TM 5-3805-260-24
CYLINDER HEAD AND VALVES
1. Push rod.2. Cam follower.3. Guide support.4. Rocker arm shaft. 5. Rocker arm.6. Exhaust valve. 7.
Valve seat insert. 8. Intake valve. 9. Valve spring.
The valves and valve system components
control the flow of inlet air and exhaust gases into and
out of the cylinder during engine operation.
The intake and exhaust valves are opened and
closed by movement of these components; crank-shaft,
camshaft, cam followers, push rods, rocker arms, and
valve springs. Rotation of the crankshaft causes rotation
of the camshaft. The camshaft gear is driven by, and
timed to, a gear on the front of the crankshaft. When the
camshaft turns, the cams on the camshaft also turn and
cause the cam followers to go up and down. This
movement makes the push rods move the rocker arms.
The movement of the rocker arms will make the intake
and exhaust valves in the cylinder head open and close
according to the firing order (injection sequence) of the
engine. One valve spring for each valve helps to hold
the valves in the closed position.
There is one intake and one exhaust valve for
each cylinder. The valve seat insert for the exhaust
valve can have replacement. The valve seat for the
intake valve is machined in and is a part of the cylinder
head. When the seat for the intake valve has been
machined to the limits given in the SPECIFICATIONS, it
can be bored (machined) for a valve seat insert. The
valve guide bore is machined in and is a part of the
cylinder head.
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