidation and anti-wear performance of internal combustion engine oils (CEPT- III method)
• English name (original title page): Test method for evaluation of automotive engine oils for inhibition of oxidization and wear under high-temperature conditions (CEPT- II method)
  • Requires confirmation against the source standard (source-text extraction): the English parentheses on the title page contain “CEPT- II method”, which is inconsistent with the Chinese title “CEPT- III method” and the multiple occurrences of “CEPT- III method” in the main text; suspected to be source-text extraction or a typographical error in the original text.
• Replacement relationship: not provided in the available source (the foreword does not list replaced standards).
• Publication/implementation: published on 2005-11-28, implemented on 2006-06-01.
• Publishing unit: National Development and Reform Commission of the People's Republic of China.
• Technical committee: Sinopec Research Institute of Petroleum Processing.
• Drafting unit: Sinopec Research Institute of Petroleum Processing.
• Main drafters: Li Shaoyu, Liu Shuntao, Lu Wentong, Wang Qingxin, Wang Dianfu, Wei Rongtian, Yang Benfeng, Zhao Yancheng.
• Nature of appendices: Appendix A and Appendix B are normative appendices; Appendix C, Appendix D, Appendix E, Appendix F, and Appendix G are informative appendices.

2. Scope of application and non-applicability

• 1.1 This standard specifies the method for evaluating the tendency of internal combustion engine oils to undergo high-temperature oxidative thickening, formation of deposits such as high-temperature sludge and varnish, and their anti-wear performance.
• 1.2 This standard applies to the performance evaluation of gasoline engine oils (such as: SE, SF) and the related performance evaluation of diesel engine oils.
• Non-applicability: not provided in the available source.

3. Method principle

• 4 Method summary: Before each test, disassemble the engine, thoroughly clean the engine parts with solvent naphtha, and install new engine parts according to the method requirements. Install the assembled engine on a bench that can control speed, load, and other engine operating parameters. Add test oil to the engine, start the engine, perform the 10min timed operation, and adjust the ignition timing angle. After the timed operation, perform the 3.5h engine break-in operation. After the break-in operation, the engine undergoes the 64h formal test under high-temperature and high-speed conditions, with 8h as one cycle.
• After the 10min timed operation and after every 8h of the 64h formal test, take analytical oil samples and measure the 40℃ kinematic viscosity of the samples at each stage. Based on the viscosity of the oil sample from the 10min timed operation, calculate the viscosity increase rate of the oil samples at each stage.
• At the end of the test, disassemble the engine, evaluate deposits such as sludge and varnish as specified, and measure the components.
• 5 Significance and use:
  • 5.1 This test method is an engine test method for evaluating the oil thickening and anti-wear performance of internal combustion engine oils under high-temperature and high-speed conditions.
  • 5.2 The oil thickening referred to in this method is the viscosity increase of the oil caused by high-temperature oxidation. In actual use, oil thickening will reduce the pumping performance of the oil pump, thereby causing damage to the various transmission components of the engine.
  • 5.3 The deposit rating results show the tendency of deposits to form in the engine, including causing piston rings to stick in the ring grooves and tappets to stick. Ring sticking will reduce engine compression and lead to a decrease in engine power. Tappet sticking will increase wear of transmission components and produce noise.
  • 5.4 This standard has good correlation with SH/T 0513 Evaluation method for high-temperature oxidation and wear of internal combustion engine oils (MS Procedure III D method).

