ASTM D6891 Standard Test Method for Evaluation of Automotive Engine Oils in the Sequence IVA Spark-Ignition Engine
9. Preparation of Apparatus
NOTE 7 - This section details those recurring preparations necessary for test operation. This section assumes the engine test stand facilities and other hardware described in Section 6 are in place.

9.1 Test Stand Preparations:
9.1.1 Instrumentation Calibration - Calibrate all sensors and indicators before or during the test for the type instrumentation used. See Section 10 for the calibration requirements.

9.1.2 Oil Cooler Cleaning - Use clean mineral spirits followed by forced-air drying to clean the oil cooler, if required (see 6.1.3).

9.1.3 Air Cleaner Filter - Replace the air cleaner filter element every eight tests, or more frequently if intake air pressure is insufficient.

9.1.4 Draining Exhaust Piping - Prior to the start of each test, drain the low point of the exhaust piping to eliminate water accumulation. Drain water during a test if exhaust pressure control becomes unstable.

9.1.5 External Hose Replacement - Inspect all external hoses used on the test stand and replace any hoses that have become unserviceable. Check for internal wall separations that could cause flow restrictions. Inspect and replace the oil cooler coolant hoses when the oil cooler is replaced (every 16 tests).

9.1.6 Stand Ancillary Equipment - Service the dynamometer and driveline components, as required. The dynamometer torque measurement shall be accurate (no unaccounted forces from hoses, load cell temperature gradients, or trunnion bearing hysteresis).

9.2 General Engine Assembly Preparations - Follow and complete the assembly preparation functions shown in Table 6. Different laboratories and engine assemblers may complete the functions in slightly different sequences. Perform the functions in a specific manner or at a specific time in the assembly process as shown in Table 6. Complete any assembly instructions not detailed below according to the instructions in the Nissan Service Manual. Follow the bolt torque specifications shown in Table 6.

9.3 Cylinder Head Preparations - Modify, clean, assemble, and calibrate new test engine cylinder heads before using the cylinder head for testing purposes. Record the measurements shown in 9.3.3 on the appropriate form.
9.3.1 Cylinder Head Modification - Assess the cylinder head oil gallery from the intake side of the head through the vertical passage, centered front-to-rear. Drill this access port in a bossed area of the head and located 10 mm +/- 1 mm upward from the deck surface of the head. Drill and tap the access port to accept a 3.2 mm close pipe nipple.

9.3.2 Cylinder Head Cleaning - Complete the modification shown in 9.3.1, then thoroughly clean the cylinder head using mineral spirits spray. Clean the valve guide bores and oil passages using a nylon bristle brush in conjunction with the mineral spirits spray (see 6.1.3). Then rinse the head with a clear water spray, and dry with forced air.

9.3.3 Camshaft Journal Clearance - Use only the vertical measurements to determine the overall cam journal to bearing clearance (front and rear). This clearance may not exceed 0.120 mm. Replace the cylinder head or camshaft, or both, if the clearance exceeds 0.120 mm.
9.3.3.1 Camshaft Bearing Bore Measurements - Install cam-bearing caps, without the camshaft, with rocker shafts and tighten the lubricated cap bolts to 39 N·m.
(1) When the cylinder head is new, perform a comprehensive set of measurements of the five cam bearing bores to ensure the bores are sized to specification, and that the bores are round and not tapered. Measure the front and rear of each cam bore in three directions: vertical and two measurements at 45° from vertical. This results in six measurements for each cam bore. The standard inner diameter specification is 33.000 mm to 33.025 mm. Run-out and taper shall not exceed 0.025 mm.
(2) After the first test on a cylinder head, use only the vertical dimension of the front and rear of each cam bore (from the comprehensive measurements performed on the new cylinder head) to determine the cam journal to bearing bore clearance before subsequent tests.

9.3.3.2 Camshaft Journal Measurements - Measure the front and rear outer diameters of each of the five camshaft journals. The standard outer diameter is (32.935 to 32.955) mm. Use these measurements to calculate cam journal to bearing bore clearance.

9.3.3.3 Camshaft End Play - With the camshaft installed in the cylinder head, measure the camshaft endplay with a dial indicator. If the endplay exceeds 0.07 mm to 0.20 mm, do not use that cylinder head/camshaft combination.

9.3.4 Cylinder Head Assembly - Assemble the cylinder head using the instructions in the Nissan Service Manual. Lap the valve faces to their respective valve seats to ensure a proper seal. Using a new cylinder head precludes replacing or machining the valves, valve guides, and valve seats. Use SAE 20 API SA lubricant to lubricate the valve stems and valve guides upon assembly.

