See Figure 6
Fig. 6: Hydraulic valve clearance adjustment-4.9L engine
Rotate the crankshaft by hand so that No. 1 piston is at TDC of the compression stroke. Make a chalk mark on the damper at that point, then, make 2 more chalk marks about 120° apart, dividing the damper into 3 equal parts.
With No. 1 at TDC, tighten the rocker arm bolts on No. 1 cylinder intake and exhaust to 17-23 ft. lbs. (23-31 Nm). Then, slowly apply pressure, using Lifter Bleed-down wrench T70P-6513-A, or equivalent, to completely bottom the lifter. Take care to avoid excessive pressure that might bend the pushrod. Hold the lifter in this position and check the clearance between the rocker arm and the valve stem tip. Allowable clearance is 2.5-5.0mm (0.10-0.20 in.) with a desired clearance of 3.0-4.5mm (0.125-0.175 in.).
If the clearance is less than specified, install a shorter pushrod. If the clearance is greater than specified, install a longer pushrod.
Rotate the crankshaft clockwise (as viewed from the front) until the next chalk mark is aligned with the timing pointer. Repeat the procedure for No. 5 intake and exhaust.
Rotate the crankshaft to the next chalk mark and repeat the procedure for No. 3 intake and exhaust.
Repeat the rotation/checking procedure for the remaining valves in firing order, that is: 6-2-4.