Engine Mechanical: Overhaul Infiniti QX50 I

Disassembly

1. Remove intake manifold collector. Refer to " «EXPLODED VIEW»(ref-616997-S34377469492014052000000) ".
2. Remove intake manifold. Refer to " «EXPLODED VIEW»(ref-616997-S22610846402014052000000) ".
3. Remove exhaust manifold. Refer to " «EXPLODED VIEW»(ref-616997-S21882478872014052000000) ".
4. Remove oil pan (lower). Refer to " «EXPLODED VIEW»(ref-616997-S14651106792014052000000) ".
5. Remove ignition coil, spark plug and rocker cover. Refer to " «EXPLODED VIEW»(ref-616997-S11275739352014052000000) ".
6. Remove fuel injector and fuel tube. Refer to " «EXPLODED VIEW»(ref-616997-S36219619912014052000000) ".
7. Remove timing chain. Refer to " «EXPLODED VIEW»(ref-616997-S39914347982014052000000) ".
8. Remove rear timing chain case. Refer to " «EXPLODED VIEW»(ref-616997-S15519648222014052000000) ".
9. Remove camshaft (EXH) and VVEL ladder assembly. Refer to " «EXPLODED VIEW»(ref-616997-S36741960892014052000000) ".
10. Remove cylinder head. Refer to " «EXPLODED VIEW»(ref-616997-S39877413362014052000000) ".

Assembly

Assemble in the reverse order of disassembly.

Scheme 171

Note. VVEL ladder assembly cannot be replaced as a single part, because it is machined together with cylinder head assembly.

Scheme 172

Scheme 173

Scheme 174

Scheme 175

Scheme 176

1. Remove rocker covers (bank 1 and bank 2). Refer to " «EXPLODED VIEW»(ref-616997-S11275739352014052000000) ".
2. Remove VVEL actuator sub assembly as follows: CAUTION: VVEL actuator sub assembly and VVEL control shaft position sensor are nonreusable. Never remove them unless they are required. Remove VVEL control shaft position sensor. Turn control shaft to the large lift side and fix it in order to prevent the interference of the stopper surface. If control shaft cannot be moved, set crankshaft in position referring to the information below. (To displace cam nose) Bank 1: Turn 120 degrees from no. 1 cylinder at TDC Bank 2: No. 1 cylinder at TDC Fix two flat areas (C) of control shaft with a wrench to remove mounting bolts of control shaft. CAUTION: During the operation, never allow a wrench to interfere with other parts. Fix control shaft to prevent the interference of the stopper surface. Remove VVEL actuator sub assembly. Loosen mounting bolts in the reverse order as shown in the figure below. CAUTION: When removing, prepare wastes because oil spills. When installing, be careful with VVEL actuator sub assembly (bank 2) mounting bolt No. 1 because its length is different. Remove actuator bracket (rear). Loosen mounting bolts in the reverse order as shown in the figure below.
3. Remove front timing chain case, camshaft sprockets, and timing chain. Refer to " «EXPLODED VIEW»(ref-616997-S39914347982014052000000) ".
4. Remove rear timing chain case. Refer to " «EXPLODED VIEW»(ref-616997-S15519648222014052000000) ".
5. Remove VVEL ladder assembly. Loosen mounting bolts (gold color) in the reverse order as shown in the figure below. CAUTION: Never loosen adjusting bolts and mounting bolts (black color). When removing VVEL ladder assembly, hold the drive shaft from below so as not to drop it.
6. Remove camshaft (EXH).
7. Remove valve lifter. Identify installation positions, and store them without mixing them up.
8. Remove timing chain tensioners (secondary) (1) from cylinder head. Remove timing chain tensioners (secondary) with its stopper pin (C) attached. NOTE: Stopper pin should be attached when timing chain (secondary) is removed.
9. Remove oil filter from cylinder head, if necessary.

