How to set Jetta valve?

Jetta valve clearance can be adjusted in the repair shop. Jetta valve clearance adjustment method is as follows:

1. Preheat the engine until the coolant temperature reaches 80℃-90℃, open the timing mark inspection holes on the clutch housing and cylinder head cover to ensure that the cylinder head bolts are tightened to the specified torque;

2. Turn the crankshaft so that the "0" engraved line on the flywheel is aligned with the marked line on the clutch housing, and confirm that the cambered surface of the rocker arm of the intake and exhaust valve of the first cylinder is in contact with the cam base circle of the camshaft, that is, the piston of the first cylinder is at the compression top dead center (if the rocker arm is in contact with the cam, the crankshaft should rotate 360), and the valve is in the closed position at this time;

3. Loosen the lock nut 2 of the adjusting screw 1 and turn the adjusting screw with a screwdriver to make the clearance between the lower end face of the screw and the upper end face of the valve stem 3 reach the specified clearance value (determined by the thickness of the thickness gauge). Keep the screwdriver still, tighten the lock nut to the specified torque, and then insert the thickness gauge into the gap A for re-inspection, so that the gap between the intake valve and the exhaust valve of the first cylinder can be adjusted;

4. Then turn the crankshaft clockwise (viewed from the front end of the engine), and adjust the valve clearance of the next ignition cylinder according to the ignition sequence of 1-3-4-2 for every revolution of the 4-cylinder engine. For a 3-cylinder engine, it can be adjusted according to the ignition sequence of 1-2-3 every 240 revolutions (the rotation angle of crankshaft can be converted by the number of teeth of flywheel ring gear).