ASTM D6891 Standard Test Method for Evaluation of Automotive Engine Oils in the Sequence IVA Spark-Ignition Engine
11. Procedure
NOTE 11 - When installing a new engine and cylinder head or both, conduct a break-in procedure, see 11.1.3, before running official 100 h tests. After completing the break-in, install the official test valve-train parts as shown in 9.7. Then conduct a double oil-flush procedure as shown in 11.2.2. After performing the double oil-flush, conduct the 100 h test as shown in 11.2.3. Use Annex A5 for operational conditions.

11.1 Pre-test Procedure:
11.1.1 Engine Coolant System Flushing - When replacing the engine short-block (normally every 20 tests), clean the coolant system (including heat exchanger) before conducting the engine break-in. By using an external electric-driven coolant-circulating pump, the installed engine does not have to be running during the flush-cleaning process. Exclude sensitive components of the coolant flow meter from the flushing chemicals. Check the calibration of the coolant flow meter after flushing the coolant system.
11.1.1.1 Circulate the cooling system cleanser for 30 min at a target temperature of 50 °C using the electric heating element for the coolant system.

11.1.1.2 Following the 30 min cleaning process, turn off the electric heater for the coolant system. Open the coolant system drain valves, add fresh water until the drains are clear, and the pH of the incoming and outgoing fresh water is unchanged. Fully drain the system.

11.1.1.3 Fill coolant system with a pre-mixed coolant consisting of 50:50 volume percent mixture of the specified extended-life ethylene-glycol anti-freeze and deionized, demineralized, or distilled water. Operate the coolant pump to bleed air from the coolant system. Use this coolant charge for eight tests, or until replacing the engine or cylinder head.

11.1.2 Engine Pre-lubrication - The oil pump drive is directly connected to the engine crankshaft, which makes it impractical to pressure lubricate the engine prior to start-up. Build oil pressure quickly by pre-filling the oil filter with 325 mL of the appropriate lubricant. Bleed air from the rocker arm lash adjusters before installing these components in the engine. Immerse the rocker arms in a container of SAE 20 API SA grade oil while laying on their side. After soaking, keep the rocker arms straight up until installing to prevent air from entering the lash adjusters.

11.1.3 Engine Break-in Procedure - Conduct the break-in procedure prior to lubricant evaluation testing when installing a new engine short-block, new long-block, or new cylinder head on the test stand. The break-in allows for setting the ignition timing, purging air from the coolant system, checking for leaks in the various systems, and monitoring engine performance and test stand instrumentation. Follow the prescribed break-in conditions in Table A6.1. Use the engine short-block assembly for 20 tests and the cylinder head assembly for 10 tests. Perform new engine break-in once every 10 tests. Use the following break-in steps:
11.1.3.1 Install the new test engine assembly with break-in test parts (camshaft, rocker arms, rocker shafts that come with pre-assembled cylinder head) onto the test stand.

11.1.3.2 Open the oil drain valve in the oil pan and pre-fill the cavities of the cylinder head under the camshaft with break-in oil REO 926-2. Close the oil drain valve once completed.

11.1.3.3 Install the rocker cover.

11.1.3.4 Charge the coolant system with a 50:50 mixture of deionized water and extended life coolant. The coolant system capacity is 25 L.

11.1.3.5 Connect the stand to a fuel tank containing the test fuel.

11.1.3.6 Measure by volume, 3.5 L of break-in oil REO 926-2.

11.1.3.7 Install a new oil filter onto the engine. Perform the following steps to help the oil pressure build quicker during initial start-up. Do not install a dry oil filter on a test engine.
(1) Obtain a new break-in oil filter and remove it from its packaging.
(2) Measure out 325 mL of oil from the new break-in oil charge.
(3) Holding the oil filter upright; pre-fill the filter with the 325 mL of new break-in oil.
(4) Tilt the filter and slowly rotate it a full 360° several times to let the oil absorb into the entire fiber filter element.
(5) Install the filter onto the engine. By letting the oil absorb into the entire filter element, no oil should spill out when tilting the filter to install it.

