ASTM D6618 Standard Test Method for Evaluation of Engine Oils in Diesel Four-Stroke Cycle Supercharged 1M-PC Single Cylinder Oil Test Engine
9. Preparation of Apparatus
9.1 Supplementary Service Information:
9.1.1 Caterpillar Service Manual - Engine service information not found in this test method may be obtained by referring to the Caterpillar Single Cylinder Oil Test Engine Service Manual (Form No. SENR2074) and parts manual SEBP1299.

9.1.2 Pretest Maintenance Check List and Continuing Engine Inspection - Arecommended list of items that are checked or replaced at the intervals specified is shown in Table 5.

9.2 General Engine Inspection:
9.2.1 Perform a complete engine inspection every 10000 test hours. This inspection is done to ensure that wearing surfaces, such as main bearings and journals, rod bearings and journals, camshaft bearings, and so forth, are within manufacturer's specifications. This inspection will terminate the current test stand calibration (if any). Recalibration is required any time the crank is removed for any purpose other than bearing replacement.

9.2.2 Maintain a complete record of all engine maintenance and measurements. Retain a description of inspection methods along with the maintenance records for review when requested.

9.3 Intake Air System - Prior to each stand calibration test, inspect the intake air barrel for rust and debris. This may be done through either of the pipe flanges, using a borescope or some other optical means. Remove any foreign material.

9.4 Cooling System:
9.4.1 Whenever visual inspection indicates the need, remove all mineral deposits and oil from the cooling system. Make the initial coolant charge at the start of the test with distilled or de-ionized water and a rust inhibitor (Penncol 2000) (see 7.3). The cooling system shall remain full during all shutdowns that do not require the cooling system to be drained.

9.4.2 Make any make-up coolant additions throughout the test with the same treated water solution. Monitor the cooling system visually at the glass or plastic tube in the 1Y504 water outlet line assembly. At any indication of vapor formation, the coolant will have a clouded appearance. Should this occur during a test, shutdown the engine and check for air leakage on the suction side of the water pump or combustion gas leakage in the cylinder head. No air is permitted in the system.

9.5 Engine Cooling System Cleaning - Clean the cooling system when visual inspection shows the presence of oil or grease, mineral deposits, or rust. Heads may be cleaned when either on or off the engine. Use the following procedure:
9.5.1 Operate the engine long enough to reach oil and water operating temperatures; drain the cooling system.

9.5.2 Fill the cooling system with a solution of 450 g (1 lb) commercial sodium bisulfate (Na2SO4) to 19 L (5 gal) of water; then run the engine at operating temperature for 1/2 h.

9.5.3 Drain and flush the engine with fresh water, and drain the water from the system.

9.5.4 Fill the cooling system with a solution of 450 g (1 lb) of tri-sodium phosphate (Na3PO4) to 38 L (10 gal) of water; operate the engine for 5 min to ensure complete mixing of the Na3PO4 solution with any material left from the previous flush.

9.5.5 Drain the engine, flush with clear water, and drain after flushing.

9.5.6 Disassemble the engine, and prepare for the next test.

NOTE 2 - If the purpose of the system cleaning is to descale only, 9.5.4 and 9.5.5 can be omitted.

9.6 Instrumentation Calibration Requirements:
9.6.1 General Requirements:
9.6.1.1 Calibrate all facility read-out instrumentation used for the test immediately prior to commencing a test stand calibration. Instrumentation calibrations prior to subsequent stand calibration tests (that is, those that follow a failed or invalid first attempt) are at the discretion of the test laboratory. Make these calibrations part of the laboratory record (refer to Tables 2-4 for specifications).

9.6.1.2 Calibrate on a yearly basis all temperature, pressure, flow, and speed measurement standards with instruments traceable to a national bureau of standards (for example, the National Bureau of Standards and Technology or its successor agency for labs operating in the United States). Maintain records of all calibrations for a minimum of two years.

9.6.2 Specific Humidity Requirements:
9.6.2.1 Calibrate the primary laboratory humidity measurement system during the first 24 h of each individual stand calibration test using a chilled-mirror dew point hygrometer with an accuracy of at least +/- 0.55°C at 24°C (+/- 1°F at 75°F) dew point. The calibration consists of a series of paired comparison measurements between the primary system and the chilled-mirror dew point hygrometer. The comparison period lasts from 20 min to 2 h with measurements taken at 1 to 6 min intervals, for a total of 20 paired measurements. The measurement interval should be appropriate for the time constant of the humidity measuring instruments.

