The intake and exhaust valves are driven by the camshaft, working through hydraulic lash adjusters and stamped steel rocker arms. The lash adjusters eliminate the need for periodic valve lash adjustments.Diesel Engines
See Figures 1, 2, 3 and 4
- Disconnect the breather hose from the intake manifold and remove the camshaft cover.
- Rotate crankshaft until No. 1 piston is at Top Dead Center (TDC) on the compression stroke.
- Using a wire feeler gauge, check the valve shim to cam lobe clearance for No. 1 and No. 2 intake valves, and No. 1 and No. 3 exhaust valves.
The valve adjustment specifications are as follows:
- Rotate the crankshaft one complete revolution. Measure valve clearance for No. 3 and No. 4 intake valves, and No. 2 and No. 4 exhaust valves.
If a valve is out of specifications, adjust as follows:
- Rotate the crankshaft until the lobe of the valve to be adjusted is down.
- Install the cam follower retainer, T84P-6513-B.
- Rotate the crankshaft until the cam lobe is on the base circle.
- Using a O-ring pick tool T71P-19703-C or equivalent, pry the valve adjusting shim out of the cam follower.Valve shims are available in thicknesses ranging from 0.13-0.18 in. (3.40-4.60mm).
- If the valve was too tight, install a new shim, of the appropriate size.
- If the valve was too loose, install a new shim of the appropriate size.Shim thickness is stamped on the valve shim. Install the new shim with the numbers facing down, to avoid wearing the numbers off the shim. If the numbers have been worn off, use a micrometer to measure shim thickness.
- Rotate the crankshaft until the cam lobe is down and remove the cam follower retainer.
- Recheck the valve clearance.
- Repeat Steps 4, 5 and 6 for each valve to be adjusted.
- Make sure the camshaft cover gasket is fully seated in the camshaft cover and install the valve cover. Tighten the bolts to 5-7 ft. lbs. (7-9 Nm).
- Connect the breather hose.