2. INSPECTION AND ADJUSTMENT (4) Intake/exhaust valve clearance adjustment Make measurement and adjustment while the engine is cold. (a) Valve clearance measurement 1) Remove the rocker arm cover above cylinder head. 2) Set the No.1 cylinder in the compres- sion TDC. Turn the crankshaft to bring the piston of the No.1 cylinder to its compression top dead center while watching the rocker arm motion, timing scale and the top mark position of the crankshaft pulley. (Position where both the intake and exhaust valves are closed.) Notes: The crankshaft shall be turned clockwise as seen from the radiator side.
The No.1 cylinder position is on the op- posite side of the radiator and the igni- tion order shall be 1-3-4-2-1 at 180° intervals. Since the intake and exhaust valve rock- er arms are operated the same and there is a clearance between the arm and valve generally at the top dead cen- ter, the position can be checked by means of the play when the arm head is held with a hand. Also see that the crankshaft pulley top mark is positioned at zero on the timing scale. If there is no valve clearance, inspection in the disas- sembled state is necessary since the valve seat may be worn abnormally.
3) Valve clearance measurement In case of 2-valve cylinder head insert a thickness gauge between the rocker arm and valve cap, and record the mea- sured valve clearance. In case of 4-valve head insert a thick- ness gauge between the rocker arm and the cross head, and record the measured valve clearance. (Use it as the data for estimating the wear state.) 4) Adjusting other cylinders In case of 4-cylinder engines, turn the crankshaft 180° and make adjustment for the No.3 cylinder. Then adjust the No.4 and No.2 cylinders in this order. The cylinder to be adjusted first does not have to be the No.1 cylinder.
Select and adjust the cylinder where the piston is the nearest to the top dead center after turning, and make adjustment for other cylinders in the order of ignition by turning the crankshaft 180° each time. 2-20 82E-5 – 98E-5 SERIES