9.6.2.2 The location of the hygrometer tap is shown in Fig.A1.28. The sample line may require insulation to prevent dropping below dew point temperature and shall not be hygroscopic. The flow rate shall be verified to be within the equipment manufacturer's specification.

9.6.2.3 All measurements taken with the dew point hygrometer are at atmospheric pressure and corrected to standard conditions (101.12 kPa [29.92 in. Hg]) using the perfect gas law or Table X1.1 to Table X1.9 in Appendix X1. Compute the difference between each pair of measurements and use to form a mean and standard deviation. The absolute value of the mean difference shall not exceed 0.648 g (10 grains), and the standard deviation shall be less than or equal to 0.324 g (5 grains). Both of these requirements shall be met for the primary humidity measurement system to be considered calibrated. If either of these requirements cannot be met, the laboratory should investigate the cause, make repairs, and recalibrate. Maintain the calibration data for two years.

9.6.2.4 Recommended Practice - Install drain taps at the low points of the combustion air system and keep open during shut-down and warm-up.

9.6.3 Specific Coolant Flow Requirements:
9.6.3.1 As a calibration standard, each test lab is required to maintain at least one Barco venturi flow meter configured as shown in Fig. A1.8 and described in 6.16. On a yearly basis, calibrate this Barco (with its inlet and outlet piping) with an instrument traceable to a national bureau of standards (for example, the National Bureau of Standards and Technology or its successor agency for labs operating in the United States). The inlet and outlet piping shall remain with this Barco assembly.

9.6.3.2 During the break-in prior to each calibration test, place this calibrated Barco assembly in the standard mounting position. Adjust the coolant flow bypass valve until the readout equipment being used registers the differential pressure that corresponds to 57.9 L/min (15.3 gal/min) for this calibrated Barco assembly.

9.6.3.3 After break-in, replace the calibrated Barco assembly with the stand's running Barco assembly. Do not re-adjust the coolant flow bypass valve. Maintain whatever differential pressure is registered with the stand Barco at this point throughout the duration of the test. Test all non-reference oils with this stand Barco assembly run at this differential pressure. If desired, adjust any readout equipment to make this differential pressure correspond to 57.9 L/min (15.3 gal/min).

9.7 Engine Crankcase Cleaning - Flush the engine prior to each new test. The objective is to remove all deposits from all surfaces of all engine cavities prior to each test. In some instances, extra cleaning may be required. A finger-wiping check may be made on less accessible engine surfaces from time-to-time to determine if the engine is clean.

9.8 Additional Oil Filter - Install a full-flow paper element oil filter in the flushing pump unit to remove engine wear particles during engine flush. Such particles have been known to cause piston scuffing during subsequent testing.

9.9 Flushing Procedure Components - Conduct the engine flushing procedure with the components shown in Fig. A1.12 through A1.19 (the design for mobilizing the flushing pump arrangement, Fig. A1.13, is optional). Figure A1.17 (Views A and B) illustrates the use of the flushing components.

9.10 Flushing Procedures - Use the following flushing procedure:
9.10.1 Rotate the crankshaft until the top end of the connecting rod is below the cylinder block bore in the top of the crankcase. Install the poly(methyl methacrylate) (PMMA) or clear plastic cover (Fig. A1.12 on the top surface of the crankcase, as shown in Fig. A1.17 (View A).

9.10.2 For First Stage Flushing with Mineral Spirits:
9.10.2.1 Install a clean 1Y5700 element in both the engine and flushing pump oil filter housings.

9.10.2.2 Connect the flushing pump (Fig.A1.13) outlet hose to the engine oil cooler drain location.

9.10.2.3 Remove breather assembly 1Y2592 (top portion of side cover assembly) and clean separately by soaking in mineral spirits. Air-dry.

9.10.2.4 Insert the 1Y5 rocker shaft oil line in the center opening of the clear plastic cover (see Fig. A1.12).

9.10.2.5 Place the flushing pump inlet line in a clean supply tank (sample location illustrated in Fig.A1.13) containing 7.6 L (2 gal) of mineral spirits. Open the crankcase drain, start the flushing pump, and run this flush material through the engine into a drain pan one time. Do not recirculate.

