ADJUSTMENTS

NOTE: The 1983–84 (OHV) 1800 engine with automatic transmission use hydraulic lash adjusters; no periodic adjustment is necessary.

The valve lash should be checked and adjusted, if necessary, after the first 1000 miles (1100 km) of operation and then every 6 months/6000 miles (10,000 km) on 1970–73 models; every 12 months/12,000 miles (19,000 km) on 1974–79 models and every 15 months/15,000 miles (24,000 km) on 1980 and later models.

Before adjusting the valves, make sure the cylinder head nuts/bolts are tightened to the proper specifications. Refer to Section 3

1. Rotate the engine so that the No. 1 piston is at Top Dead Center (TDC) of its compression stroke. To determine TDC, remove the distributor cap and the plastic flywheel housing dust cover (normally aspirated engines only). The No. 1 piston is at top dead center when the distributor rotor is pointing to the No. 1 spark plug lead terminal (as though the distributor cap were in place) and the 0 mark on the flywheel or front pulley is opposite the pointer on the housing or front cover.
2. Check the clearance of both the intake and exhaust valves of the No. 1 cylinder by inserting a feeler gauge between each valve stem and rocker arm. See the Tune-Up Specifications chart for the proper stem-to-rocker arm clearance.
3. If the clearance is not within specifications, loosen the locknut with the proper size metric box wrench and turn the adjusting stud either in or out until the valve clearance is correct. The stud should just touch the gauge. Don't clamp the gauge tightly between the stud and head of the valve.
4. Tighten the locknut and recheck the valve stem-to-rocker clearance.
5. The rest of the valves are adjusted in the same way. Bring each piston to TDC of its compression stroke, then check and adjust the valves for that cylinder. The proper valve adjustment sequence is 1–3–2–4, which is the firing order.
6. To bring the No. 3 piston to TDC of its compression stroke, rotate the crankshaft 180°and make sure that the distributor rotor is pointing to the No. 3 spark plug terminal. Rotate the crankshaft 180°after each valve adjustment before going on to the next adjustment.
7. When the valve adjustment is complete, install the distributor cap, the valve covers with new gaskets and the dust cover on the flywheel housing port.

   Fig. 1: Remove the valve covers from both sides of the engine

   Fig. 2: Check the clearance of the valves by inserting a feeler gauge between each valve stem and rocker arm

   Fig. 3: If the clearance is not within specifications, loosen the locknut and turn the adjusting stud