Bronco L6-300 4.9L VIN Y 1-bbl (1983)
Valve Clearance: Adjustments
Valves, Adjust
1.
Crank engine with ignition Off, using an auxiliary starter switch.
2.
Mark crankshaft damper at two locations, approximately 120° apart, so that, with the timing mark, the damper is divided into three equal sections.
3.
Rotate crankshaft until No. 1 piston is on TDC of compression stroke.
4.
Measure torque required to turn each stud nut in a counterclockwise direction (breakaway torque). Replace stud nuts where breakaway torque is
not 4.5 - 15 ft. lbs. If breakaway torque is still not within specifications after replacing stud nut, the stud must be replaced.
5.
Install stud nut and torque to 17 - 23 ft. lbs. with No. 1 piston at TDC of compression stroke. Using a suitable tool, slowly apply pressure to bleed
down lifter until plunger is completely bottomed. Hold lifter in this position and check clearance between rocker arm and valve. If clearance is not
within specifications, install a longer or shorter pushrod as needed.
6.
On all models, repeat step 5 or 6 for remaining valves. Turn crankshaft 120° at a time in normal direction of rotation and adjust valves following
engine firing order.
Valve Arrangement
Front to Rear
6-300....................................................................................................................................................................................................E-I-E-I-E-I-E-I-E-I-E-I