9.10.2.6 Close the crankcase drain and connect the flushing pump inlet line to the crankcase drain.

9.10.3 For Second Stage Flushing and Recirculating with Cleaning Mixture - Mix 1.9 L (1/2 gal) of dispersant engine cleaner (see Footnote 19) with 5.7 L (1 1/2 gal) of mineral spirits to obtain 7.6 L (2 gal) of flushing solution. Add this mixture to the crankcase.
9.10.3.1 Connect the flushing pump outlet line to the engine oil cooler drain location. Open the crankcase drain valve, start the flushing pump, and circulate the flushing solution through the engine for approximately 15 min. Turn off the pump. (Do not drain the flushing solution from the crankcase.)

9.10.3.2 Close the oil cooler drain valve, disconnect the flushing pump outlet hose from the oil cooler drain location, and connect to the crankcase sprayer (Fig. A1.14).

9.10.3.3 Remove the 1Y5 oil line from the cover hole, insert the crankcase sprayer through the opening in the PMMA cover. Start the flushing pump, and spray the interior of the crankcase by slowly moving the sprayer around and into all accessible areas of the crankcase (see Fig. A1.17, View A) for approximately 10 min. Turn off the pump. (Do not drain the flushing solution from the crankcase).

9.10.3.4 Remove the 1/2 in. pipe plug from the modified 1Y1990 governor housing cover (see Fig. A1.15). Insert the crankcase sprayer (Fig. A1.14) through the opening in the governor housing cover, start the pump, and spray the interior of the governor housing for approximately 10 min. Turn off the pump. (Do not drain the flushing solution from the crankcase.)

9.10.3.5 Remove the oil filler spout assembly from the front of the crankcase, and install the front cover sprayer (see Fig.A1.16) as shown in Fig. A1.17.

9.10.3.6 Connect the flushing pump outlet to a 64 mm x 13 cm (1/2 in. x 5 in.) pipe on the front cover sprayer (see Fig. A1.16). Start the flushing pump, and spray the interior of the front cover for approximately 10 min. Drain the crankcase, governor, oil filter, and oil cooler; and discard the flushing solution.

9.10.4 Using Mineral Spirits - Repeat 9.10.2.4 through 9.10.2.6 until the mineral spirits discharge is clean. (Three to four flushes with mineral spirits are usually sufficient to remove all traces of the flushing solution from the engine.) Drain the mineral spirits from the crankcase, governor housing, oil filter, and oil cooler.

9.10.5 Test Oil Flushing - When engine is to be used immediately:
9.10.5.1 Prepare for the flush with the test oil by blocking off the 1Y5 oil line to the rocker arm shaft and installing the 6.4 mm (1/4 in.) fitting (see Fig. A1.18) on the open end of the line. Close all drain openings.

9.10.5.2 Using the flushing pump, add 4.7 L (5 qt) of test oil to the engine crankcase through the engine oil cooler.

9.10.5.3 Connect the flushing pump outlet to the engine oil cooler drain location. Start the flushing pump, and force any mineral spirits in the system out the crankcase drain. After the mineral spirits have been forced out of the system, connect the inlet line of the flushing pump to the crankcase drain. Install the dummy piston (reference service manual SENR2074) and the assembled cylinder liner and block assembly or the alignment fixture specified in Fig.A1.19. Re-install the oil filler spout and pipe plug in the modified governor housing cover (see Fig.A1.15).

9.10.5.4 Open the crankcase drain and start the flushing pump. Set and maintain the oil pressure at 207 kPa (30 psi). With the starter or dynamometer, turn the engine over for 1 min. Turn off the pump, and drain all oil from the engine crankcase, governor housing, oil filter, and oil cooler. Discard the oil drained.

9.10.5.5 Charge the engine again with 4.7 L (5 qt) of test oil, and repeat the procedure described in 9.10.2. During this flush, check the alignment of the piston cooling nozzle and adjust, if necessary. Before any such adjustment, make sure that the oil-stream condition has stabilized, that is, a steady stream of oil impinges the piston indicating that the oil pressure has attained a constant value. After draining the oil, install a clean element in the engine oil filter housing. Reinstall crankcase breather assembly 1Y2592.

9.10.6 Test Oil Flushing - When the test oil is not available and the engine test start will be delayed: follow the steps up to 9.10.5.2. However, in 9.10.5.2, use buildup oil 22,11 in place of test oil. When a test oil is scheduled for the engine, perform the following steps:
9.10.6.1 Connect the flushing pump outlet to the engine oil cooler drain location. Using the flushing pump, add 4.7 L (5 qt) of test oil to the engine crankcase through the engine oil cooler. Start the flushing pump, and force the build-up oil out the crankcase drain. After the build-up oil has been forced out of the system, connect the inlet line of the flushing pump to the crankcase drain. Set and maintain oil pressure at 207 kPa (30 psi). By hand, turn the engine five revolutions, and continue to run the pump for 4 min. Turn off the pump, and drain all oil from the engine crankcase, governor housing, oil filter, and oil cooler. Discard the oil drained.

