Valve Clearance: Adjustments

Valve Arrangement

FRONT TO REAR

Right .......I-E-I-E-I-E-I-E
Left .......E-I-E-I-E-I-E-I

Fig. 5 Positioning crankshaft for valve clearance check.:

Fig. 6 Checking collapsed tappet clearance:

Valves, Adjust
For these engines, a .060 inch longer or a .060 inch shorter pushrod is available to provide a means of compensating for dimensional changes in the valve train and rocker arm. If the clearance is less than the minimum, the .060 inch shorter pushrod should be used. If clearance is more than the maximum the .060 inch longer pushrod should be used.
Valve stem to valve rocker arm clearance should be within specification with the hydraulic tappet completely collapsed. Repeated valve reconditioning operations (valve and/or valve seat refacing) will decrease the clearance to the point that if it is not compensated for, the hydraulic valve tappet will cease to function and the valve will be held closed.
To check valve clearance, proceed as follows:
1. Mark crankshaft pulley at three locations with number 1 location at TDC timing mark (end of compression stroke), number 2 location one half turn (180°) clockwise from TDC and number 3 location three quarter turn clockwise (270°) from TDC, Fig. 5.
2. Turn the crankshaft to the number 1 location, then compress valve lifter using tool T71P-6513-A or equivalent, Fig. 6, and check the clearance on the following valves: V8-255, 302 Except H.O.; No. 1 Intake, No. 1 Exhaust, No. 7 Intake, No. 5 Exhaust, No. 8 Intake, No. 4 Exhaust: V8-302 H.O. & 351; No. 1 Intake, No. 1 Exhaust, No. 4 Intake, No. 3 Exhaust, No. 8 Intake, No. 7 Exhaust.
3. Turn the crankshaft to the number 2 location, then compress valve lifter using tool T71P-6513-A or equivalent, and check the clearance on the following valves: V8-255, 302 Except H.O.; No. 5 Intake, No. 2 Exhaust, No.4 Intake, No. 6 Exhaust: V8-302 H.O. & 351; No. 3 Intake, No. 2 Exhaust, No. 7 Intake No. 6 Exhaust.
4. Turn the crankshaft to the number 3 location, then compress valve lifter using tool T71P-6513-A or equivalent, and check the clearance on the following valves: V8-255, 302 Except H.O.; No. 2 Intake, No. 7 Exhaust, No. 3 Intake, No. 3 Exhaust, No. 6 Intake, No. 8 Exhaust: V8-302 H.O. & 351; No. 2 Intake, No. 4 Exhaust, No. 5 Intake, No. 5 Exhaust, No. 6 Intake, No. 8 Exhaust.
Adjust valve lash. On 1982 V8-255 & 1982 - 88 V8-302, valve clearance should be .096 - .146; On 1983 - 88 V8-302 HO, valve clearance should be .123 - .146. On 1982 V8-351, valve clearence should be .096 - .146.