Chevrolet 30 Series 1967 Service Manual page 290

ENGINE 6-10
Fig. 17—C ooling System Pressure Test
2. With the engine running at idle, back off valve rocker
arm nut until the valve rocker arm starts to clatter.
3. Turn rocker arm nut down slowly until the clatter
just stops. This is the zero lash position.
NOTE: Oil deflector clips are commercially
available (fig. 18).
4. Turn nut down 1/4 additional turn and pause 10
seconds until engine runs smoothly.
ditional 1/4 turns, pausing 10 seconds each time,
until nut has been turned down
the zero lash position.
NOTE:
done slowly to allow the lifter to adjust itself to
prevent the possibility of interference, between
the inlet valve head and top of piston, which
might result in internal damage and/or bent push
rods. Noisy lifters should be replaced.
5. Repeat Steps 2, 3 and 4 to adjust the rest of
the valves.
. Clean gasket surfaces on cylinder heads and rocker
6
arm covers with degreaser then install rocker arm
covers, using new gaskets, and torque bolts to
specifications.
Repeat ad-
Fig. 18— O il Deflector Clips Installed
This 1 turn preload adjustment must be
CHEVROLET TRUCK SERVICE M ANUAL
full turn from
1