9.3.5 Initial Valve Spring Screening - Measure the force on the unassembled valve spring calibration device. The valve spring parameters shall be within the specifications show in Table 7. Determine the final valve spring assembled force with the valve springs installed in the cylinder head (see 9.3.6). Springs slightly outside the unassembled force specification can be within the assembled force specification when installed in the cylinder head using shims under the springs.

9.3.6 Installed Valve Spring Calibration - Lubricate each valve seal and valve stem with SAE 20 API SA oil. Install the valve seal over the end of the valve stem with a plastic installation cap in place. Carefully seat the seals fully on the guides. Install pre-screened valve springs and retainers. When installing the valve springs and retainers, do not compress the springs excessively. Excessive spring compression may damage the valve seals.
9.3.6.1 Assembled Force Calibration - Measure and record the assembled valve spring loading with the valve springhead calibration fixture shown in Fig.10 and the part number in Annex A6.

9.3.6.2 The procedure detailed below includes measuring each installed valve spring at two deflection points (see Table 8).
(1) Check the apparatus load cell calibration for accuracy.
(2) Install the cylinder head holding fixtures (see Annex A7) for the test cylinder head.
(3) Position the test cylinder head in the holding fixture with intake valve springs accessible.
(4) Install the rocker cover gasket rail extension bracket on the test cylinder head.
(5) Starting with the intake valve spring No.1 (far right), position the air cylinder and load cell on valve tip to allow compressing of the valve spring.
(6) Position the dial indicator with the plunger on the rocker cover gasket rail extension bracket.
(7) With no air pressure to the cylinder, the dial indicator shall read between 2.5 mm and 5.00 mm deflection pre-load against the rocker cover gasket rail extension bracket. This will allow determination of positive or negative valve displacement.
(8) Adjust the dial indicator face to position the needle at the zero mark with no air pressure to the air cylinder.
(9) Adjust the air regulator to provide enough air pressure to the air cylinder for compression of the valve spring to occur. If a valve spring has already been measured, then the air regulator should already be adjusted.
(10) Actuate and discharge the air cylinder in a rapid and consistent manner, several times, to compress the valve spring and assure proper movement of the valve-train components.
(11) Actuate the air cylinder and adjust the air regulator to decrease the air pressure to allow the valve to close to the fully seated position.
(12) Adjust the air regulator to gradually apply force to achieve exactly 1.27 mm valve opening. Record the indicated force in newtons at 1.27 mm.
(13) Continue to adjust the air regulator to gradually apply force to achieve exactly 9.86 mm valve opening. Record the indicated force in newtons at 9.86 mm.
(14) Discharge the air cylinder without adjusting the air regulator, and allow the intake valve to close to the fully seated position. Position the air cylinder/load cell to check the remaining seven-intake valve springs. Conduct Steps 5 - 13 for each remaining intake valve spring.
(15) Position the test cylinder head in the holding fixture with the exhaust valves accessible.
(16) Install the rocker cover gasket rail extension bracket on the cylinder head, and position the air cylinder and load cell to check the four exhaust valve springs. Conduct Steps 5 - 13 for each exhaust valve spring.
(17) Replace any springs that are too strong. Use shims to adjust springs to a higher installed force. Recheck spring calibration and record indicated force, in newtons, of any replaced or shimmed springs.

9.3.7 Vacuum Check - Prior to installing the cylinder head on the engine, conduct a vacuum check to ensure no leakage past the valves, and so forth. The method of checking is left up to the laboratory.

9.4 Short Block Preparations - Not normally required.

9.5 Short BlockAssembly - Use SAE 20 API SA grade oil as the assembly lubricant for inspection and reassemble the engine short-block.

9.6 Final Engine Assembly - Use the engine short-block assembly as received from Nissan. Alternatively, disassemble, inspect, and reassemble the engine short-block according to the Nissan Service Manual. For this test, maintain the piston ring end gaps to factory specifications. Do not increase the ring end gaps to elevate engine blowby. Observe the corrected blowby rate at 6.0 L/min to 10.0 L/min during the Stage I operating condition.
9.6.1 Cylinder Head Installation - The parts kit (see Annex A6) include the assembled new cylinder head. The valve seats and valve faces are machined to Nissan production specifications. Laboratory inspection may reveal the need to lap the valve seat and valve faces. Perform the following before assembling the cylinder head:
9.6.1.1 Stamp with a laboratory specific identification code.

9.6.1.2 Modify for measurement access to the cylinder head oil gallery (see 6.3.11.7).

9.6.1.3 Measure for cam bearing bore diameter, specification 33.000 mm to 33.025 mm.

9.6.1.4 Clean with mineral spirits and forced-air dried (see 6.1.3).

9.6.1.5 Reassemble according to the Nissan Service Manual. Use SAE 20 API SA grade oil to lubricate valve guides and valve stems. Install new valve seals.

