2. Turn off the engine and remove the air cleaner assembly from the engine. Label all hoses and wires going to the air filter for ease of installation (photo).
Use tape to mark the vacuum hoses that connect to the air filter so you don't mix them up during installation
3. Remove the crankcase ventilation valve and spark plug wires from the camshaft cover. Use a piece of wire to tie the throttle cable outside the work area.
4. Remove the camshaft cover bolts, being careful not to lose the washers (photo).
Remove the camshaft cover bolts |
Make sure you have removed the camshaft cover bolt washers |
5. Wrap the end of a large screwdriver in a rag and use it to carefully pry the camshaft cover free (photo) Remove the engine cover and remove the gasket.
Remove the camshaft cover using a screwdriver with the end wrapped in a rag to avoid damaging the aluminum housing
6. Place piston No. 1 at top dead center (TDC) on the compression stroke. To do this, number the spark plug wires, then remove all the spark plugs from the engine. Locate the spark plug wire for cylinder #1 and trace it to the distributor. Place the number 1 on the distributor housing directly below the #1 spark plug wire clamp on the distributor cap. Do the same with the remaining wires, marking their number on the distributor housing, then remove the cover with the wires from the gel distributor (photo).
Mark the distributor wires with masking tape |
Mark the location of the distributor wire on the housing |
7. Slowly turn the crankshaft clockwise with a wrench or socket on the large bolt on the front of the crankshaft or (if the drive belt is sufficiently tensioned) place the rotor on the generator so that the notch on the crankshaft pulley aligns with the pointer (photo). The rotor should point toward the number 1 you marked on the distributor housing (photo). If this isn't the case, rotate the crankshaft 360° clockwise. If the rotor now points to the number 1 on the distributor housing, then piston #1 is at TDC on the compression stroke, meaning you can check and adjust the clearances of the intake and exhaust valves of cylinder #1, the intake valve of cylinder #2, and the exhaust valve of cylinder #3. The intake valves are located on the rear of the engine (facing the thermal insulation probe), and the graduation ones are on its front side.
With the spark plugs removed, place a socket or wrench on the alternator nut and crank the engine (if the drive belt is tensioned correctly) |
The crankshaft pulley notch is aligned with the TDC mark |
The distributor rotor contact points to the #1 spark plug wire mark (arrow) on the housing (i.e. cylinder #1 is in BMT)
8. Insert a feeler gauge of the appropriate size (see Specifications) between the valve stem and the rocker arm. If the feeler gauge fits between them with a little effort, then the gap is correct and no adjustment is required.
9. If the feeler gauge does not fit into this gap or fits too loosely, loosen the adjusting screw lock nut and gently tighten or loosen the adjusting screw to adjust the gap (photo).
10. While holding the adjusting screw still with a screwdriver, firmly tighten the lock nut (photo). Recheck the clearance to ensure it has not changed.
11. Rotate the crankshaft a full revolution (360°), which will bring the piston of cylinder No. 4 to top dead center on the compression stroke. Check this by making sure the rotor points to the position of spark plug wire #4. Check and adjust the clearance of the exhaust valve of cylinder #2, the intake valve of cylinder #3, and the intake and exhaust valves of cylinder #4.
12. Check the tightening torques of the cylinder head bolts (the engine is hot), using a torque wrench. Loosen one bolt a quarter turn, then tighten it to the specified torque Specifications. Repeat the procedure on all cylinder head bolts in the sequence shown in the illustration.
13. Install the camshaft cover (use a new gasket) and tighten the mounting bolts evenly and securely to the torque specified in the Specifications (see Section 2A Specifications).
14. Install the spark plugs, distributor cap and spark plug wires. Install the air filter and connect all associated hoses, electrical connectors to the power supply and vacuum lines.
15. Start the engine and check the tightness of the connection between the camshaft cover and the cylinder head.