Engine Mechanical: Adjustments Infiniti QX80 I

Tension Adjustment

Refer to " DRIVE BELTS ".

Scheme 8

1. Move reservoir tank to the position without the hindrance for work. Refer to " «EXPLODED VIEW»(ref-618041-S30452018462014052700000) ".
2. Install wrench (A) on drive belt auto tensioner pulley bolt, move in the direction of arrow (loosening direction of tensioner) as shown below. CAUTION: Never place hand in a location where pinching may occur if the holding tool accidentally comes off. Never loosen the hexagonal part in center of auto tensioner pulley (1) (Never turn it clockwise). If turned clockwise, the complete auto tensioner must be replaced as a unit, including the pulley.
3. Under the above condition, insert a metallic bar (B) of approximately 6 mm (0.24 in) in diameter (hexagonal bar wrench shown as example in the figure above) through the holding boss to lock auto tensioner pulley arm.
4. Remove drive belt.

EXHAUST CAMSHAFT VALVE CLEARANCE ADJUSTMENT

1. Perform adjustment depending on selected head thickness of valve lifter (EXH).

Scheme 9

Scheme 10

1. Measure the valve clearance. Refer to " «INSPECTION»(ref-618039-S00982613672014052700000) ".
2. Remove VVEL ladder assembly and exhaust camshaft. Refer to " «REMOVAL AND INSTALLATION»(ref-618039-S26605386692014052700000) ". CAUTION: Never loosen adjusting bolts and mounting bolts (black color) of VVEL ladder assembly.
3. Remove valve lifter (EXH) at the locations that are out of the standard.
4. Measure the center thickness of the removed valve lifters (EXH) with a micrometer (A).
5. Use the equation below to calculate valve lifter (EXH) thickness for replacement. Valve lifter (EXH) thickness calculation: t = t1+ (C1 - C2) t = Valve lifter (EXH) thickness to be replaced t1 = Removed valve lifter (EXH) thickness C1 = Measured valve clearance C2 = Standard valve clearance: Exhaust: 0.33 mm (0.013 in) Thickness of new valve lifter (EXH) can be identified by stamp marks on the reverse side (inside the cylinder). Stamp mark 788 indicates 7.88 mm (0.3102 in) in thickness. Available thickness of valve lifter (EXH): 27 sizes with range 7.88 to 8.40 mm (0.3102 to 0.3307 in) in steps of 0.02 mm (0.0008 in) (when manufactured at factory). Refer to " «CAMSHAFT»(ref-618039-S16540701132014052700000) ".
6. Install selected valve lifter (EXH).
7. Install VVEL ladder assembly and exhaust camshaft. Refer to " «REMOVAL AND INSTALLATION»(ref-618039-S26605386692014052700000) ".
8. Manually turn crankshaft pulley a few turns.
9. Check that the valve clearances for cold engine are within the specifications by referring to the specified values. Refer to " «INSPECTION»(ref-618039-S00982613672014052700000) ".
10. Install all removed parts in the reverse order of removal.
11. Warm up the engine, and check for unusual noise and vibration.

Scheme 11

1. Put V-block on precise flat table, and support No. 2 and 5 journals of camshaft. CAUTION: Never support No. 1 journal (on the side of camshaft sprocket) because it has a different diameter from the other four locations.
2. Set a dial indicator vertically to No. 3 journal.
3. Turn exhaust camshaft to one direction with hands, and measure the camshaft runout on a dial indicator. (Total indicator reading) Standard and limit : Refer to " «CAMSHAFT»(ref-618039-S16540701132014052700000) ".
4. If it exceeds the limit, replace exhaust camshaft.

Scheme 12

1. Measure the exhaust camshaft cam height with a micrometer. Standard and limit : Refer to " «CAMSHAFT»(ref-618039-S16540701132014052700000) ".
2. If wear exceeds the limit, replace exhaust camshaft.