9.6.1.6 Measure and adjust installed valve spring force to test specifications (see 9.3.5). Install the modified and measured cylinder head on the short-block using a new cylinder head gasket (see Annex A6). Torque the head bolts in proper sequence, and in five stages according to the Nissan Service Manual. Use an angle-meter torque wrench to properly torque the cylinder head bolts.

9.6.2 Pre-Test Cam Shaft Inspection and Measurement:
9.6.2.1 Visually inspect the pre-test camshaft lobes and bearing journals for rust, scratches, gouges, chipped areas, and other surface defects. Reject camshafts that are judged unsuitable for test.

9.6.2.2 Check the pre-test camshaft for straightness. With the camshaft supported by V-blocks at journal No(s).1 and 5, measure the camshaft run-out at the center journal. Reject the camshaft if the total indicator reading of the run-out exceeds 20 µm.

9.6.2.3 Using a profilometer to perform pre-test measurements, check the camshaft for lobe concavity, convexity, and taper across the nose of each camshaft lobe. Reject any camshaft that exhibits concavity or convexity of more than 4 µm in height or depth or taper of more than 10 µm in variation. The laboratory has the one-time option of sending any camshaft, including camshafts rejected per the above criteria, at their discretion, to OHT for regrinding. OHT regrinds camshafts according to Nissan specifications. All camshafts meeting the above specification can then be put into service. Any test run with a reground camshaft should be noted in the test report comment section.

9.6.3 Camshaft Installation - After modifying, cleaning, assembling and calibrating the cylinder head, install the measured test camshaft. Clean the camshaft with mineral spirits and forced-air dry (see 6.1.3). Coat the journals with SAE 20 API SA grade oil or new test oil. Coat the lobes with new test oil only. Do not use REO 926-2 or SAE 20 API SA to lubricate the lobes.
9.6.3.1 Install the test camshaft, camshaft journal caps and dummy rocker shafts, and torque to 39 N·m. Install the camshaft sprocket and snug the sprocket bolt (do not torque to specification).

9.6.3.2 Measure and record the camshaft endplay and the camshaft sprocket run-out (see Annex A8).

9.6.3.3 Temporarily remove the test camshaft, camshaft sprocket, camshaft journal caps, and utility rocker shafts.

9.6.3.4 Pre-fill the cavities of the cylinder head under the camshaft with new test oil.

9.6.3.5 Oil the camshaft journals and journal bores with SAE 20 API SA or new test oil and install the test camshaft.

9.6.3.6 Install the camshaft journal caps in their proper positions.

9.6.3.7 Install the rocker shaft assemblies and loosely screw the bolts. Do not tighten the bolts.

9.6.3.8 Install the camshaft sprocket and timing chain, aligning the punch-mark with the glaring link. Torque the camshaft bolt to 135 N·m using the appropriate cam sprocket holding tool.

9.6.3.9 Center each individual rocker arm on its respective cam lobe, and then snug the ten rocker shaft bolts and torque to 39 N·m using the torque sequence in the Nissan Service Manual.

9.6.3.10 After installing the camshaft pour new test oil over the rocker arms, rocker shafts, and camshaft. Excess oil will drain through the open oil pan drain-valve.

9.7 Replacement of Valve-train Wear Parts - The valve-train wear tests is a flush-and-run type procedure, except replace the valve-train test parts for each test. Use the following procedure when replacing these parts:
9.7.1 Removal of Valve-train Wear Parts:
9.7.1.1 Disconnect wiring or hoses that hinder access to the rocker cover.

9.7.1.2 Remove the crankshaft pulley guard.

9.7.1.3 Remove the blowby fresh airline and the spark plug wire loom from the rocker cover.

NOTE 8 - At Southwest Research Institute (SwRI), client test oil is poured over valve-train parts at test start before Flush 1, NOT during parts installation.

9.7.1.4 Remove the rocker cover.

9.7.1.5 Remove all four spark plugs.

9.7.1.6 Rotate the engine by hand to set piston No.1 at top dead center on its compression stroke (align the timing indicator with 0° at the yellow mark on the crankshaft pulley). Position the dowel pin on camshaft front at the 12:00 position and align the punch-mark on the camshaft sprocket with the glaring link on the timing chain. This may require rotating the engine several times until the mark and glaring link line up.

9.7.1.7 Remove the front hoist bracket from the cylinder head. It may hang from the ground straps.

9.7.1.8 Remove the half-moon rubber plug from the front of the cylinder head.

9.7.1.9 Install the timing chain wooden wedge tool between timing chain at the tensioner using a large screwdriver to set in place.

