Valve Clearance: Adjustments
Adjusting Valves
The clearance between the heel of the cam lobe and the bucket-type cam follower is adjustable by means of the replaceable adjusting disks (shims).
The adjusting disks are available in twenty-six different thicknesses from 3.00 to 4.25 mm (.1181 to .1673 in.). The disks most frequently required in making adjustments fall in the thickness range of 3.55 to 3.80 mm (.1397 to .1496 in.). Table I lists the available disks by thickness and part number. The thickness of each disk is etched on its underside.
You can adjust the valves with the engine hot-coolant temperature approximately 35°C (95°F) and above-or with the engine cold. However, the clearance will be different depending on whether the engine is hot or cold.
To adjust valve clearance:
1. Remove the socket-head flanged nut from the camshaft drive belt upper cover.
2. Remove the eight nuts and the cylinder head cover retaining plates. While raising the camshaft drive belt upper cover slightly for clearance, carefully lift off the cylinder head cover and its gasket. It the gasket is stuck to the cylinder head, use a dull knife to separate the gasket from the head.
3. Using a wrench on the bolt that is in the center of the crankshaft pulley, hand-turn the crankshaft clockwise until both cam lobes for the No.1 (right) cylinder are pointing upward.
NOTE - The cylinders are numbered consecutively from the right (curb side) to the left (driver's side) of the engine. For example, the No.4 cylinder is at the end of the engine that is bolted to the flywheel bellhousing of the transaxle.
4. To determine the valve clearance, insert feeler gauges of various thicknesses between the cam lobes and the adjusting disks.
NOTE - With the engine hot, the intake valve clearance should be between 0.20 and 0.30 mm (.008 and .012 in.); exhaust valve clearance should be between 0.40 and 0.50 mm (.016 and .020 in.). With the engine cold, the intake valve clearance should be between 0.15 and 0.25 mm (.006 and .010 in.); exhaust valve clearance should be between 0.35 and 0.45 mm (.014 and .018 in.).
5. If either the intake or the exhaust valve clearance is incorrect, write down the actual clearance that you have measured. Then depress the cam followers and lift out the adjusting disk(s) using the special tools (US 4476) and (VW 546) for (1980 through 1982 vehicles), or (US 4476) and (2078) for (1983-1987) vehicles.
Adjusting disk being removed from 1980 through 1982 cylinder head. Special tool depresses both cam tollowers simultaneously. Special pliers (Tool US 4476) are used to remove disc from cam follower.
Adjusting disk being removed from 1983 cylinder head. Special tool 2078 is needed to depress both cam followers simultaneously because of greater distance between valve guides by comparison to earlier models. Special pliers (Tool US 4476) used to remove disk is same for all years.
6. Read the thickness that is etched on the underside of the removed disk. (If the number has worn off, check the disk thickness with a micrometer.) Then determine the thickness of the required replacement disk as described in one of the next two steps.
7. If the measured clearance was less than the specified clearance range for the valve, subtract the measured clearance from the specified maximum clearance. Then subtract the difference from the thickness of the original disk in order to determine the thickness of the required replacement disk. If the computed thickness comes out equal to a standard disk thickness, or if the computed thickness is less than astandard disk thickness, use the next thicker disk.
8. If the measured clearance was greater than the specified clearance range for the valve, subtract the specified maximum clearance from the measured clearance. Then add the difference to the thickness of the original disk in order to determine the thickness of the required replacement disk. If the computed thickness comes out equal to a standard disk thickness, or if the computed thickness is less than a standard disk thickness, use the next thicker disk.
9. Install the required replacement disk(s) with the etched numbers toward the cam follower. Remove the special cam follower depressing tool. Then recheck the clearance to make sure that it is within the specified range.
10. Using a wrench on the bolt that is in the center of the crankshaft, hand-turn the crankshaft 180° clockwise and repeat steps 1 through 8 on the No.3 cylinder. Hand-turn the crankshaft another 180° and adjust the valves of the No.4 cylinder, and, finally, 180° farther to adjust the valves of the No.2 cylinder.
11. Install the cylinder head cover. Torque the bolts and the socket-head flanged nut for the belt upper cover to 10 Nm (7.5 ft. lb.).