Valve Lash Adjustment And Verification
| 1 - INTAKE |
| 2 - FEELER GAUGE |
| 3 - EXHAUST |
To obtain accurate readings, valve lash measurements and adjustments should only be performed when the engine coolant temperature is less than 60° C (140° F.).
The 24-valve overhead system is a "low-maintenance" design. Routine adjustments are no longer necessary, however, measurement should still take place when troubleshooting performance problems, or upon completion of a repair that includes removal and installation of the valve train components or injectors.
- Disconnect battery negative cables.
- Remove cylinder head cover. Refer to COVER(S), Cylinder Head, Removal, 6.7L .
- Using the barring tool (special tool #7471B, Barring Tool), rotate crankshaft to align damper TDC mark to 12:00 o'clock position.
- If both number one cylinder rocker levers are loose, continue to next step.
- If both number one cylinder rocker levers are not loose, rotate crankshaft 360°.
- With the engine in this position, valve lash can be measured at the following rocker arms: INTAKE 1-2-4 / EXHAUST 1-3-5.
Measure the valve lash by inserting a feeler gauge between the rocker arm socket and crosshead. Refer to VALVE LASH LIMIT CHART for the correct specifications. If the measurement falls within the limits, adjustment/resetting is not necessary. If measurement finds the lash outside of the limits, adjustment/resetting is required.VALVE LASH LIMIT CHART
INTAKE EXHAUST 0.152 mm (0.006 in.) MIN. 0.533 mm (0.021 in.) MIN. 0.381 mm (0.015 in.) MAX. 0.863 mm (0.034 in.) MAX. NOTE:If measured valve lash falls within these specifications, no adjustment/reset is necessary. Engine operation within these ranges has no adverse affect on performance, emissions, fuel economy or level of engine noise.
1 - INTAKE 2 - FEELER GAUGE 3 - EXHAUST - If adjustment/resetting is required, loosen the lock nut on rocker arms and turn the adjusting screw until the desired lash is obtained:
- INTAKE 0.254 mm (0.010 in.)
- EXHAUST 0.660 mm (0.026 in.)
Tighten the lock nut to 24 N.m (18 ft. lbs.) and recheck the valve lash.
- Using the crankshaft barring tool, rotate the crankshaft one revolution (360°) to align the damper TDC mark to the 12 o'clock position.
- With the engine in this position, valve lash can be measured at the remaining rocker arms: INTAKE 3-5-6 / EXHAUST 2-4-6 . Use the same method as above for determining whether adjustment is necessary, and adjust those that are found to be outside of the limits.
- Install the cylinder head cover. Refer to COVER(S), Cylinder Head, Installation, 6.7L .
- Connect the battery negative cables.