11.1.3.8 Fill the engine with the remainder of the 3.5 L break-in oil charge.

11.1.3.9 Circulate and preheat the engine coolant to 50 °C and then warm soak the engine for 10 min before initial start-up.

11.1.3.10 Start the engine and crack the throttle open 5 % to 10 % to raise the engine speed, not to exceed 1500 r/min, to help the oil pressure build quicker. Once oil pressure has started to build control engine speed to 800 r/min, control torque to 10 N·m and ramp oil temperature to 50 °C.

11.1.3.11 Once the engine achieves 800 r/min, use a timing light to set the ignition timing to 10° Before Top Dead Center (BTDC).

11.1.3.12 Start the break-in sequence and run through all 8 steps. Total running time is 95 min.

11.1.3.13 After completing the compression check, drain the engine oil for 30 min and remove the used oil filter.

11.1.3.14 Remove the rocker cover.

11.1.3.15 Using a suction device, remove the used break-in oil that is trapped in the cylinder head cavities under the camshaft.

11.1.3.16 Examine the used engine oil for unusual amounts of metal particles.

11.1.3.17 Remove the break-in test parts (camshaft, rocker arms, rocker shafts).

11.1.3.18 After completing break-in, check the engine assembly for anything unusual.

11.1.3.19 If acceptable, the engine is ready for test work.

11.2 Engine Operating Procedure - The Valve-train Wear test is a double-flush and run test. Conduct the oil flush and test operations as shown in 11.2.2 - 11.2.3, and in Annex A5.
11.2.1 Preparation of Test:
11.2.1.1 Remove a 237 mL sample of new test oil for chemical analyses of the 0 h test oil. Use a 237 mL plastic container.

11.2.1.2 Install the test parts (camshaft, rocker arms, rocker shafts) according to procedure.

11.2.1.3 Open the oil drain valve in the oil pan and pre-fill the cavities of the cylinder head under the camshaft with new test oil. Close the oil drain valve once completed.

11.2.1.4 Reinstall the rocker cover. Inspect and replace rocker cover gasket if necessary.

11.2.1.5 Connect the stand to a fuel tank containing the test fuel.

11.2.2 Double Oil Flush:
11.2.2.1 Measure by volume 3.5 L of new test oil.

11.2.2.2 Install a new oil filter onto the engine (see Annex A6). Perform the following steps to help the oil pressure build quicker during initial start-up. Do not install a dry oil filter on the test engine.
(1) Obtain a new flush oil filter and remove it from its packaging.
(2) Measure out 325 mL of oil from the new flush oil charge.
(3) Holding the oil filter upright, pre-fill the filter with the 325 mL of new flush oil.
(4) Tilt the filter and slowly rotate it a full 360° several times to let the oil absorb into the entire fiber filter element.
(5) Install the filter onto the engine. By letting the oil absorb into the entire filter element, no oil should spill out when tilting the filter to install it.

11.2.2.3 Fill the engine with the remainder of the 3.5 L flush oil charge.

11.2.2.4 Circulate and preheat the engine coolant to 50 °C and then warm soak the engine for 10 min before initial start-up.

11.2.2.5 Start the engine and crack the throttle opened 5 % to 10 % to raise the engine speed, not to exceed 1500 r/min, to help the oil pressure build quicker. During engine start-up, target 1200 r/min. Once oil pressure has started to build and within 30 s of engine start, control engine speed to 800 r/min, control torque to 10 N·m and ramp oil temperature to 50 °C.

11.2.2.6 Once the oil temperature has reached 50 °C run Flush 1 according to the prescribed flush conditions Table A5.2. Flush 1 is a 20 min flush operating the engine at 800 r/min and 10 N·m of torque.

11.2.2.7 Check ignition timing with timing light during Flush 1 to verify it is set at 10° BTDC. Correct if not set at 10° BTDC.