Scheme 177

Scheme 178

Scheme 179

Scheme 180

Scheme 181

Scheme 182

Scheme 183

Scheme 184

Scheme 185

Scheme 186

Scheme 187

Scheme 188

Scheme 189

Scheme 190

Scheme 191

Scheme 192

1. Install timing chain tensioners (secondary) (1) on both sides of cylinder head. Install timing chain tensioner with its stopper pin (C) attached. Install timing chain tensioner with sliding part facing downward on cylinder head (bank 1), and with sliding part facing upward on cylinder head (bank 2).
2. Install oil filter (1), if removed. Do not project from the cylinder head (2) surface.
3. Install valve lifter. Install it in the original position.
4. Install camshaft (EXH). Distinction between camshaft (EXH) (bank 1 and bank 2) is performed with the identification mark. Bank Paint marks Identification mark (F) M1 (C) M2 (D) M3 (E) Bank 1 (A) No Blue Light blue 1 N Bank 2 (B) No Blue Light blue 1 P
5. Install VVEL ladder assembly as follows: CAUTION: Do not reuse O-rings. Apply a continuous bead of liquid gasket with tube presser (commercial service tool) to the cylinder head as shown in the figure below. Use Genuine RTV Silicone Sealant or equivalent. Refer to " «RECOMMENDED CHEMICAL PRODUCTS AND SEALANTS»(ref-616989-S14994929602014052000000) ". Tighten mounting bolts in the following step, in numerical order as shown in the figure below. Tighten bolts in numerical order as shown in the figure below. Torque Value: 1.96 N.m (0.20 kg-m, 1 ft-lb) Tighten bolts in numerical order as shown in the figure below. Torque Value: 5.88 N.m (0.60 kg-m, 4 ft-lb) Tighten bolts in numerical order as shown in the figure below. Torque Value: 10.4 N.m (1.1 kg-m, 8 ft-lb)
6. Measure difference in levels between front end faces of VVEL ladder assembly and cylinder head. Standard: -0.14 to 0.14 mm (-0.0055 to 0.0055 in) Measure two positions (both intake and exhaust side) for a single bank. If the measured value is out of the standard, re-install VVEL ladder assembly.
7. Install rear timing chain case. Refer to " «EXPLODED VIEW»(ref-616997-S15519648222014052000000) ".
8. Install camshaft sprockets and timing chains. Refer to " «EXPLODED VIEW»(ref-616997-S39914347982014052000000) ".
9. Install actuator bracket (rear) as follows: Apply a continuous bead of liquid gasket with tube presser (commercial service tool) to the actuator bracket (rear) as shown in the figure below. Use Genuine RTV Silicone Sealant or equivalent. Refer to " «RECOMMENDED CHEMICAL PRODUCTS AND SEALANTS»(ref-616989-S14994929602014052000000) ". CAUTION: Do not reuse O-rings. Never apply gasket to the oil passage. Tighten mounting bolts in the following steps, in numerical order as shown in the figure below. Tighten bolts in numerical order as shown in the figure below. Torque Value: 1.96 N.m (0.20 kg-m, 1 ft-lb) Tighten bolts in numerical order as shown in the figure below. Torque Value: 5.88 N.m (0.60 kg-m, 4 ft-lb) Tighten bolts in numerical order as shown in the figure below. Torque Value: 31.4 N.m (3.2 kg-m, 23 ft-lb)
10. Install new VVEL actuator sub assembly as follows: CAUTION: Regarding replacement, because VVEL actuator sub assembly and VVEL control shaft position sensor are controlled on a one-on-one basis, replace them as a set. NOTE: VVEL actuator arm (B) is factory-fixed at 5.5 degrees from the small lift with a holding jig (A). The holding jig is supplied in the new VVEL actuator sub assembly. CAUTION: Never disassemble VVEL actuator sub assembly. [Never loosen actuator motor mounting bolts (A) shown in the figure below] Never shock VVEL actuator sub assembly. Move control shaft to the position of small lift stopper. The position where a part of the stopper of control shaft contacts VVEL ladder bracket. CAUTION: Never damage the stopper surface. If control shaft cannot be moved, set crankshaft in position referring to the information below. (To displace cam nose) Bank 1: Turn 120 degrees from No. 1 cylinder at TDC Bank 2: No. 1 cylinder at TDC Hold two flat areas of control shaft with a wrench, and rotate the control shaft (5.5 degrees from the stopper) to the large lift side. (This is for aligning the bolt hole of control shaft and the hole of VVEL actuator arm.) Apply a continuous bead of liquid gasket with tube presser (commercial service tool) to the VVEL actuator sub assembly as shown in the figure below. Use Genuine RTV Silicone Sealant or equivalent. Refer to " «RECOMMENDED CHEMICAL PRODUCTS AND SEALANTS»(ref-616989-S14994929602014052000000) ". CAUTION: Never apply gasket to the oil passage. Install new VVEL actuator sub assembly. Tighten mounting bolts in the following step, in numerical order as shown below. CAUTION: When installing, be careful with VVEL actuator sub assembly (bank 2) mounting bolt No. 1 because its length is different. Be sure to check that the VVEL actuator sub assembly is in contact with the cylinder head before tightening the mounting bolts. Remove holding jig. Check that VVEL actuator arm bolt hole is aligned with control shaft tapped hole. If it is not aligned, turn control shaft for alignment. Fix two flat areas (C) of control shaft with a wrench to install mounting bolts of control shaft. CAUTION: During the operation, never allow a wrench to interfere with other parts. Fix control shaft to prevent the interference of the stopper surface.
11. Install new VVEL control shaft position sensor as follows: CAUTION: Regarding replacement, because VVEL actuator sub assembly and VVEL control shaft position sensor are controlled on a one-on-one basis, replace them as a set. Apply engine oil to O-ring or contact surface of O-ring. Align matching marks (B) of VVEL control shaft position sensor and upper housing. Face connector toward matching mark (A). Temporarily tighten bolt. Adjust VVEL control shaft position sensor after setting the engine assembly in the vehicle. Refer to " «VVEL CONTROL SHAFT POSITION SENSOR ADJUSTMENT: DESCRIPTION»(ref-616999-S35357146862014052000000) ". CAUTION: Be sure to adjust VVEL control shaft position sensor. After adjusting VVEL control shaft position sensor, tighten bolts to the specified torque.
12. Inspect the valve clearance. Refer to " «INSPECTION AND ADJUSTMENT»(ref-616997-S20972189582014052000000) ".
13. Install in the reverse order of removal after this step.

