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Camshaft: Diagnosis Lexus LS II

Mechanical 5 illustrations ~1145 words

Inspection

  1. Inspect components for damage. Check camshaft journal diameter, lobe height and journal runout. Replace camshaft if not within specification. See «CAMSHAFT»(ref-49513-S13257640302001011500000) under ENGINE SPECIFICATIONS.
  2. To check journal clearance, install camshafts in cylinder head one at a time without lifters. Using Plastigage, check camshaft oil clearance. Tighten camshaft bearing cap bolts to specification in sequence. DO NOT turn camshaft. (Scheme 31) See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000).
  3. Remove camshaft and check clearance. Replace camshaft and/or cylinder head if oil clearance is not within specification. See «CAMSHAFT»(ref-49513-S13257640302001011500000) under ENGINE SPECIFICATIONS.
  4. Check camshaft end play with camshaft bearing cap bolts tightened to specification. Replace camshaft and/or cylinder head if end play is not within specification. See «CAMSHAFT»(ref-49513-S13257640302001011500000) under ENGINE SPECIFICATIONS.
  5. Install both camshafts in cylinder head without sub-gear installed on exhaust camshaft. Tighten camshaft bearing cap bolts to specification in sequence. (Scheme 31) See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). Check gear backlash between camshaft gears.
  6. Replace camshafts if gear backlash exceeds specification. See «CAMSHAFT»(ref-49513-S13257640302001011500000) under ENGINE SPECIFICATIONS. Measure distance between ends of gear spring. Replace gear spring if distance is not 0.716-0.740" (18.2-18.8 mm).