4. Reagents and materials (purity / preparation)

• 10.1 Fuel: special leaded gasoline, whose specifications are given in Appendix A; approximately 1200L is required for each test.
• 10.2 Engine parts cleaning agent: 190 solvent naphtha conforming to GB 1922.
• 10.3 Cleaning agent for engine and rocker cover cooling system: sodium sulfate (analytical grade), trisodium phosphate (analytical grade).
• 10.4 Carburetor cleaning agent: commercially available carburetor cleaner.
• 10.5 Engine assembly oil: test oil.
• 10.6 Sealants: thread-locking sealant; anaerobic pipe thread sealant; silicone rubber flat sealant.
• 10.7 Exhaust bolt thread anti-seize lubricant: 7451 high-temperature thread lubricant.
• 10.8 Test oil: each test requires at least test oil 1? L (requires confirmation against the source standard (source-text extraction), the original number is missing); generally 18L should be provided.
• 10.9 Coolant: ethylene glycol with additives, whose preparation method is given in Appendix B.
• Appendix A (normative appendix) Fuel quality indicators: Table A.1 Fuel quality indicators, including items such as antiknock performance, research octane number (RON), tetraethyl lead content, distillation range, vapor pressure, existent gum, induction period, sulfur content, copper strip corrosion (50℃, 3h), water-soluble acids, acidity, mechanical impurities and water, doctor test, composition (paraffinic and naphthenic hydrocarbon content, olefin content, aromatic hydrocarbon content); Note: during fuel blending, substances such as detergents and other antiknock agents are allowed to be added. For specific indicator values and test methods, see Table A.1 in the original text (source-text extraction many values in the table are garbled; requires confirmation against the source standard (source-text extraction)).
• Appendix B (normative appendix) Preparation of coolant:
  • B.1 Additives and blending proportions: sodium nitrate (NaNO₃) 0.20% (mass fraction); sodium tetraborate (Na₂B₄O₇·5H₂O) 1.00% (mass fraction); sodium silicate (Na₂SiO₃·5H₂O) 0.15% (mass fraction); trisodium phosphate (Na₃PO₄·12H₂O) 0.45% (mass fraction); sodium benzotriazole (50% aqueous solution) 0.20% (mass fraction); sodium hydroxide (NaOH) 0.20% (mass fraction); nonionic surfactant or equivalent 0.02% (mass fraction); green dye 0.005% (volume fraction); water 2.00% (volume fraction).
  • B.2 Preparation method: First add the specified amount of sodium tetraborate to the weighed ethylene glycol and stir to dissolve. Slightly warm distilled water or softened water, add the specified amounts of sodium nitrate, sodium silicate, trisodium phosphate, and sodium hydroxide, and stir to dissolve. Pour the two solutions together, then add the specified amounts of sodium benzotriazole, dye, and surfactant. After preparation, there should be no insoluble matter.
  • B.3 Preparation of sodium benzotriazole: use 1.688kg of sodium benzotriazole, 0.597kg of sodium hydroxide, and 1.745kg of water. Dissolve the sodium hydroxide in water; after dissolution, add the sodium benzotriazole and stir until dissolved. If dissolution is insufficient, sodium hydroxide may be added and heated (the original text here source-text extraction is incomplete; requires confirmation against the source standard (source-text extraction)).

