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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis (Single Page) >> Engine Mechanical >> Mechanical >> 7.4L V8 - VIN [N] >> Adjustments >> Valve Clearance Adjustment

Valve Clearance Adjustment

NOTE: Although valve clearance adjustment is not usually required (engine uses hydraulic valve lifters), perform the following procedures after servicing valve train.
  1. Rotate engine until No. 1 piston is on TDC of compression stroke. Go to step 2) and adjust specified valves as listed in VALVE CLEARANCE ADJUSTMENT table.
  2. Loosen rocker arm adjusting nut until lash is present. Tighten adjusting nut until lash is removed (under this condition, push rod cannot be rotated with fingers). Tighten adjusting nut 3/4 turn.
  3. Rotate crankshaft 360 degrees to bring No. 6 piston to TDC of compression stroke. Adjust remaining valves. See VALVE CLEARANCE ADJUSTMENT table
VALVE CLEARANCE ADJUSTMENT

Piston at TDC Adjust Intake Adjust Exhaust
No. 1 No. 1, 2, 5 & 7 No. 1, 3, 4 & 8
No. 6 No. 3, 4, 6 & 8 No. 2, 5, 6 & 7
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