Service manual

181 CID (3.0L) 4 CYLINDER GM ENGINE
SERVICE MANUAL NUMBER 26
90-861329--1 MARCH 1999 Page 3A-19
2. With engine in No. 1 firing position as determined above, the following valves may be
adjusted:
• No. 1 Cylinder - Exhaust and Intake
• No. 2 Cylinder - Intake
• No. 3 Cylinder - Exhaust
• No. 4 Cylinder - Intake
3. Loosen adjusting nut until lash is felt at push rod, then tighten adjusting nut until all lash
is removed. This can be determined by moving push rod up and down while turning
adjusting nut until all play is removed.
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4. Hydraulic lifters can be adjusted by tightening adjustment nut an additional 3/4-turn.
Valve lash should be checked after engine has run and reached operating temperature.
5. Crank engine one revolution until pointer “0” mark and torsional damper mark are again
in alignment. This is No. 4 firing position. With engine in this position, the following valves
may be adjusted:
• No. 2 Cylinder - Exhaust
• No. 3 Cylinder - Intake
• No. 4 Cylinder - Exhaust
6. Repeat steps 3-4 to adjust other valves.
7. Install Distributor cap, spark plug wires and coil lead.
8. Install rocker arm cover; torque to 40 lb-in. (4.5 Nm).
Engine Running
Following procedure should be completed only if readjustment is required.
1. Run engine until it reaches normal operating temperature, then remove valve cover.
2. With engine running at idle, loosen valve rocker arm nut until valve rocker arm starts to
clatter.
3. Turn rocker arm nut down slowly until clatter just stops. This is zero lash position.
4. Tighten nut 1/4 additional turn and pause 10 seconds until engine runs smoothly. Repeat
additional 1/4 turns, pausing 10 seconds each time, until nut has been tightened 3/4 turn
from zero lash position.
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