5. Instruments and equipment

• 6.3 Special instruments and equipment:
  • 6.3.1 Exhaust analyzer: an instrument for measuring the oxygen, carbon monoxide, and carbon dioxide contents in engine exhaust.
  • 6.3.2 Cam height measuring instrument: a dial indicator type measuring device or outside micrometer with an accuracy of 0.001mm.
  • 6.3.3 Weighing equipment: an analytical balance with an accuracy of 0.1mg.
  • 6.3.4 Spring testing machine: measures valve spring force.
  • 6.3.5 Surface roughness measuring instrument: measures the surface roughness of the honed cylinder inner surface. The measuring range of the instrument should be 0.2μm~0.5μm.
  • 6.3.6 Connecting rod heater: used to heat the small end of the connecting rod when installing the piston pin.
  • 6.3.7 Honing machine: hones the cylinder liner to ensure the inner diameter size and surface roughness of the cylinder liner.
  • 6.3.8 Timing flash lamp: an inductive timing flash lamp, used to measure ignition timing during engine operation.
  • 6.3.9 Cylinder liner inner diameter measuring positioning ruler: used for positioning when measuring the cylinder liner inner diameter.
  • 6.3.10 Piston ring measuring positioner: fixes the piston ring position in the cylinder when measuring piston ring end gap, to ensure the correct end gap.
  • 6.3.11 Grinding machine: used to adjust the end gap of compression rings.
  • 6.3.12 Cylinder block pressure plate: install this pressure plate during cylinder block measurement and honing to ensure the accuracy of cylinder block measurement and honing.
  • 6.3.13 Crankcase blow-by measuring instrument: used to measure crankcase blow-by. During measurement, the crankcase pressure should be adjusted to 0kPa~0.025kPa.
• 6.2 Test engine: the engine used for the test is the CA488 in-line 4-cylinder 4-stroke carbureted gasoline engine produced by China First Automobile Group Corporation. The compression ratio is 9.0:1, the displacement is 2.2L (requires confirmation against the source standard (source-text extraction); the original text “224” is suspected to be “2.2L”), the cylinder bore is 87.5mm, and the stroke is 92mm.
• 6.2.1 Engine component modifications:
  • 6.2.1.1 Carburetor: modify the BVP2UIAG or NbnG20 two-barrel carburetor, retaining the main barrel's power?, accelerator pump, enrichment device, float chamber, and idle system, and removing the load compensator (the original text source-text extraction is incomplete; requires confirmation against the source standard (source-text extraction)).
  • 6.2.1.2 Rocker cover: change the original engine rocker cover to a rocker cover with a cooling jacket machined from stainless steel plate.
  • 6.2.1.3 Oil pan: change the original engine oil pan to an oil pan machined from stainless steel plate with a locally deepened oil reservoir.
  • 6.2.1.4 Rocker cover inner baffle: change the original engine rocker cover inner baffle to a baffle machined from stainless steel plate.
  • 6.2.1.5 Oil filler and crankcase pressure measuring tube: install an oil filler tube with pressure measurement at the original engine fuel pump location.
  • 6.2.1.6 Flywheel timing indication: used to adjust the engine ignition timing angle.
  • 6.2.1.7 Distributor drive device: remove the pump body and inner rotor of the original engine oil pump.
  • 6.2.1.8 Intake manifold heat shield: to reduce heat radiated from the exhaust manifold to the intake manifold and rocker cover, install a heat shield between the intake and exhaust manifolds.
  • 6.2.1.9 Oil converter: remove the original engine oil filter and install an oil converter so that test oil from the external lubrication system enters the main oil gallery and excess oil returns to the oil pan.
• 6.1 Laboratory environment:
  • 6.1.1 The laboratory is clean and dust-free.
  • 6.1.2 Control the temperature and humidity of the engine component measurement area; the temperature should be controlled at 10℃~25℃ and the measurement temperature difference before and after the test should be within the range of 3℃; the humidity should be controlled at 45%~65% (relative humidity).
  • 6.1.3 Air filtration and humidity control (relative humidity 45%~65%) shall be provided for the engine assembly room to prevent dust from settling on part surfaces or rusting.
  • 6.1.4 When the engine is moved from the assembly room to the test room, appropriate measures shall be taken to prevent dust from entering the engine.
  • 6.1.5 During the test, a fan or other ventilation equipment shall not be used to blow directly onto the test engine.
  • 6.1.6 The test room shall not use lighting equipment with large heat output to directly illuminate the engine, nor shall thermal insulation be applied to the engine in order to control temperature.
  • 6.1.7 The parts rating environment shall meet the requirements of SH/T 0510.
  • 6.1.8 No specific provisions are made for the environment of the parts cleaning room. Because there is a large amount of solvent, good ventilation equipment shall be provided to ensure safety.