11.2.2.8 Shut down the engine at the end of the 20 min flush. Proceed to drain the engine oil and remove the used oil filter. Drain used oil for 30 min. Maintain coolant flow at 30 L/min and coolant temperature at 50 °C during the oil drain period.

11.2.2.9 After draining the Flush 1 oil, measure by volume, 3.5 L of new test oil.

11.2.2.10 Install a new oil filter onto the engine (see Annex A6). Perform the following steps to help the oil pressure build quicker during initial start-up. Do not install a dry oil filter on the test engine.
(1) Obtain a new flush oil filter and remove it from its packaging.
(2) Measure out 325 mL of oil from the new flush oil charge.
(3) Holding the oil filter upright, pre-fill the filter with the 325 mL of new flush oil.
(4) Tilt the filter and slowly rotate it a full 360° several times to let the oil absorb into the entire fiber filter element.
(5) Install the filter onto the engine. By letting the oil absorb into the entire filter element no oil should spill out when tilting the filter.

11.2.2.11 Fill the engine with the remainder of the 3.5 L flush oil charge. If the engine coolant pump was shut off during the oil drain period (for maintenance or diagnostic work) circulate and preheat the engine coolant to 50 °C and then warm soak the engine for 10 min before initial start-up.

11.2.2.12 Start the engine and crack the throttle opened 5 % to 10 %, to raise the engine speed, not to exceed 1500 r/min, to help the oil pressure build quicker. Once oil pressure has started to build within 30 s of engine start, control engine speed to 1500 r/min, control torque to 10 N·m and ramp oil temperature to 60 °C.

11.2.2.13 Once the oil temperature has reached 60 °C run Flush 2 according to the prescribed flush conditions (Annex A5). Flush 2 is a 20 min flush operating the engine at 1500 r/min and 10 N·m of torque.

11.2.2.14 Shut down the engine at the end of the 20 min flush. If a problem is suspected with the test engine, perform a compression check on all four cylinders before draining the engine oil; otherwise no compression check is required. Record the data on the sheet provided. If the compression on any cylinder is below 900 kPa or is lower than 20 % from the median value for that engine, investigate the cause before proceeding with a test.

11.2.2.15 Drain the engine oil and remove the used oil filter. Drain the used oil for 30 min.

11.2.3 Test:
11.2.3.1 Once both 20 min flushes and the 30 min oil drain have been completed, obtain the tare mass of a container to measure the test oil charge.

11.2.3.2 Measure by volume, 3.00 L of new test oil.

11.2.3.3 Weigh and record the mass of the 3.00 L oil sample before charging the engine.

11.2.3.4 Obtain a new test oil filter (see Annex A6), weigh it dry, and record for use in calculating oil consumption in 11.5.1.

11.2.3.5 Install the weighed, new oil filter onto the engine. Perform the following steps to help the oil pressure build quicker during initial start-up. Do not install a dry oil filter on the test engine.
(1) Measure out 325 mL of oil from the new test oil charge.
(2) Holding the oil filter upright, pre-fill the filter with the 325 mL of new test oil.
(3) Tilt the filter and slowly rotate it a full 360° several times to let the oil absorb into the entire fiber filter element.
(4) Install the filter onto the engine. By letting the oil absorb into the entire filter element, no oil should spill out when tilting the filter for installation.

11.2.3.6 Fill the engine with the remainder of the 3.00 L test oil charge.

11.2.3.7 If the coolant pump was shut down during the oil drain period following the double flush procedure (for maintenance or stand repair), circulate and preheat the engine coolant to 50 °C and then warm soak the engine for 10 min before initial start-up. If coolant flow was maintained during the oil drain period, the coolant preheat and soak period may be omitted.

11.2.3.8 Start the engine and crack the throttle open 5 % to 10 %, not to exceed 1500 r/min, to raise the engine speed and to help the oil pressure build quicker. Once oil pressure has started to build, and within 30 s of engine start, control engine speed to 800 r/min and control torque to 25 N·m and ramp oil temperature to 50 °C.