Scheme 193

1. Put V-block on precise flat table, and support No. 2 and 4 journals of camshaft. CAUTION: Never support No. 1 journal (on the side of camshaft sprocket) because it has a different diameter from the other three locations.
2. Set a dial indicator vertically to No. 3 journal.
3. Turn camshaft (EXH) to one direction with hands, and measure the camshaft runout on a dial indicator. (Total indicator reading) Standard and limit: Refer to " «CAMSHAFT»(ref-616997-S37058832272014052000000) ".
4. If it exceeds the limit, replace camshaft (EXH).

Scheme 194

1. Measure the camshaft (EXH) cam height with a micrometer. Standard: Refer to " «CAMSHAFT»(ref-616997-S37058832272014052000000) ".
2. If wear exceeds the limit, replace camshaft (EXH).

VVEL Ladder Assembly

DRIVE SHAFT OPERATIONAL CHECK

Scheme 195

1. Hold the both ends of the drive shaft (A) and rotate it to check that it rotates smoothly. CAUTION: Turn VVEL ladder assembly upside down to prevent the drive shaft from dropping off.

CONTROL SHAFT OPERATIONAL CHECK

Scheme 196

1. Move control shaft (A) to the small stopper and large stopper to check that the control shaft functions smoothly. CAUTION: Turn VVEL ladder assembly upside down to prevent the drive shaft from dropping off.

LINK CHECK FOR BACK-LASH (BONDING)

Scheme 197

1. Check that the link and the shaft of drive shaft and control shaft are not fixed.
2. Check this by moving drive shaft and control shaft in the axial and rotation directions.
3. If there is an unusualness related to the above three, replace VVEL ladder assembly and cylinder head assembly.

Note. VVEL ladder assembly cannot be replaced as a single part, because it is machined together with cylinder head assembly.