9.10.6.2 Repeat the procedure described in 9.10.6.1. After draining the oil, install a clean element in the engine oil filter housing and prepare the engine for break-in.

9.10.7 An instruction sheet for technician use during the engine cleaning is shown in Fig.2.

9.11 Piston Cleaning Preparation - Clean new pistons using the following procedure before the installation of rings and final installation into the engine:
9.11.1 Spray with mineral spirits and dry with compressed air. (Warning - High concentration of vapors should be avoided. Use vented hood, face shield, gloves (same precautions as for gasoline).)

9.11.2 Using a lint-free cloth, wipe clean the entire piston with pentane, paying special attention to ring groove and land areas. Allow the piston to air dry.

9.11.3 Wipe the piston with Mobil EF-411 before final installation into the engine.

9.12 Cylinder Head:
9.12.1 Valve Guide Bushings - Remove and replace the 1Y448 and 1Y449 valve guide bushings with 1Y457 valve guide bushings (inlet) and 1Y469 valve guide bushing (exhaust). The new guides have the I.D. (inside diameter) threaded and require either reaming (see 9.12.1.2) or honing (see 9.12.1.3) after installation in the cylinder head. The required procedure is as follows:
9.12.1.1 Install the 1Y469 and 1Y457 bushings into the bores in the cylinder head.

9.12.1.2 Ream the I.D. of both bushings in successive steps with the following reamers as required to obtain the clearances listed in 9.12.1.4: 12.52 mm (0.4930 in.), 12.55 mm (0.4940 in.), 12.57 mm (0.4950 in.), 12.59 mm (0.4955 in.), 12.60 mm (0.4960 in.), and 12.61 mm (0.4965 in.).

9.12.1.3 Hone valve guide I.D. by using mandrel mounted honing stones. A continuous flow of honing oils is required. Turn the mandrel at slow speed (300 to 400 r/min) until the final size, as listed in 9.12.1.4 is obtained. In general, honed guides produce more uniform stem-to-guide clearances, resulting in longer service life of valves and guides.

9.12.1.4 The reamed stem-to-guide clearance shall be 0.013 to 0.051 mm (0.0005 to 0.0020 in.). The honed stem-to-guide clearance shall be 0.025 to 0.051 mm (0.0010 to 0.0020 in.). All measurements shall be made using a direct reading dial bore gage in the guide and micrometer on the valve stem. Valve stem drag shall not exceed 26 N (6 lbs).
(1) Usual final size for intake guide: 12.59 or 12.60 mm (0.4955 or 0.4960 in.).
(2) Usual final size for exhaust guide: 12.57 or 12.59 mm (0.4950 or 0.4955 in.).

9.12.1.5 Thoroughly clean the reamed valve guide bushing with mineral spirits or hot water, detergent, and stiff brush.

9.12.1.6 Grind the valve seats and faces in accordance with the dimensions for the 1Y73 engine as specified in the Caterpillar, Inc. Service Manual for Single Cylinder Oil Test Engine for Diesel Lubricants, Form No.SENR2074.

9.12.1.7 Thoroughly clean the entire cylinder head and valves after grinding. Prelube the valve stems and guides with Mobil EF-411.

9.12.1.8 Insert a rubber O-ring (p/n 8F9206) into the 3H5867 valve spring retainer for all 1M-PC tests. Inspect this O-ring for hardness or cracking during cylinder head reconditioning and replace as necessary.

9.12.2 Precombustion Chamber Inspection and Maintenance - Maintain the orifice diameter of the precombustion chamber, Part Number 6H1528, at 7.620 +/- 0.025 mm (3.300 +/- 0.001 in.). Inspect and measure the orifice prior to installation of the cylinder head on the engine at the start of the 1M-PC test method. Any measurement that is out of the 7.620 +/- 0.025 mm (0.300 +/- 0.001 in.) diameter limit or shows any indication of ovality requires the replacement of the precombustion chamber.

9.13 Fuel Nozzle - Inspect the nozzle tip for carbon build-up and deformed surfaces, and replace questionable nozzles. Check the valve opening pressure before each test. Refer to the service manual for additional information.