11.2.3.9 Once the oil temperature has reached 50 °C, initiate the 100 h test. Follow the prescribed test conditions (Annex A5).

11.2.3.10 While running the engine, check for any coolant or oil leaks. The engine will run for the entire 100 cycles (100 h) without any scheduled shutdowns, but unscheduled shutdowns for repair may occur.

11.2.3.11 Drain condensation traps once every 8 h.

11.2.4 Unscheduled Engine Shutdown Procedure - Follow the procedure detailed in 11.2.4.1 and 11.2.4.2 when performing an unscheduled engine shutdown. Document the shutdown duration, shutdown reason, and the action taken. Document this information on the appropriate report form. The test time requirement does not include any shutdown time.
11.2.4.1 Emergency Shutdown - An emergency shutdown usually precludes an organized shutdown. Prevent the test lubricant from overheating and prevent excessive fuel dilution. Avoid excessive engine cranking, if it will not start. Excessive cranking may affect camshaft lobe wear.

11.2.4.2 Restart After Unscheduled Shutdown - Preheat the coolant to 50 °C. Start the engine and crack the throttle open 5 % to 10 % to raise the engine speed, not to exceed 1500 r/min, to help the oil pressure build quicker. During engine start-up, target to 1200 r/min. Once oil pressure has started to build and within 30 s of engine start, bring speed up to 1500 r/min and apply 25 N·m torque. Stabilize for 5 min. Then use 5 min ramp to intended stage of test. This ensures each start-up will take 10 min before the test is resumed.

11.2.5 Cyclic Schedule, General Description - See Annex A5 for the steady-state operating test conditions (specification targets). The actual test operational conditions are summarized on the appropriate report form.

11.2.6 Transient Ramping of Parameters - Engine speed ramping, temperatures, and torque fluctuations between stages influence wear severity. Therefore, the importance of ramping rates. Record a plot of cycle 5 transitions on the appropriate report form.
11.2.6.1 Oil Temperature Transitions:
(1) After Stage I, increase the cylinder head oil gallery temperature from a nominal 49 °C to the Stage II oil gallery temperature target of 59 °C. The transitory time is defined as the first 5 min of Stage II, following the end of Stage I. At 1 min into the ramp, the cylinder head oil gallery temperature shall range from 51 °C to 53 °C. At 2 min into the ramp, the cylinder head oil gallery temperature shall range from (54 to 56) °C. At 3 min into the ramp, the cylinder head oil gallery temperature shall be at or above 57 °C. By the end of the 5 min ramp, stabilize the cylinder head oil gallery temperatures at 59 °C +/- 0.5 °C.
(2) After Stage II, decrease the cylinder head oil gallery temperature from a nominal 59 °C to the Stage I cylinder head oil gallery temperature target of 49 °C. The transitory time is defined as the first 5 min of Stage I, following the end of Stage II. At 1 min into the ramp, the cylinder head oil gallery temperature shall range from 55 °C to 57 °C. At 2 min into the ramp, the cylinder head oil gallery temperature shall range from 52 °C to 54 °C. At 3 min into the ramp, the cylinder head oil gallery temperature shall be at or below 51 °C. By the end of the 5 min ramp, stabilize the cylinder head oil gallery temperature at 49 °C +/- 0.5 °C.

11.2.6.2 Coolant Temperature Transitions:
(1) After Stage I, increase the coolant out temperature from a nominal 50 °C to the Stage II coolant out temperature target of 55 °C. The transitory time is defined as the first 5 min of Stage II, following the end of Stage I. At 1 min into the ramp, the coolant out temperature shall range from 51 °C to 52 °C. At 3 min into the ramp, the coolant out temperature shall be at or above 54 °C with minimal overshoot. By the end of the 5 min ramp, stabilize the coolant out temperature at 55 °C +/- 0.5 °C.
(2) After Stage II, decrease the coolant out temperature from a nominal 55 °C to the Stage I coolant out temperature target of 50 °C. The transitory time is defined as the first 5 min of Stage I, following the end of Stage II. At 1 min into the ramp, the coolant out temperature shall range from 53 °C to 54 °C. At 3 min into the ramp, the coolant out temperature shall be at or below 51 °C with minimal undershoot. By the end of the 5 min ramp, stabilize the coolant out temperature at 50 °C +/- 0.5 °C.