6. Recommended Operating Conditions

• 7 Temperature measurement and thermocouple installation positions:
  • 7.1 Temperature measurement: Use iron-constantan (J type) thermocouples or platinum resistance to measure temperature. Unless otherwise specified, all thermocouples shall be placed at the center of the medium flow stream.
  • 7.2 Thermocouple installation positions:
    • Engine coolant inlet temperature: within 350mm from the engine cylinder block inlet.
    • Engine coolant outlet temperature: within 200mm from the engine cylinder block outlet.
    • Engine oil inlet temperature: at the engine main oil gallery inlet.
    • Oil pan oil temperature: at the front part of the oil pan sump.
    • Intake air temperature: on the intake elbow in front of the carburetor.
    • Rocker cover coolant outlet temperature: at the coolant outlet on the left rear side of the jacketed rocker cover.
    • Exhaust temperature: at the outlet of the exhaust manifold.
    • Crankcase blowby outlet temperature: between the blowby condenser and the oil-gas separator.
    • Fuel temperature: at the carburetor float chamber inlet.
• 8 Pressure measurement and measurement positions:
  • 8.1 Pressure measurement: The measuring instruments and sensors must meet the control accuracy of the test conditions.
  • 8.2 Measurement positions:
    • Intake manifold pressure: on the intake manifold between cylinders 3 and 4.
    • Main oil gallery oil pressure: on the main oil gallery between cylinders 3 and 4.
    • Oil pressure after the oil pump: after the pump and before the filter.
    • Fuel pressure: before the carburetor fuel inlet.
    • Intake pressure: at the carburetor intake elbow.
    • Crankcase pressure: at the original engine cylinder block oil dipstick location.
    • Exhaust back pressure: 150mm below the exhaust manifold flange.
• 9 Test bench systems:
  • 9.1 Engine speed and load control system: The system shall be able to meet the test conditions specified in this test method. It is recommended to use a closed-loop system with an eddy current dynamometer to control engine speed, and the throttle to control engine load.
  • 9.2 Intake system: The system shall be able to provide air with a certain humidity, temperature, and pressure at a flow rate of 2500L/min to the engine intake inlet. Humidity control uses a dedicated humidity regulating device. The air temperature below the humidity measurement point shall be higher than the dew point temperature. The air delivery pipeline shall have insulation measures to prevent moisture in the air from condensing on the pipe wall and reducing the actual humidity of the intake air. Intake air temperature is controlled by an electric heater on the intake pipe. Intake air pressure is regulated by a pressure control valve on the intake pipe. The intake system must be equipped with an air filter to prevent dust and other debris from entering the carburetor.
  • 9.3 Exhaust system: The system shall be able to meet the exhaust back pressure requirement (103.5kPa±0.7kPa). The exhaust pipe is equipped with an exhaust gas sampling pipe and an exhaust back pressure measurement connector.
  • 9.4 Fuel system: Ensure that the fuel pressure at the carburetor fuel inlet is 30kPa±10kPa, and the fuel temperature is required to be below the initial boiling point of the fuel. The system shall be equipped with a filter and a fuel shut-off valve (located relatively close to the carburetor so that fuel can be cut off when the engine stops).
  • 9.5 Ignition system: Use the original engine ignition system.
  • 9.6 Lubrication system: Use an externally mounted pump driven by a motor. The system flow diagram is shown in Figure 1. The main oil gallery oil pressure is regulated by a pressure regulating valve. The oil temperature is heated by an electric heater to meet the test requirements. Components in the system that come into contact with the test oil shall not be made of copper.
  • 9.7 Cooling system:
    • 9.7.1 Engine cooling system: Use an externally mounted pump driven by a motor. The system flow diagram is shown in Figure 2. The coolant temperature is regulated by the water flow rate through the heat exchanger. The coolant flow rate is measured by an orifice flow meter and regulated by a control valve. The coolant is glycol with additives (see Appendix B).
    • 9.7.2 Rocker cover and blowby condenser cooling system: Use an externally mounted pump driven by a motor. The system flow diagram is shown in Figure 3. The coolant flows through the rocker cover and blowby condenser. The coolant flow rate is measured by an orifice flow meter and regulated by a control valve. The coolant is glycol with additives (see Appendix B).
  • 9.8 Crankcase ventilation system: Blowby flows out from the rocker cover, passes through the condenser and oil-gas separator, and is discharged into the atmosphere. Part of the blowby, after being cooled in the condenser, flows back as liquid to the rocker cover (the original text source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction)).
• 13.2 Break-in: Carry out break-in according to the conditions in Table 1. During break-in, adjust the ignition timing to 34° before top dead center. Adjust the oil pressure to 375kPa±25kPa. After break-in is completed, turn off the oil pump and replace the 75μm fine filter screen with the 115μm coarse filter screen. Then start the oil pump to expel air from the system, then turn off the oil pump. After stopping for 20min, check the oil level, and then proceed with the formal test.
• Table 1 Break-in conditions (source-text extraction table values are disordered; the following is the identifiable content, requires confirmation against the source standard (source-text extraction)):
  • Stage: 1, 2, 3, 4
  • Time, min: 15, 60, 45, (stage 4 requires confirmation against the source standard)
  • Speed, r/min: 1500, 1500, 3000, 800
  • Output torque, N·m: 10, 10, 90, 10
  • Main oil gallery oil pressure: >300, >300, 375±25, >300 (unit requires confirmation against the source standard)
  • Oil temperature, ℃: 70, 70, 45, 50
  • Engine coolant outlet temperature, ℃: (requires confirmation against the source standard)
  • Engine coolant flow rate, L/min: 100, 100, (requires confirmation against the source standard), (requires confirmation against the source standard)
  • Rocker cover coolant temperature, ℃: 50, 50, (requires confirmation against the source standard), (requires confirmation against the source standard)
  • Intake air temperature, ℃: 32, 32, 32, 32
  • Intake air pressure, kPa: 0.05, 0.05, 0.05, 0.05
  • Intake air humidity, g/kg: 11.4, 11.4, 11.4, 11.4
  • Exhaust back pressure, kPa (absolute): ≤103.5, ≤103.5, ≤103.5, ≤103.5
  • Ignition timing, °BTDC: 34, 34, 34, 34
• 13.3 Formal test: Start the engine. When the oil temperature reaches 148℃±1℃, start timing. The formal test totals 64h, which includes 8 cycles, each cycle being 8h. The formal test conditions are shown in Table 2.
• Table 2 Formal test conditions:
  • Speed, r/min: 3000±25
  • Output torque, N·m: 110±2
  • Main oil gallery oil pressure, kPa: not less than? (original value missing, requires confirmation against the source standard (source-text extraction))
  • Oil temperature, ℃: 148±1
  • Engine coolant outlet temperature, ℃: 118±1
  • Engine coolant flow rate, L/min: 75±2
  • Rocker cover coolant outlet temperature, ℃: ?/12±1 (original text source-text extraction is disordered, requires confirmation against the source standard (source-text extraction))
  • Blowby condenser coolant flow rate, L/min: (requires confirmation against the source standard (source-text extraction))
  • Intake air temperature, ℃: 32±1
  • Intake air pressure, kPa: ?69 (original text source-text extraction is disordered, requires confirmation against the source standard (source-text extraction))
  • Intake air humidity, g/kg: 11.4±0.7
  • Exhaust back pressure, kPa (absolute): 103.5±0.7
  • Air-fuel ratio: 16.5±0.5
  • Ignition timing, °BTDC: 34±1