9.14 Measurement - Measure the piston, rings, cylinder liner, and fuel timing before the start and at the completion of the test. Use a new piston, ring set, and cylinder liner for each new test. Measure and report compression ratio at the start of the test.
9.14.1 Initial Cylinder Liner Measurements - Assemble the cylinder head, block, and liner with specified stud nut torque.
9.14.1.1 Measure the 1Y3590, 1Y3995, or 5H5657 liner in both transverse and longitudinal directions relative to the crankshaft to ensure that the out-of-round and taper conditions are within specified tolerances. Take measurements from underneath at 25 mm (1 in.) intervals for 23 cm (9 in.), starting 25 mm (1 in.) from the top of the liner.

9.14.1.2 Determine the out-of-round condition for each 25 mm (1 in.) interval: It shall not exceed 0.038 mm (0.0015 in.).

9.14.1.3 The taper measurement compares the diameters from 25 mm (1 in.) to 23 cm (9 in.) for both transverse and longitudinal positions; the maximum difference shall not exceed 0.051 mm (0.0020 in.).

9.14.1.4 Measure liner surface finish. Record all measurements on the Liner Measurements form of the test report.

9.14.2 Post Test Wear Measurements for Liner Step Wear - At the end of the test, determine the liner wear step in both transverse and longitudinal directions by using a surface profile measurement. Remove deposits on the liner above the piston ring travel. Take transverse and longitudinal measurements at the wear step location approximately 20 to 25 mm (0.75 to 1 in.) from the top of the liner at four locations. Record the measurements as liner wear on the Liner Measurements form of the test report.

9.14.3 Ring End Gap - Determine wear on the rings by measuring the gap width before and after the test with the ring confined in a 13.02 cm (5.125 in.) inside diameter ring gage. Remove all deposits from the end of the rings after the deposit inspection and before the final ring gap measurements. Record the difference between these two measurements as ring gap increase or wear on the Ring Measurements form of the test report.

9.14.4 Ring Side Clearance:
9.14.4.1 Before and after the test, measure the piston ring side clearance of all rings. Make the after-test measurements before the rings are removed from the piston and with the accumulated deposits in place. Record all measurements on the Ring Measurements form of the test report. Measure side clearances as follows:
(1) Insert thickness (feeler) gage underneath the piston ring.
(2) Slide gage around the piston while holding ring in gently at the point of measurement to determine the minimum and maximum clearance to the nearest 0.013 mm (0.0005 in.)
(3) Use of gage requires firm but smooth horizontal pull. If gage movement is not firm or requires undue stress to move it, adjust the thickness up or down as required.
(4) Repeat 9.14.4.1 (1), (2), and (3), being careful not to force ring or gage against any deposit build up.

9.14.4.2 Calculate ring side clearance loss from:
Maxbefore - Maxafter or Minbefore - Minafter
whichever is greater. Report zero in cases where loss of side clearance is less than zero.

9.14.4.3 Side clearance specification for new parts is:
(1) Top ring, 0.185 mm maximum (0.0073 in.) to 0.114 mm minimum (0.0045 in.)
(2) Two intermediate rings, 0.122 mm maximum (0.0048 in.) to 0.076 mm minimum (0.0030 in.)
(3) Oil ring, 0.076 mm maximum (0.0030 in.) to 0.038 mm minimum (0.0015 in.)

9.14.5 Compression Ratio:
9.14.5.1 Determine the compression ratio before starting the test. Essential to measuring compression ratio is piston-to-head clearance. Determine this dimension by using 2.41 to 2.67 mm (0.095 - 0.105 in.) diameter lead shot. These lead pieces are held on the top of the piston with light grease. The location pattern for the lead shot is shown in Fig.A1.20. With the piston approximately halfway up on the stroke the cylinder head is installed and torqued to the standard torque specifications. Turn the engine over top center by hand, remove the head and block assembly, and measure the thickness of the lead shot to obtain the piston-to-head clearance. The average piston-to-head clearance shall measure 1.30 +/- 0.127 mm (0.051 +/- 0.005 in.).

9.14.5.2 Use multiple block gaskets (1Y3698) to adjust clearance. If the piston-to-head measurement exceeds the tolerance specification, check the crankshaft main and rod journals, connecting rod and main bearings, piston pin, and bushing for excessive wear. If these dimensions are not all within specifications, consult Caterpillar before any standard 1M-PC test is started.

9.14.6 Piston Ring Gap Location - Install the piston in the engine in accordance with standardized ring gap location. Use the 1Y3589 piston and 1Y3588 ring set. See Fig. A1.22 for ring gap locations.