11.2.6.3 Engine Speed Transitions:
(1) After Stage I, increase the engine speed with minimal overshoot from a nominal 800 r/min to the Stage II engine speed target of 1500 r/min. Do not allow speed to exceed 1600 r/min during the transition. The transitory time is defined as the first 5 min of Stage II, following the end of Stage I. At 30 s into the ramp, the engine speed shall range from 1100 r/min to 1200 r/min. At 60 s into the ramp, the engine speed shall range from 1400 r/min to 1500 r/min. By the end of the 5 min ramp, stabilize the engine speed at 1500 r/min +/- 20 r/min.
(2) After Stage II, decrease the engine speed with minimal undershoot from a nominal 1500 r/min to the Stage I engine speed target of 800 r/min. Do not allow speed to drop below 750 r/min during the transition. The transitory time is defined as the first 5 min of Stage I, following the end of Stage II. At 30 s into the ramp, the engine speed shall range from 1100 r/min to 120 r/min. At 60 s into the ramp, the engine speed shall range from 800 r/min to 900 r/min. By the end of the 5 min ramp, stabilize the engine speed at 800 r/min +/- 20 r/min.

11.2.6.4 Torque Steadiness During Transitions - If using a transfer program for speed and torque control, the torque can be changed to help stabilize control during the transfer and ramp for Stage I to Stage II, and Stage II to Stage I. During the 5 min transitions for speed and temperature changes, control the torque within 23 N·m to 27 N·m. By the end of the 5 min ramp, stabilize the torque at 25 N·m +/- 1.5 N·m.

11.3 Periodic Measurements and Functions:
11.3.1 Blowby Flow Rate Measurement - Measure and record the blowby flow rate during the middle of Stage I of cycle 5 and cycle 100. Stabilize and operate the engine at normal Stage I operating conditions. Use a 3.175 mm diameter blowby orifice size for the normal blowby flow range of 5 L/min to 12 L/min. An apparatus similar to those shown in schematics in Fig.A7.17 and Fig.A7.18 may be used. The design of the apparatus is left up to the discretion of the laboratory. Perform steps 11.3.1.1 through 11.3.1.8 when using a device similar to the schematic in Fig.A7.17 or perform steps 11.3.1.9 through 11.3.1.15 when using a device similar to the schematic in Fig.A7.18.
11.3.1.1 Open the flow valve (bleeder valve) completely.

11.3.1.2 Connect the blowby apparatus flow line to the 3-way valve located between the engine PCV and intake vacuum port.

11.3.1.3 Disconnect the hose at the air cleaner that is routed from the rocker cover. Then connect it to the inlet plumbing of the blowby apparatus orifice meter.

11.3.1.4 Position the 3-way valve to divert intake manifold vacuum from the engine PVC to the exhaust plumbing of the blowby apparatus meter.

11.3.1.5 Connect the blowby apparatus pressure sensor to the dipstick tube.

11.3.1.6 Adjust the flow valve (bleeder valve) to maintain crankcase pressure at 0 kPa to 0.025 kPa.

11.3.1.7 Record the differential pressure across the blowby meter orifice, record the blowby gas temperature, and the barometric pressure.

11.3.1.8 After completing the measurement, return the engine to normal operating configuration. First, the dipstick tube pressure port; second, reconnect the hose from the rocker cover to the air cleaner; third, reposition the 3-way valve to ensure porting of the intake vacuum to the engine PCV; fourth, disconnect blowby apparatus hose from the closed port of the 3-way valve.