Scheme 198

Scheme 199

Scheme 200

Scheme 201

Scheme 202

Scheme 203

Scheme 204

Scheme 205

Scheme 206

Scheme 207

Scheme 208

Scheme 209

Scheme 210

Scheme 211

Scheme 212

Scheme 213

Scheme 214

Scheme 215

Scheme 216

Scheme 217

1. Fully air-blow engine coolant and engine oil passages in cylinder block, cylinder bore and crankcase to remove any foreign material. CAUTION: Use goggles to protect your eyes.
2. Install each plug to cylinder block as shown in the figure below. Apply sealant to the thread of water drain plug (1). Use Genuine RTV Silicone Sealant or equivalent. Refer to " «RECOMMENDED CHEMICAL PRODUCTS AND SEALANTS»(ref-616989-S14994929602014052000000) ". Apply sealant to the thread of plug (4). Use Genuine High Strength Thread Locking Sealant or equivalent. Refer to " «RECOMMENDED CHEMICAL PRODUCTS AND SEALANTS»(ref-616989-S14994929602014052000000) ". Replace washers (2) with new ones. CAUTION: Do not reuse washers. Tighten each plug as specified below. Unit: N.m (kg-m, ft-lb) Part Washer Tightening torque 1 No 19.6 (2.0, 14) 3 Yes 78.0 (8.0, 58) 4 Yes 12.3 (1.3, 9)
3. Install oil jet. Insert oil jet dowel pin (A) into cylinder block dowel pin hole, and tighten mounting bolts.
4. Install main bearings and thrust bearings as follows: CAUTION: Never drop main bearing, and to scratch the surface. Remove dust, dirt, and engine oil on bearing mating surfaces of cylinder block and lower cylinder block. Install thrust bearings (1) to both sides of the No. 3 journal housing on cylinder block. Install thrust bearings with the oil groove (E) facing crankshaft arm (outside). Install main bearings paying attention to the direction. Main bearing with oil hole (B) and groove (C) goes on cylinder block. The one without them goes on lower cylinder block. Before installing main bearings, apply engine oil to the bearing surface (inside). Do not apply engine oil to the back surface, but thoroughly clean it. When installing, align main bearing stopper protrusion to cutout of cylinder block and lower cylinder block. Ensure the oil holes on cylinder block and those on the corresponding bearing are aligned.
5. Install crankshaft to cylinder block. While turning crankshaft by hand, check that it turns smoothly.
6. Install lower cylinder block. NOTE: Lower cylinder block cannot be replaced as a single part, because it is machined together with cylinder block. Apply a continuous bead of liquid gasket with the tube presser (commercial service tool) to lower cylinder block as shown in the figure below. Use Genuine RTV Silicone Sealant or equivalent. Refer to " «RECOMMENDED CHEMICAL PRODUCTS AND SEALANTS»(ref-616989-S14994929602014052000000) ".
7. Inspect the outer diameter of lower cylinder block bolt. Refer to " «INSPECTION»(ref-616997-S33990223162014052000000) ".
8. Install lower cylinder block bolts in numerical order as shown in the figure below, as follows: Apply new engine oil to threads and seat surfaces of lower cylinder block bolts. Tighten bolts (No. 17 to 26) in numerical order as shown in the figure below. Torque Value: 25.0 N.m (2.6 kg-m, 18 ft-lb) Repeat step b . Tighten bolts (No. 1 to 16) in numerical order as shown in the figure below. NOTE: Use TORX socket for bolts No. 1 to 16. Torque Value: 35.3 N.m (3.6 kg-m, 26 ft-lb) Turn bolts (No. 1 to 16) 90 degrees clockwise (angle tightening). CAUTION: Use the angle wrench [SST: KV10112100 (BT8653-A)] (A) to check tightening angle. Never make judgment by visual inspection. After installing lower cylinder block bolts, check that crankshaft can be rotated smoothly by hand. Check the crankshaft end play. Refer to " «INSPECTION»(ref-616997-S33990223162014052000000) ".
9. Install piston to connecting rod as follows: Using snap ring pliers, install new snap ring to the groove of piston rear side. Insert it fully into groove to install. Install piston to connecting rod. Using an industrial use dryer or similar tool, heat piston until piston pin can be pushed in by hand without excess force [approximately 60 to 70°C (140 to 158°F)]. From the front to the rear, insert piston pin into piston and connecting rod. Assemble so that the front mark on the piston head and the cylinder number on connecting rod are positioned as shown in the figure below. Install new snap ring to the groove of the piston front side. Insert it fully into groove to install. After installing, check that connecting rod moves smoothly.
10. Using a piston ring expander (commercial service tool) (A), install piston rings. CAUTION: When installing piston rings, be careful not to damage piston. Never damage piston rings by expending them excessively. If there is stamped mark on ring, mount it with marked side up. Stamped mark: Top ring (A): 1 N Second ring (B): 2 N Position each ring with the gap as shown in the figure below, referring to the piston front mark (D). Check the piston ring side clearance. Refer to " «INSPECTION»(ref-616997-S33990223162014052000000) ".
