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INSPECTION

Runout
  1. Place the camshaft on V-blocks.
  2. Using a dial indicator, measure the circle runout at the center journal. Maximum circle runout is 0.0024 inch (0.06mm). If the runout is greater than maximum, replace the camshaft.

    Fig. 1: Use a dial indicator to measure circle runout of the camshaft

Lobe Height
  1. Using a micrometer, measure the cam lobe height. Standard cam lobe height:
  2. If the cam lobe height is less than minimum, replace the camshaft.

    Fig. 2: Place a micrometer over the cam lobe and measure the height, if less than minimum, replace the camshaft

Journals
  1. Using a micrometer, measure the journal diameter. Standard diameter is 1.0614–1.0620 inch (26.959–26.975mm). If the diameter is not as specified, check the oil clearance.

    Fig. 3: Use a micrometer to measure the journal diameter of the camshaft

Bearings

Check the bearings for flaking and scoring. If the bearings seem to be damaged, replace the caps and cylinder head as a set.

Fig. 4: Check the bearings for flaking and scoring

Journal Oil Clearance
  1. Clean the bearing caps and camshaft journals.
  2. Place the camshafts on the cylinder head.
  3. Lay a strip of Plastigageacross each camshaft journal.
  4. Install the bearing caps and tighten to 12 ft. lbs. (15 Nm). Do not turn the camshaft.
  5. Remove the bearing caps.
  6. Measure the Plastigageat its widest point. Standard oil clearance is 0.0010–0.0024 inch (0.025–0.062mm). Maximum oil clearance is 0.0031 inch (0.08mm). If the oil clearance is greater than maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
  7. Completerly remove the gauge material.

    Fig. 5: Place the gauging material across the camshaft journals . . .

    Fig. 6: . . . then measure it at its widest point

Thrust Clearance
  1. install the camshaft.
  2. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
  3. If the thrust clearance is greater than maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.

    Fig. 7: Place a dial indicator at the end of the camshaft as shown and measure the thrust clearance

Camshaft Gear Backlash
  1. Install the camshafts without installing the exhaust cam sub-gear.
  2. Using a dial indicator, measure the gear backlash.
  3. If the backlash is greater than maximum, replace the camshafts.

    Fig. 8: Place a dial indicator on the camshaft gear and measure the gear backlash

Camshaft Gear Spring

Using a venire caliper, measure the free distance between the spring ends. The distance should be between 0.886–0.902 inch (22.5–22.9mm). If the free distance is not as specified, replace the gear spring.

Fig. 9: The free distance is measure in between the two spring ends

Valve Lifters and Lifter Bores
  1. Using a caliper gage, measure the lifter bore diameter of the cylinder head. Standard lifter bore diameter is 1.2205–1.2211 inch (31.000–31.016mm).

    Fig. 10: Insert a caliper gage into the lifter bore and measure the diameter

  2. Using a micrometer, measure the lifter diameter. Standard diameter is 1.2191–1.2195 inch 930.966–30.976mm).

    Fig. 11: A micrometer will measure the outside lifter diameter

  3. Subtract the lifter diameter measurement from the lifter bore diameter measurement.
  4. If the oil clearance is greater than maximum, replace the lifter. If necessary, replace the cylinder head.

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