11.3.1.9 Connect the pressure gauge from the blowby measurement device to the dipstick tube. Where the pressure gauge is part of the measurement apparatus, plug the dipstick tube. It may also be necessary to isolate flow to the front cover.

11.3.1.10 Connect the blowby measurement device to the engine at the rocker cover.

11.3.1.11 Connect the blowby measurement device to the pressurized air source.

11.3.1.12 Slowly close the 3-way valve and the 3.2 mm needle-valve simultaneously.

11.3.1.13 Adjust the fine and coarse adjustment valves to maintain crankcase pressure at 0 kPa to 0.025 kPa, as measured by the gauge connected to the dipstick tube or on the measurement device.

11.3.1.14 Record the differential pressure across the blowby meter orifice, and record the blowby gas temperature and the barometric pressure. Ifthe pressure drop across the orifice goes below the levels on the manometer, use a 4.763 mm orifice, and repeat the measurement.

11.3.1.15 After completing the measurement, return the engine to normal operating configuration. First, the dipstick tube pressure port; second disconnect the blowby apparatus from the rocker cover; third, reposition the 3-way valve; fourth, return the 3.2 mm needle-valve to the fully open position.

11.3.1.16 Calculate the blowby flow rate and correct the value to standard conditions (38 °C, 100.3 kPa) using the calibration data for that orifice.

11.3.2 Ignition Timing Measurement - Measure and record the ignition timing during Stage I every fifth cycle. The specification is 10° +/- 1° at Stage I. Adjust when needed. Check the timing during Stage II, a typical reading of 24° +/- 2° indicates proper advance as determined by the engine controller.

11.3.3 Air-to-Fuel Ratio Measurement - Monitor the air-to-fuel ratio continuously using the output of a wide-range exhaust gas oxygen sensor.

11.3.4 Oil Additions and Used Oil Sampling - During the 100 h test, do not add oil. New oil makeup is not allowed if oil leaks occur. Take a 10 mL oil sample of the new oil, used oil at 25 h, used oil at 50 h, and used oil at 75 h. Remove used oil samples from the oil drain valve, located in the oil pan sump, during the transient portion of Stage II (near end of cycle 25, 50, and 75). Remove a 120 mL purge sample from the engine prior to drawing the oil sample. Return this purge sample to the engine by way of the cover fill cap using a clean filler pipe equipped with an isolation valve to prevent oil spit back due to positive crankcase pressure. After the oil consumption has been calculated at the end of 100 h, remove a 100 mLsample of used oil for chemical analyses of the 100 h test oil. Take the 100 mL sample during the final engine oil drain at the end of the test (100 h). No purge sample is required for this final oil sample.

11.3.5 General Maintenance:
11.3.5.1 Spark Plug Replacement - Replace the spark plugs (see Annex A6) before conducting the oil flushing procedure in 9.7.2.

11.3.5.2 PCV Valve Replacement - Replace the PCV valve, when replacing the engine or cylinder head. The PCV valve can be obtained from any authorized Nissan dealership.

11.4 Diagnostic Data Review - This section outlines significant characteristics of specific engine operating parameters. The parameters may directly influence the test or indicate normalcy of other parameters.
11.4.1 Intake Manifold Pressure - Several factors affect intake manifold pressure, including barometric pressure, engine load, air-fuel ratio, ignition timing, and engine wear. Use intake manifold pressure to monitor the engine condition, although not a specifically controlled parameter.

11.4.2 Fuel Consumption Rate - The fuel consumption rate during any stage shall remain relatively constant throughout the test. Like intake manifold pressure, use fuel consumption rate as a diagnostics tool. Fuel consumption rate and intake manifold pressure relate to similar operating parameters.

NOTE 12 - High fuel consumption rate can promote excessive cylinder bore, camshaft, and rocker arm wear.