9.7.1.10 Remove the camshaft bolt and sprocket using a 24 mm impact deep socket.

9.7.1.11 Remove the ten rocker shaft bolts according to the Nissan Service Manual.

9.7.1.12 Carefully remove the rocker shafts and rocker arms. Avoid touching the rocker arm pads. The rocker arms shall remain assembled on the rocker shafts.

9.7.1.13 Remove the five camshaft journal caps. Number the caps for their location.

9.7.1.14 Carefully remove the test camshaft without damaging the lobes. Avoid touching the camshaft lobes.

9.7.1.15 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.

9.7.1.16 Bring the end-of-test parts, including the assembled rocker shaft assemblies to the engine disassembly area. Before disassembling the used rocker shaft assemblies, properly label the rocker arms.

9.7.1.17 Disassemble the rocker shaft assemblies.

9.7.1.18 Remove the reusable retainer clips from the used rocker shafts.

9.7.1.19 Clean the end-of-test camshaft and rocker arms with mineral spirits and pentane if necessary, then forced-air dry (see 6.1.3). Deliver the cleaned camshaft to the measurement room, and the cleaned rocker arms to the rating area or place them in a desiccator.

9.7.2 Installing New Valve-train Test Parts:
9.7.2.1 Obtain the new test parts, including the premeasured test camshaft. See Annex A6 for a new parts listing with their corresponding part numbers for each turnaround.

9.7.2.2 Number the new rocker arms E1 to E4 and I1 to I8.

9.7.2.3 Clean the new camshaft, rocker shafts and rocker arms, as well as the used retainer clips, camshaft journal caps, camshaft sprocket, rocker cover and all bolts with mineral spirits and forced-air dry (see 6.1.3).

9.7.2.4 Perform and record camshaft bearing journal diameter measurements.

9.7.2.5 Perform a bleed down of the rocker arms with built in hydraulic lash adjusters. Place the rocker arms in a container or vacuum chamber, fully submerging them in SAE 20 API SA grade oil. Using a vacuum chamber reduces the minimum soak time from 1 h to 5 min. Once the rocker arms are air bled, do not place them on their sides. Orient the rocker arms in their natural engine position.

9.7.2.6 Assemble the new rocker arms and used retainer clips on the new rocker shafts according to the Nissan Service Manual.

9.7.2.7 Install the five camshaft journal caps and bare rocker shafts, using the designated utility rocker shafts, and torque to 39 N·m.

9.7.2.8 Perform and record camshaft bearing bore diameter measurements.

9.7.2.9 Remove the camshaft journal caps and utility rocker shafts.

9.7.2.10 Install the test camshaft, camshaft journal caps and dummy rocker shafts, and torque to 39 N·m. Install the camshaft sprocket and snug the sprocket bolt, and do not torque to specification.

9.7.2.11 Measure and record the camshaft endplay and the camshaft sprocket run-out according to the Nissan Service Manual.

9.7.2.12 Remove the test camshaft, camshaft sprocket, camshaft journal caps, and dummy rocker shafts.

9.7.2.13 Pre-fill the cavities of the cylinder head under the camshaft with new test oil.

9.7.2.14 Oil the camshaft and journal bores with new test oil and install the test camshaft.

9.7.2.15 Install the camshaft journal caps in their proper positions.

9.7.2.16 Install the rocker shaft assemblies and loosely screw the bolts. Do not yet tighten the bolts.

9.7.2.17 Install the camshaft sprocket and timing chain, aligning the punch-mark with the glaring link. Using the appropriate cam sprocket holding tool, torque the camshaft bolt to 135 N·m.

9.7.2.18 Center each individual rocker arm on its respective cam lobe, then snug the ten rocker shaft bolts and torque to 39 N·m using the torque sequence as shown in the Nissan Service Manual.

9.7.2.19 After installation pour new test oil over the rocker arms, rocker shafts and camshaft. Excess oil will drain through the open oil pan drain-valve.

9.7.2.20 Inspect the half-moon rubber plugs found on the front and rear of the cylinder head. Replace the plugs if necessary.

9.7.2.21 Install the half-moon rubber plug on the front of the cylinder head. Apply the proper amount of the Nissan silicone gasket maker to the bottom of the plug. Repeat for the half-moon rubber plug found on the rear of the cylinder head.

9.7.2.22 Inspect the rocker cover gasket, and replace if necessary.

9.7.2.23 Install the rocker cover and torque in sequence to 8 N·m as shown in the Nissan Service Manual.

9.7.2.24 Reinstall the blowby fresh airline on to the rocker cover and tighten the clamp.

9.7.2.25 Install spark plug wire loom and reconnect any other wiring or hoses.

9.7.2.26 Install the front hoist bracket and torque the nuts to 20 N·m.

9.7.2.27 Install new spark plugs (see Annex A6). Gap the plugs to 0.99 mm and torque to 14 N·m.

9.7.2.28 Install the front pulley guard.