25. Refer to Subsection 11H and fill the
cooling system and lubrication system.
26. Before starting the engine, perform
an engine tune-up as outlined in Sub-
s e c t i o n 11H.
VALVE AND INJECTOR OPERATING
MECHANISM
Description
Three rocker arms are provided for each
cylinder; the two outer arms operate the
Figure 11B-38. Lubrication of Valve
exhaust valves and the center arm oper-
O p e r a t i n g Mechanism
ates the fuel injector.
and cam followers. The oil then drains
E a c h set of three rocker arms pivots on a
from the top deck of the cylinder head
shaft supported by two brackets. A
through oil holes in the cam followers,
single bolt secures each bracket to the
into the camshaft pockets in the cylinder
top of the cylinder head. Removal of the
block and back to the oil pan.
two bracket bolts permits the rock arm
assembly for one cylinder to be raised,
The cam follower rollers are lubricated
providing easy access to the fuel injector
with oil from the cam followers, oil
and the exhaust valve springs.
picked up by the camshaft lobes and by
oil emitted under pressure from milled
The rocker arms are operated by the
slots in the camshaft intermediate bear-
camshaft through cam followers and short
ings.
push rods extending through the cylin-
der head.
Service
Each cam follower operates in a bore in
the cylinder head. A guide for each set
Some service operations may be per-
of three cam follower is attached to the
formed on the valve and injector operat-
bottom of the cylinder head to retain the
ing mechanism without removing the
cam followers in place and to align the
cylinder head:
cam follower rollers with the camshaft
lobes.
1. Adjust valve clearance.
A coil spring, inside of each cam
2. Replace a valve spring.
follower, maintains a pre-determined load
on the cam follower to ensure contact of
3. Replace or adjust an exhaust valve
the cam roller on the camshaft lobe at all
bridge or replace a valve bridge guide.
times.
4. Replace a rocker arm.
Lubrication
5. Replace a rocker arm shaft or
bracket.
The valve and injector operating mech-
anism is lubricated by oil from a longi-
6. Replace a fuel injector.
tudinal oil passage on the camshaft side
of the cylinder head, which connects
I t is also possible to replace a push rod,
with the main oil gallery in the cylinder
push rod spring, the spring seats or a
Oil from this passage flows
block.
cam follower without removing the cylin-
through drilled passages in the rocker
der head. However, these parts are
shaft bracket bolts to the passages in
more easily changed from the lower side
the rocker arm shaft to lubricate the
w h e n the cylinder head is off the engine.
rocker arms (see Figure 11B-38).
Both
methods
are
covered
in
this
section.
Overflow oil from the rocker arms lubri-
cates the exhaust valves, valve bridges
11B-26
