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Valves, Valve Mechanisms, and Cylinder Heads Servicing | Up
Construction Mechanic Advanced - Construction methods and practices | Next
Valve Removal |
shown in figure 3-13. On engines with stud-
mounted rocker arms, make the adjustment by
turning the stud nut.
Valves in Block
This type of valve arrangement is not
commonly seen in the field; however, we will
describe the adjustment procedure in case you
should happen to run across this type.
Valves within the block are generally adjusted
“cold”; that is, recommended valve clearance are
given for a cold engine. These valves have
mechanisms quite similar to those of overhead
valves. They are adjusted by removing the side
plates, usually found beneath the intake manifold
on the side of the engine block (fig. 3-14). Since
you must stop this engine to adjust the valves, the
piston in the cylinder to be adjusted must be on
TDC of the compression stroke. You can
determine this by watching the valves of the piston
that is paired with the one that is being set. As
the cylinder that is being positioned is coming up
on the compression stroke, the paired cylinder will
be coming up on the exhaust stroke. Therefore,
an exhaust valve will be open. Just as the exhaust
Figure 3-14.—Adjusting valve in block.
valve closes and the intake valve begins to open,
the cylinder that is to be set will be on TDC of
the compression stroke, and you can set the two
valves. Once the No. 1 cylinder is positioned,
follow through according to the firing order of
the engine, as this makes the job easier and faster.
You may also use this procedure when adjusting
valves on overhead valve engines.
Hydraulically Operated Valves
On engines equipped with hydraulic valve
lifters (fig. 3-1 5), it is not generally necessary to
Figure 3-13.—Adjusting overhead valves.
Figure 3-15.—Hydraulic valve lifter.
3-16
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