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Home >> Jaguar >> 1989 >> XJ6 Base >> Repair and Diagnosis >> Engine Performance >> Engine Controls - Adjustments >> Engine Mechanical >> Valve Clearance

Valve Clearance

  1. Adjust valves with engine cold. With camshaft cover removed, rotate camshafts and record clearance between heel of each cam lobe and its respective tappet. If adjustment is necessary, rotate camshaft and align with Timing Gauge (18G 1433).
    CAUTION: DO NOT  rotate engine while the camshaft sprocket is disconnected from camshaft. Serious damage can occur to valve train components.
  2. Note rotor and distributor position. Remove distributor from engine. Loosen one chain tensioner bolt and swing clamp away from center of chain tensioner. See Fig 1 .
    Fig 1: Camshaft Chain Tensioner (XJ6)
    G93115Courtesy of JAGUAR CARS, INC.
  3. Remove valve from center of tensioner. Insert a 3 mm Allen key into center of tensioner. Turn Allen key clockwise until a click is heard. Chain tension is relieved.
  4. Remove chain tensioner bolts. Remove chain tensioner. Discard "O" ring and gasket from chain tensioner. Remove camshaft sprocket bolts. Remove camshaft sprockets.
  5. Remove camshaft bearing caps one at a time, starting from center. Install Spacer (18G 1435) to cylinder head. Tighten spacer with cylinder head bolt. Tighten cylinder head bolt to 45 ft. lbs. (61 N.m), then turn bolt an additional 90 degrees.
  6. Repeat step 5) until all camshaft caps are removed and replaced with spacers. Remove camshaft. Remove each tappet that required adjustment, and note its location for reassembly in its original position. Remove adjusting pad and measure thickness.
  7. Use measured pad thickness and difference between measured valve clearance and specified clearance to calculate required thickness of new adjusting pad. Adjusting pads are available in increments of .001" (.03 mm) from .085" (2.16 mm) to .108" (2.74 mm) and are marked with letters from "A" to "X" respectively.
  8. Insert correct adjusting pads and install cam followers. Install camshafts and align with timing gauge. Remove spacers from cylinder head in the following order: No. 1, 4, 2, 3, 5, and 6 cylinders. After removing one spacer, immediately install camshaft bearing cap before removing remaining spacers.
    NOTE: Always use new cylinder head bolts when installing bearing caps.
  9. Install camshaft bearing caps. Tighten new cylinder head bolts in sequence to 45 ft. lbs. (61 N.m), then turn bolt an additional 90 degrees. See Fig 2 . Install camshaft bearing cap bolts. Tighten camshaft bolts to 17-20 ft. lbs. (23-27 N.m).
    Fig 2: Cylinder Head Tightening Sequence (XJ6)
    G90J15569Courtesy of JAGUAR CARS, INC.
  10. Install camshaft sprocket. Tighten camshaft sprocket nuts to 17-20 ft. lbs. (23-27 N.m). Install cam timing chain, chain tensioner and camshaft covers. Tighten camshaft cover bolts to 13.3 INCH lbs. (1.5 N.m).
XJ6 VALVE CLEARANCE SPECIFICATIONS

Application In. (mm)
Intake & Exhaust .012-.014 (.30-.36)
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