Scheme 29

Scheme 29: Installation
Scheme 29: Installation

Scheme 30

Scheme 30
Scheme 30
  1. Install NEW circular plugs in camshaft bore in rear of cylinder head. Ensure cup side faces inward. Apply sealant on rear intake camshaft bearing cap-to-cylinder head surface.
  2. On right cylinder head, install intake camshaft bearing cap I1, with arrow on top of bearing cap facing rearward, toward rear of engine. (Scheme 29) On left cylinder head, install intake camshaft bearing cap I6, with arrow on top of bearing cap facing forward, toward timing belt end of engine.
  3. Install NEW seal washer on Silver colored camshaft bearing cap bolts for rear intake camshaft bearing caps. Lubricate bolt threads with engine oil. Install bolts in rear camshaft bearing caps and tighten to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). NOTE: Rear camshaft bearing cap bolts are Silver colored.
  4. To reassemble exhaust camshaft, install gear spring, sub-gear, wave washer and snap ring. Hook spring ends to pins on camshaft main gear and sub-gear. Using Spanner (09960-10010), rotate sub-gear clockwise and install service bolt. Ensure teeth on main gear and sub-gear are aligned before tightening service bolt.
  5. To install right cylinder head camshafts, apply grease to thrust surfaces of intake camshaft. Install intake camshaft in right cylinder head. Position intake camshaft with timing mark (one dot) at 45-degree angle to cylinder head. see scheme 26
  6. Apply sealant on surface between intake camshaft bearing cap I6 and cylinder head. Install camshaft bearing caps on intake camshaft with arrows pointing rearward, in same direction as arrow on cylinder head. see scheme 25
  7. Coat threads of camshaft bearing cap bolts with engine oil. Coat contact surfaces between camshaft bearing caps and bolt heads of bolts "A" with engine oil. (Scheme 30) Ensure NEW seal washer is installed on bolts "B". Install proper length bolts in specified area. (Scheme 30)
  8. Tighten intake camshaft bearing cap bolts to specification in sequence using several steps. (Scheme 31) See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). Rotate intake camshaft so timing mark (one dot) is at 10-degree angle to cylinder head.
  9. Apply grease to thrust surfaces of exhaust camshaft for right cylinder head. Align timing mark (one dot) on camshaft gears. Install exhaust camshaft in right cylinder head. (Scheme 32) Ensure exhaust camshaft moves smoothly back and forth.
  10. Install camshaft bearing caps on exhaust camshaft with arrows pointing rearward, in same direction as arrow on cylinder head. see scheme 24
  11. Coat threads and camshaft bearing cap-to-bolt head surface with engine oil. Install oil pipe and camshaft bearing cap bolts. Install proper length bolts in specified area. (Scheme 30)
  12. Tighten exhaust camshaft bearing cap bolts to specification in sequence using several steps. (Scheme 31) Alternately tighten oil pipe bolts at intake camshaft bearing cap bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). Remove service bolt from exhaust camshaft.
  13. To install left cylinder head camshafts, apply grease to thrust surfaces of intake camshaft. Install intake camshaft in left cylinder head. Position intake camshaft with timing mark (one dot) at 60-degree angle to cylinder head. see scheme 26
  14. Apply sealant on surface between intake camshaft bearing cap I1 and cylinder head. Install camshaft bearing caps on intake camshaft with arrows pointing forward, in same direction as arrow on cylinder head. see scheme 25
  15. Coat threads of camshaft bearing cap bolts with engine oil. Coat contact surfaces between camshaft bearing caps and bolt heads of bolts "A" with engine oil. (Scheme 30) Ensure NEW seal washer is installed on bolts "B". Install proper length bolts in specified area.
  16. Tighten intake camshaft bearing cap bolts to specification in sequence using several steps. (Scheme 31) See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). Rotate intake camshaft so timing mark (2 dots) is at 15-degree angle to cylinder head.
  17. Apply grease to thrust surfaces of exhaust camshaft for left cylinder head. Align timing mark (2 dots) on camshaft gears, and install exhaust camshaft in left cylinder head. (Scheme 32) Ensure exhaust camshaft moves smoothly back and forth.
  18. Install camshaft bearing caps on exhaust camshaft with arrows pointing forward, in the same direction as arrow on cylinder head. see scheme 24
  19. Coat threads and camshaft bearing cap-to-bolt head surface with engine oil. Install oil pipe and camshaft bearing cap bolts. Install proper length bolts in specified area. (Scheme 30)
  20. Tighten exhaust camshaft bearing cap bolts to specification in sequence using several steps. (Scheme 31) Alternately tighten oil pipe bolts at intake camshaft bearing cap bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). Remove service bolt "B" from exhaust camshaft.
  21. Coat lip of NEW oil seal with grease. Install oil seal onto intake camshaft. Using hammer and Oil Seal Installer (SST 09223-46011), tap oil seal into camshaft bearing cap.
  22. Check and adjust valve clearance. See «VALVE CLEARANCE ADJUSTMENT»(ref-49513-S12958173942001011500000) under ADJUSTMENTS. Install timing belt rear plates. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). Install camshaft sprockets and timing belt. Apply sealant on groove of 4 half-circular plugs and install in cylinder heads. see scheme 12 NOTE: There are 2 half-circular plugs for each cylinder head. Ensure both half-circular plugs are installed in each cylinder head.
  23. Apply sealant at valve cover sealing areas on front of cylinder head. see scheme 5 Install valve covers using NEW gaskets. Install seal washer and bolts. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000).
  24. To install remaining components, reverse removal procedure. Fill and bleed cooling system. See «COOLING SYSTEM BLEEDING»(ref-49513-S07553328822001011500000).

Scheme 31

Scheme 31
Scheme 31

Scheme 32

Scheme 32
Scheme 32

HINT: The thermostat is numbered with the valve opening temperature.

Scheme 33

Scheme 33: Inspection
Scheme 33: Inspection
  1. Immerse the thermostat in water and gradually heat the water.
  2. Check the valve opening temperature. Valve opening temperature: 80-84° C (176-183° F) If the valve opening temperature is not as specified, replace the thermostat.
  3. Check the valve lift. Valve lift: 10 mm (0.39 in) or more at 95° C (203° F) If the valve lift is not as specified, replace the thermostat.
  4. Check that the valve spring is tight when the thermostat is fully closed. If not closed, replace the thermostat

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