7. Sampling and Test Sample Preparation

• 13.3.1.4 Sampling, oil replenishment, and oil level adjustment: Before the end of each cycle, 15min, drain the dead zone oil 300mL from the drain valve, take a sample 80mL, and then add 400mL of new test oil to the engine. After stopping, turn off the oil pump. After 20min, check the oil level and adjust the oil level with the dead zone oil (see D.2 in Appendix D).
• 14.2.7 Oil sample analysis: Determine the kinematic viscosity at 40℃ of the test oil samples from each stage. Before sampling with the viscometer, the test oil sample should be shaken well (but the test oil sample must not be filtered or dehydrated) to ensure the accuracy of the measured data. Calculate the viscosity increase rate of the oil sample.
• Appendix D (Informative Appendix) CEPT-Ⅲ Operation Record Sheet:
  • D.1 Test operating condition record sheet.
  • D.2 Test oil collection, oil level check, and oil consumption measurement: Includes operations such as draining the 300mL "dead zone" oil sample, taking the 80mL analysis oil sample, adding 400mL new oil, pouring the 300mL "dead zone" oil sample back into the engine, stopping the engine, checking the oil level after stopping for 25min, replenishing the oil level to the "baseline" level with the 300mL oil sample, discarding the remaining oil sample, determining the final oil level, and calculating oil consumption.
  • D.3 Blowby measurement sheet: Includes columns such as test time, speed, load, orifice diameter, pressure difference (ΔP), temperature, atmospheric pressure, uncorrected blowby flow rate, correction factor, and corrected blowby flow rate.