11. Install connecting rod bearings to connecting rod and connecting rod bearing cap. CAUTION: Never drop connecting rod bearing, and to scratch the surface. Before installing connecting rod bearings, apply engine oil to the bearing surface (inside). Do not apply engine oil to the back surface, but thoroughly clean it. When installing, align connecting rod bearing stopper protrusion (B) with cutout (C) of connecting rods and connecting rod bearing caps to install. Ensure the oil hole (A) on connecting rod and that on the corresponding bearing are aligned.
12. Install piston and connecting rod assembly to crankshaft. Position crankshaft pin corresponding to connecting rod to be installed onto the bottom dead center. Apply engine oil sufficiently to the cylinder bore, piston and crankshaft pin journal. Match the cylinder position with the cylinder number on connecting rod to install. Be sure that front mark on piston crown is facing the front of the engine. Using a piston ring compressor [SST: EM03470000 (J-8037)] (A) or suitable tool, install piston with the front mark on the piston crown facing the front of the engine. CAUTION: Never damage the cylinder wall and crankshaft pin, resulting from an interference of the connecting rod big end.
13. Install connecting rod bearing cap. Match the stamped cylinder number marks on connecting rod with those on connecting rod bearing cap to install. Be sure that front mark (H) on connecting rod bearing cap is facing the front of the engine.
14. Tighten connecting rod bolt as follows: Inspect the outer diameter of connecting rod bolt. Refer to " «INSPECTION»(ref-616997-S33990223162014052000000) ". Apply engine oil to the threads and seats of connecting rod bolts. Tighten connecting rod bolts. Torque Value: 28.4 N.m (2.9 kg-m, 21 ft-lb) Completely loosen connecting rod bolts. Torque Value: 0 N.m (0 kg-m, 0 ft-lb) Tighten connecting rod bolts. Torque Value: 24.5 N.m (2.5 kg-m, 18 ft-lb) Then turn connecting rod bolts 90 degrees clockwise (angle tightening). CAUTION: Always use the angle wrench [SST: KV10112100 (BT8653-A)] (A). Never make judgment by visual inspection. After tightening connecting rod bolts, check that crankshaft rotates smoothly. Check the connecting rod side clearance. Refer to " «INSPECTION»(ref-616997-S33990223162014052000000) ".
15. Install baffle plate.
16. Install new rear oil seal. Refer to " «REAR OIL SEAL: REMOVAL AND INSTALLATION»(ref-616997-S35740330932014052000000) ". Apply new engine oil to both oil seal lip and dust seal lip.
17. Install pilot converter. With a drift of the following outer diameter, press-fit as far as it will go. Pilot converter: Approx. 33 mm (1.30 in) Press-fit pilot converter with its chamfer facing crankshaft as shown in the figure below.
18. Install knock sensors. Install knock sensor so that connector faces the rear of the engine. After installing knock sensor, connect harness connector, and lay it out to rear of the engine. CAUTION: Never tighten mounting bolts while holding connector. If any impact by dropping is applied to knock sensor, replace it with new one. NOTE: Check that there is no foreign material on the cylinder block mating surface and the back surface of knock sensor. Check that knock sensor does not interfere with other parts.
19. Note the following, assemble in the reverse order of disassembly after this step. Drive plate When installing drive plate to crankshaft, be sure to correctly align crankshaft side dowel pin and drive plate side dowel pin hole. CAUTION: If these are not aligned correctly, engine runs roughly and "MIL" illuminates. Install drive plate (2) and reinforcement plate (3) as shown in the figure below. Holding ring gear with the ring gear stopper [SST: KV10118600 (J-48641)]. Tighten the mounting bolts crosswise over several times.

Scheme 218

1. Measure the clearance between thrust bearings and crankshaft arm when crankshaft is moved fully forward or backward with a dial indicator. Standard and limit: Refer to " «CYLINDER BLOCK»(ref-616997-S40028841062014052000000) ".
2. If the measured value exceeds the limit, replace thrust bearings, and measure again. If it still exceeds the limit, replace crankshaft also.

Scheme 219

1. Measure the side clearance between connecting rod and crankshaft arm with a feeler gauge. Standard and limit: Refer to " «CYLINDER BLOCK»(ref-616997-S40028841062014052000000) ".
2. If the measured value exceeds the limit, replace connecting rod, and measure again. If it still exceeds the limit, replace crankshaft also.