11.4.3 Spark Knock - Spark knock does not normally occur during this test. The fuel octane rating, ignition timing, engine speed and load, and operating temperatures do not promote spark knock. Spark knock indicates abnormal combustion, and may cause extensive engine damage. If spark knock occurs, take immediate corrective action. Errors in the measurement and control of engine load, ignition timing, operating temperatures, and air-to-fuel ratio may result in spark knock.

11.4.4 Crankcase Pressure - Crankcase pressure is a function of blowby flow rate and PCV valve flow. High blowby flow rate or a significant loss of PCV valve flow causes high crankcase pressure. Incorrect 3-way valve plumbing or port plugging also promotes high crankcase pressure. High crankcase pressure may cause oil leaks (gasket or seal failure). Low blowby flow rate or a vent air restriction to the PCV valve may cause low or negative crankcase pressure.

11.4.5 Oil Pressure - The oil pressure is a function of oil viscosity, operating temperature, and engine bearing clearances. Normally, the oil pressure is higher in Stage II than Stage I. The oil pressure shall remain consistent throughout the test, unless the oil exhibits a significant increase in viscosity.
11.4.5.1 Abnormal Oil Pressures - An excessive oil pressure fluctuation may indicate large bearing clearance. An excessive oil pressure differential between the engine gallery and head gallery indicates the presence of a gallery restriction at the head gasket or an increased oil flow rate to the cam bearing pedestals.

11.4.6 Coolant Temperature Differential - The coolant temperature differential is a function of the coolant flow rate and is normally stable throughout the test. Coolant flow rate or temperature measurement errors may cause large variations in the differential. Foreign objects in or near the flow meter may cause coolant flow rate measurement errors.

11.5 End of Test Procedures - Shut down the engine at the end of cycle 100.
11.5.1 Oil Consumption Determination - Use the following equation to calculate oil consumption:
J = {(B - A) - [(F - E) + (H - D)]} = C - (G + I)
where:
C = B - A,
G = F - E, and
I = H - D.
where:
A = empty container mass, dry at test start, g,
B = initial oil charge and container mass, g,
C = initial oil charge, g,
D = new oil filter mass, dry at test start, g,
E = empty container mass, dry at test end, g,
F = drain oil and container mass e, g,
G = drain oil at end of test, g,
H = used oil filter mass, with absorbed oil, at end of test, g,
I = oil remaining in filter, g, and
J = oil consumption per test, g.

11.5.1.1 Oil Drain - Drain the engine test oil and remove the used test oil filter. While removing the oil filter, catch any oil that drains out. Add this oil to the drained test oil. Drain the used test oil for 30 min. Maintain a warm condition during the 30 min engine drain. Continue to circulate the coolant and maintain a 50 °C coolant temperature. Remove the rocker cover. Using a suction device, remove the used test oil that is trapped in the cavities of the cylinder head under the camshaft. Do not add this oil to the drained test oil. Properly discard this oil.

11.5.1.2 Measurement of Oil Drained - After completing the 30 min drain, and adding the oil from the oil filter, weigh the drained test oil and the used test oil filter. Use the equation provided in 11.5.1 to calculate oil consumption.

11.5.1.3 Used Oil Sample - After calculating the oil consumption, remove a 237 mL sample of used test oil for chemical analyses of the 100 h test oil. Use a 237 mL plastic container. After calculating oil consumption and obtaining the 237 mL sample for chemical analyses, place the remaining used test oil into a 4 L container and store.

11.5.2 Test Parts Removal - Remove the test parts (camshaft, rocker arms, rocker shafts) for wear measurement according to the procedures outlined in 9.7.1.

11.5.3 Lobe Wear Measurement:
11.5.3.1 After test, measure the camshaft lobes using a surface profilometer. From these graphical profile measurements, determine the maximum wear at seven locations on the cam lobe. Determine individual cam lobe wear by summing the seven location wear measurements. Average the wear from the twelve cam lobes for the final, primary test result.

