ASTM D6681 Standard Test Method for Evaluation of Engine Oils in a High Speed, Single-Cylinder Diesel Engine - Caterpillar 1P Test Procedure
11. Procedure
11.1 Engine Break-in Procedure - Open any drain taps at the low points of the combustion air system (if they are installed) during the start of the break-in and warm-ups, and following any shutdowns.
11.1.1 The engine break-in and operational conditions are specified in Annex A12. The total break-in time is 85 min. During the break-in, fix all leaks and make adjustments to ensure proper engine operation. Record the ECM personality module part number and release date.
11.1.2 After the break-in period and while the engine is hot, drain the oil from the crankcase, oil cooler, engine oil filter, and weigh scale for 30 min. Then weigh (5800 +/- 50) g of new test oil into the engine.
11.1.3 Start the engine, warm it up, and operate it for 360 h at the test conditions specified in step five of Annex A12 with no oil changes.
11.1.4 Turn on the oil scale pumps once the engine has reached the beginning of Step 5 of the warm-up sequence. Record the oil mass in the oil scale as the full mark at the end of the fourth test hour. Throughout the test, record the oil scale reading at least once every 6 min.
11.1.5 Count test time from the moment the warm-up time is completed. The oil sample frequency is described in Section 8.
11.1.6 Do not remove the cylinder head, piston, or power assembly from the engine during a test.
11.1.7 Reinitialize engine timing calibration after the cam shaft/gear or cylinder head has been removed. See the electronic installation and operation manual. Complete this during the first step of the break-in.
11.2 Cool-down Procedure - Except for emergency (uncontrolled) stops, shut the engine down by operating it at conditions shown in Steps 4, 3, 2, and then 1 in Annex A12.
11.3 Warm-up Procedure - Use the same procedure used for engine break-in to warm-up the engine for all subsequent starts throughout the test.
11.4 Shutdowns and Lost Time - Record the test hours, date, and length of off-test conditions for all occurrences. Record when the engine has early inspections or early test termination with the reasons for the occurrences. If the cool down procedure is not used, identify the shutdown as an Emergency Shutdown. A maximum allowed time of off-test conditions is 125 h. If the engine shuts down, immediately stop the oil scale pumps. In the event of an emergency shutdown, leave the engine shut down for 2 h (or more) to allow complete engine cool down before restarting. In order to limit foreign matter entering the combustion chamber and to protect piston deposits, rotate the engine to top dead center of the compression stroke during downtime.
11.5 Periodic Measurements - Record all engine conditions listed in Step 5 of Annex A12 as a snapshot at least once every 6 min. Record humidity readings using the laboratory's primary humidity measurement system. Correct the recorded humidity values to standard pressure conditions of 101.12 kPa. Record the fuel position as indicated by the electronic technician at test hours 24, 240, and 360.
11.6 Engine Control Systems:
11.6.1 Engine Coolant - Pressurize the coolant system to (35.0 +/- 7) kPa as shown in Annex A3 to ensure the water does not boil out of the antifreeze. Manually adjust the coolant flow rate by turning the valve on top of the coolant tower to maintain the conditions specified in Annex A12.
11.6.2 Engine Fuel System - Control the fuel rate by modifying the fuel limit adjusting the ECM using a facility controller that compares the actual fuel rate to the specified fuel rate listed in Annex A12. See the Electronic Installation and Operation manual for more details. Manually adjust the Fisher regulator to control fuel pressure. Maintain the fuel pressure and temperature as specified in Annex A12.
11.6.3 Engine Oil Temperature - Maintain the oil manifold temperature to test specifications as shown in Annex A12. The temperature of the Paratherm NF shall not exceed 165 °C at any time during break-in, warm-up, or testing. Shut off the external oil heater (but not its circulating pump) the moment the engine goes to cool-down.
11.6.4 Exhaust Pressure - Set the pressure as specified in Annex A12 using a facility feedback-controlled restrictor valve.
11.6.5 Intake Air - Filter, compress, and humidify the inlet air to the conditions specified in Annex A12. Heat (or cool, if necessary) the inlet air to the conditions in Annex A12.
11.7 Post-Test Procedures - Remove the piston and ring assembly from the engine. Mark the location of the ring gaps on top of the piston.
11.7.1 Piston Ring Side Clearances - Measure the piston ring side clearances prior to removal of the rings to determine the level of deposit formation (see Annex A10). Align ring gaps to the EOT ring gap marks on the top of the piston. Do not force the feeler gages between the ring and groove to disturb or remove the deposits.
11.7.2 Piston Ratings - Immerse the piston assembly in mineral spirits (see 7.14) and air-dry it prior to any rating.
11.7.2.1 Process and measure the piston deposits according to the Modified CRC Diesel Piston Rating Method described in ASTM Deposit Rating Manual 20 modified by the directions listed in Annex A13. Rate only two levels of carbon (heavy and light) on the second groove and all lands, and only one level of carbon (light) for the under-crown and cooling groove. Use a combined varnish rating method for the third groove, third land, fourth land, under-crown, and cooling groove (see Annex A13). An example rating worksheet is shown in Appendix X1.
11.7.2.2 Another heavy-duty engine deposit rater shall verify all piston deposit ratings done by the testing laboratory. In special cases where another rater is not available, the rating may be verified by other qualified laboratory personnel. Record the initials of both the rater and the verifying rater.
11.7.3 Referee Ratings - The referee laboratory rates the entire piston. Wrap all pistons to be referee-rated in paper with ASTM desiccant chips. Then place them in plastic and seal before shipping to the referee laboratory. Report referee ratings to the TMC within ten days of EOT for calibration tests. Referee-rate piston deposits for all non-reference tests reviewed by Caterpillar.
11.7.4 Ring EndGap Increase - Remove all carbon from the rings. If scraping of the rings is necessary, use only a wooden instrument or equivalent. Measure and record the ring end gaps.
11.7.5 Cylinder Liner Wear - Use a surface profile measurement to determine the liner wear step in both transverse and longitudinal directions relative to the crankshaft. Remove deposits on the liner above the piston ring travel. Take transverse and longitudinal measurements at the wear step location approximately 13 mm from the top of the liner at four locations. Record the measurements as the liner wear step.
11.7.6 Cylinder Liner Bore Polish - Section the cylinder liner through the front and rear axis and measure the cylinder liner to determine the amount of bore polishing. Use the liner rating method listed in Annex A13.
11.7.7 Photographs - Photograph the piston and rings showing the thrust, anti-thrust, front, rear, and undercrown positions (see Appendix X1). Place the rings on top of the piston to show ring gaps (thrust view) and 180° from gaps (anti-thrust view). Show the piston from the crown down to at least the bottom of the pin bore. Photograph the piston crown and skirt as one assembly. Photograph the bore ID of the sectioned liner (see Appendix X1).