8. Analysis Procedure

• 11 Preparation of test apparatus:
  • 11.1 Engine preparation: For each test, the following new parts must be used: camshaft, rocker arms, pistons, piston pins, piston rings, connecting rod bearings, main bearings, intake valves, exhaust valves, spark plugs, various seals and gaskets. Other components may be reused after inspection and qualification.
    • 11.1.1 Measurement of engine parts: Before engine assembly, measure some components (for the components to be measured and measurement items, see Appendix C).
    • 11.1.2 Oil pan, rocker cover, rocker cover inner baffle: Soak and clean the oil pan, rocker cover, and rocker cover inner baffle with solvent oil, then blow dry with compressed air.
    • 11.1.3 Rocker arms: The rocker arms shall be soaked and cleaned with solvent oil, and after cleaning, blown dry with compressed air. Then weigh with an analytical balance and record.
    • 11.1.4 Camshaft: Clean the camshaft with solvent oil and blow dry with compressed air. Measure and record the height of each cam from the base circle to the top. After measurement, coat the cams with test oil to prevent rust.
    • 11.1.5 Crankshaft: Measure and record the diameter dimensions of each journal. The roundness of the journals shall not be greater than 0.015mm.
    • 11.1.6 Cylinder head: Wash clean and blow dry with compressed air, check whether each oil passage and cooling passage is unobstructed. The cylinder head may be used at most twice.
      • 11.1.6.1 Valve guide: Measure and record the clearance between the valve stem and guide for each valve. Exhaust: 0.076mm–0.119mm; Intake: 0.022mm–0.065mm.
      • 11.1.6.2 Camshaft bearing support: Ensure that the bearing bore and camshaft journal have suitable clearance (must not be less than 0.7mm).
    • 11.1.7 Cylinder block: Before measuring and honing, the cylinder gasket and pressure plate must be installed, and the screws tightened according to the specified torque requirements (see 11.2.5). For a reused cylinder block, hone the inner surface to form a cross-hatch pattern of 30°–40°, with a surface roughness of 0.20μm–0.36μm. When measuring the cylinder inner diameter, first wipe clean with a dry soft cloth, then use an inner diameter micrometer to measure each cylinder at the upper, middle, and lower positions in both parallel and perpendicular dimensions. The roundness of the cylinder inner diameter is the difference between the parallel and perpendicular diameters; the roundness at the upper, middle, and lower positions must not exceed 0.012mm. The cylindricity is the difference between the maximum and minimum of that cylinder; the maximum cylindricity at any position shall not exceed 0.025mm. If any of the above items is out of tolerance, re-honing shall be performed. The cylinder inner diameter dimension is determined by the corresponding piston skirt diameter plus the clearance of 0.030mm~0.070mm. The required clearance can be ensured by honing the cylinder or selecting and matching pistons.
    • 11.1.8 Piston: Pistons with peeling tin plating and discoloration on the skirt surface cannot be used. Measure and record the piston skirt diameter perpendicular to the piston pin centerline; this diameter can be used to determine the clearance between the piston and the cylinder inner diameter.
    • 11.1.9 Piston rings: The piston rings and piston must be matched. The end gap of the two compression rings must reach 0.71mm–0.76mm to obtain the specified crankcase blowby. When measuring the end gap, push the piston ring to a specific position using the piston measuring locator. After measurement, install the four sets of piston rings onto the corresponding pistons and measure the side clearance of the compression rings. The top ring side clearance is 0.038mm–0.078mm, and the second ring side clearance is 0.038mm~0.093mm.
    • 11.1.10 Piston pin: Heat the small end of the connecting rod with a heater, then insert the piston pin into the piston and connecting rod so that it is fixed on the connecting rod.
    • 11.1.11 Connecting rod: The diameter of the connecting rod oil hole should be 2.30mm~2.40mm. When installing the piston onto the connecting rod, the front part of the piston (usually marked with F) and the connecting rod oil hole should face the same direction.
    • 11.1.12 Main bearings and connecting rod bearings: Measure their clearances. The clearance between the main bearings and the crankshaft is: 0.007mm–0.080mm; the clearance between the connecting rod bearings and the connecting rod journals is: 0.019mm–0.087mm. Mark the bearings, wash clean and blow dry with compressed air, then weigh and record.
    • 11.1.13 Intake manifold: Install the intake manifold pressure sensor on the manifold between cylinders 3 and 4. Before each test, soak and thoroughly clean the intake manifold with carburetor cleaner.
  • 11.2 Engine assembly: Strictly follow the requirements in the CA488 engine assembly instruction manual.
    • 11.2.1 Crankshaft installation: The tightening torque for the main bearing cap nuts is 95N·m.
    • 11.2.2 Connecting rod installation: Install according to the sequence numbers on the connecting rods. The tightening torque for the connecting rod bearing cap nuts is 80N·m.
    • 11.2.3 Distributor drive installation: Install the modified distributor drive.
    • 11.2.4 Oil pan installation: After applying silicone rubber flat sealant to the mating surface between the oil pan and the cylinder block, install the oil pan. The bolt tightening torque is 23N·m.
    • 11.2.5 Cylinder head installation: Install the cylinder head onto the cylinder block and tighten in three stages: first stage 80N·m, second stage 95N·m, third stage 110N·m.
    • 11.2.6 Rocker arm cover and rocker arm cover inner baffle installation: The cam baffle is fixed to the rocker shaft support with special studs and nuts; the baffle must not touch the inner surface of the rocker arm cover or the rocker arms. The rocker arm cover bolt tightening torque is 12N·m.
    • 11.2.7 Ignition timing parts installation: Install the components according to the relative positions of the crankshaft, intermediate shaft, and camshaft. Avoid reverse rotation of the crankshaft during installation.
    • 11.2.8 Exhaust system installation: All bolts and nuts of the exhaust system should be coated with high-temperature anti-seize thread lubricant, and the nuts tightened according to torque 23N·m. Check the exhaust sampling pipe for blockage, cracks, and deformation.
    • 11.2.9 Intake system installation: Tighten the nuts according to torque 23N·m. Check the fuel line connected to the carburetor for leaks.