11.5.3.2 Use a surface measurement profilometer with real time digital display and graphical output capability. Use a vertical scale graphical resolution capable of 1 µm per graph division. Use a profilometer capable of traversing at least 100 mm, with a straightness accuracy equal to or less than 1 µm per 100 mm of traversed length. Use a right angle pickup without a skid. Use a conical or spherical shaped diamond tip stylus, with a nominal radius of 2 µm to 5 µm. House the profilometer in an environment that meets the profilometer manufacturers recommendations. Maintain a clean area, temperature controlled, and stabilize and free the profilometer worktable from external vibration sources.

11.5.3.3 The Precision Devices Inc. MicroAnalyzer 2000 system is recommended as the computer-driven profilometer. Equip it with custom V-blocks (see Annex A6) for holding the work-piece (the camshaft on its journals). Use a diamond stylus that does not skid and that features a 0.005 mm stylus radius and a 6.5 mm stylus height. Take a trace across the lobe from front-to-rear of the lobe, at a traversing speed of 0.50 mm/s to 0.75 mm/s. Slightly extend (drop) the stylus off the lobe edges to ensure a full trace. View the data from the trace in the profile mode, allowing an analysis of the texture and waviness of the trace. Configure the instrument software for a two-point line texture leveling at the average value of the unworn edges of the cam lobe. Display the waviness of the profile using the Gaussian smoothing filter set at a cutoff length of 0.25 mm and with the filter set (nonstandard setting) to extend to the ends of the texture. Typically, the leveling line coincides with (contracts or is very close to) the highest peak of the waviness profile that exists at each unworn end. To obtain the wear measurement, the waviness evaluation length encompasses the whole lobe width. The Wt parameter (waviness total) yields the value of the height from the maximum peak to the lowest valley of the waviness profile. Record the wear measurement as the Wt measurement.

11.5.3.4 After the test, analyze the graphs of the profilometer traces of the cam lobe noses to determine the Wt. Since the cam lobe is wider than the rocker arm pad, there is a narrow non-worn edge at the rear of the cam lobe and another at the front of the cam lobe. If possible, discern these distinct non-worn edges, and draw the reference line on the graph. The nose wear is the maximum excursion (deepest valley) of the worn surface on the cam nose, as graphically measured normal to the reference line. In the absence of one of the discrete non-worn lobe edges, use the pre-test profile to extrapolate the reference line.

11.5.3.5 If two unworn edges are present, level the trace by the two-point method (electronic leveling).

11.5.3.6 If one of the unworn edges is missing, level the trace by the no form method (mechanical).

11.5.3.7 A cam lobe edge shall be at least 0.10 mm width and exhibiting an unworn surface finish pattern to be deemed an unworn edge. If the narrow edge is < 0.10 mm width, treat it as a worn edge and level the trace by the no form method.

11.5.3.8 If one unworn edge is missing, no anomalies exist, and at least 30 % of the trace exhibits no wear, level the trace by the two-point line method using the one large non-worn edge.

11.5.3.9 If an anomaly exists at the cam lobe unworn edge, either a significant rise or decline in slope, exclude the trace area from the wear calculation. Orient the waviness evaluation length lines as close as possible to the end of the trace while excluding the edge anomaly.

11.5.3.10 If a cam lobe defect exists such as surface scratches or an anomaly (pushed metal), orient the waviness evaluation length lines to exclude the defect or anomaly from the wear calculation.

11.5.3.11 When leveling by the no form method, mechanically level the camshaft on the ATC side of the cam lobe for the ATC traces and the BTC side of the cam lobe for the BTC traces. Run the ATC and BTC leveling traces at a point closest to TDC where two unworn edges are present, or where at least 30 % of the lobe exhibits no wear. Use the leveling trace closest to TDC for the TDC trace.

11.5.3.12 It will rarely occur that the above techniques provide a wear measurement that appears unreasonable (for example, a known unworn area that is not displayed as the highest point on a trace). When this occurs, consult the test engineer for the proper leveling and wear interpretation of that trace. Document the process utilized to make this wear measurement evaluation in the test report.