    • 11.2.10 Engine cooling system installation: Connect the inlet and outlet lines.
    • 11.2.11 Rocker arm cover and blowby condenser cooling system installation: Connect the inlet and outlet lines.
    • 11.2.12 External lubrication system installation: Install the adapter at the original engine oil filter location and connect the hose. Install a 75μm fine filter screen in the oil filter for use during the test run.
    • 11.2.13 Oil filler pipe installation: Install the oil filler pipe.
    • 11.2.14 Ignition system installation: Install new spark plugs, the electrode gap should be 0.7mm~0.9mm, and the tightening torque is 25N·m. Install the distributor and high-voltage wires according to the cylinder ignition order 1-3-4-2. Turn the crankshaft to near the top dead center of the compression stroke of cylinder 1, and initially adjust the distributor rotor position.
    • 11.2.15 Other installations: Connect thermocouples and pressure measurement lines. Check whether all connecting lines are secure and correct.
• 12 Test bench calibration:
  • 12.1 Reference oil test: After the test bench has undergone 15 formal tests, a calibration test should be performed using reference oil.
  • 12.2 Instrument calibration:
    • 12.2.1 Engine load calibration: Engine load readings use torque (N·m). The load measurement and display system must be calibrated with special weights, at least once per test.
    • 12.2.2 Coolant flow calibration: The flow meters of the two cooling systems should be calibrated on the test bench. Calibrate using turbine flow meters or by measuring the volume flowing per unit time.
    • 12.2.3 Fuel flow calibration: Mass flow and calibrated at least once every 3 tests. Volumetric flow meters should have temperature compensation and be calibrated against a mass flow meter. The flow meter installed on the test bench should be accurate to within 1% of the calibration reading.
    • 12.2.4 Exhaust analyzer calibration: Before each measurement, it must be calibrated with standard gases. The standard gases are: nitrogen containing 6.5% carbon monoxide; nitrogen with carbon monoxide (original text source-text extraction incomplete, requires confirmation against the source standard (source-text extraction)); nitrogen containing 50% oxygen; nitrogen containing 0.5% oxygen.
    • 12.2.5 Thermocouple calibration: Each thermocouple should be calibrated before each test.
    • 12.2.6 Calibration of other equipment: The cylinder inner surface roughness measuring instrument, spring testing machine, and crankcase blowby measuring instrument should all be periodically calibrated according to usage requirements.
• 13 Test:
  • 13.1 Pre-test preparation:
    • 13.1.1 Calibration of instruments and meters: If problems are found with instruments during the test or during testing, they should be calibrated and adjusted promptly; calibration regulations are in Chapter 12.
    • 13.1.2 Cleaning of external oil system: Before each test, the external oil system must be thoroughly cleaned. Use No. 190 solvent oil to clean the oil filter, oil heater, and oil cooler to remove residual sludge and debris from the previous test; after cleaning, blow dry with compressed air.
    • 13.1.3 Cleaning of cooling system: If deposits are found in the two cooling systems, clean with cleaning agent. First, circulate a solution of 20L water plus 500g sodium sulfate with the pump running for 0.5h, then circulate a solution of 40L water plus 500g trisodium phosphate with the pump running for 0.5h, and finally rinse repeatedly with softened water until clean.
    • 13.1.4 Cleaning of crankcase blowby condenser and oil-water separator: Soak and clean with No. 190 solvent oil, then blow dry with compressed air.
    • 13.1.5 Cleaning of carburetor: Before the test, clean the carburetor fuel and intake passages with carburetor cleaner, then blow dry with compressed air. If the air-fuel ratio is difficult to adjust during the test, timely cleaning should also be considered.
    • 13.1.6 Inspection of dynamometer and drive shaft: Perform according to the device instruction manual. Add lubricating oil or grease promptly.
    • 13.1.7 Other checks: Check all lines and thermocouples. If damage is found, repair and replace promptly. After the above checks are correct, add ethylene glycol coolant containing additives to the two cooling tanks, start the cooling pump to remove air from the lines; add 4L test oil at the oil filler port, turn on the oil pump and adjust the oil pressure to 450kPa±25kPa. Check for leaks, turn on all power, water valves, air valves, fuel valves, open the intake adjustment device and refrigerator, check whether the dynamometer water pressure meets requirements and whether the fuel pressure before the carburetor reaches 30kPa±10kPa.
  • 13.2 Trial run: Perform the trial run according to the conditions in Table 1. During the trial run, adjust the ignition timing to 34° before top dead center. Adjust the oil pressure to 375kPa±25kPa. After the trial run, turn off the oil pump, replace the 75μm fine filter screen with the 115μm coarse filter screen. Then start the oil pump to expel air from the system, then turn off the oil pump, stop for 20min, check the oil level, and then proceed with the formal test.
  • 13.3 Formal test: Start the engine; when the oil temperature reaches 148℃±1℃, begin timing. The formal test totals 64h, including 8 cycles, each cycle being 8h. The formal test conditions are in Table 2.
    • 13.3.1 Work during the test:
      • 13.3.1.1 Parameter monitoring: All operating conditions should be controlled within the ranges specified in Table 2, and data recorded once per hour (see Appendix D).
      • 13.3.1.2 Measurement of crankcase blowby: Measure and record the crankcase blowby each cycle. During measurement, the engine must be under stable test conditions.
      • 13.3.1.3 Exhaust analysis: Measure the carbon monoxide, carbon dioxide, and oxygen content in the exhaust once every 24h to ensure the air-fuel ratio is within the range of 16.5±0.5 (see Appendix G).
      • 13.3.1.4 Sampling, oil replenishment, and oil level adjustment: Before the end of each cycle 15min, drain dead zone oil 300mL from the drain valve, take a sample 80mL, then add 400mL new test oil to the engine. After stopping, turn off the oil pump. After 20min, check the oil level and adjust the oil level with dead zone oil (see D.2 in Appendix D).
    • 13.3.2 End of test: After stopping, drain the test oil, drain the coolant from the two cooling systems, and disassemble the engine as soon as possible.

9. Qualitative and quantitative and calculation formulas

• 14 Evaluation and reporting of test results:
  • 14.1 Preparation before scoring: The sludge scoring parts and the oil filter screen must be placed vertically for more than 8h so that residual oil on them can drain off. The specific placement positions are as follows: the front part of the rocker cover faces downward; the rear part of the baffle inside the rocker cover faces downward; the side of the cylinder head with intake and exhaust ports faces downward; the front and rear crankshaft seal covers are placed according to their installation orientation in the engine; the upper edge of the oil pan faces downward; the engine cylinder block is placed in its normal position.
  • 14.2 Evaluation of test results: Carry out according to the provisions of SH/T 0510, using the scoring table in Appendix E.
    • 14.2.1 Sludge scoring: The engine sludge score is the arithmetic mean of the sludge scores of 7 parts: the rocker cover, the baffle inside the rocker cover, the upper surface of the cylinder head, the front crankshaft seal cover, the rear crankshaft seal cover, the lower surface of the cylinder block, and the oil pan surface.
    • 14.2.2 Varnish scoring:
      • 14.2.2.1 Piston skirt varnish scoring: The piston skirt varnish score is the arithmetic mean of the piston skirt varnish scores of 4 pistons.
      • 14.2.2.2 Oil ring land varnish scoring: The arithmetic mean of the varnish scores of the oil ring lands of 4 pistons (the upper ring land of the oil ring land accounts for 55%, and the lower ring land accounts for 45%).
    • 14.2.3 Blockage:
      • 14.2.3.1 Blockage of the oil pump filter screen: Evaluate the percentage of the filter screen blockage area blocked by sludge and residue. Distinguish whether the blocking material is sludge or residue, and state it in the report.
      • 14.2.3.2 Blockage of the oil rings: Evaluate the percentage of the oil ring blockage area of the four pistons, and calculate the average blockage rate.
    • 14.2.4 Wear:
      • 14.2.4.1 Cam wear: Measure and calculate the height difference of the cam before and after the test. Calculate the average wear of 8 cams and list the maximum wear. Use formula (1) and formula (2) to correct the average cam wear and maximum cam wear.
        • Formula (1): Y = 6.0391X + 0.0199
          • Where: Y—— corrected average cam wear value, mm; X—— measured average cam wear value, mm.
        • Formula (2): Y = 6.8358X + 0.0023
          • Where: Y—— corrected maximum cam wear value, mm; X—— measured maximum cam wear value, mm.
      • 14.2.4.2 Bearing shell wear (weight loss): The difference in mass of the bearing shell before and after the test is the weight loss