-1
Asbestos gaskets contain fibers
that when airborne harm your
health. Use a respirator when handling and &fa//-
ing gaskets.
6.
After the head nuts have been tightened once,
it
is
necessary to tighteneach head nut to thespecified
torque a second time. Follow the same sequence
shown in Figure
9-2.
Failure to re-torque could
result in a blown head gasket.
7.
Recheck torque before engine has run a total of
50
hours.
VALVE
SYSTEM
A
properly functioning valve system is essential for
good engine performance. All generator sets utilize an
L-head type valve design as shown in Figure
9-3.
Access to the valve system can be obtained by remov-
ing the cylinder heads and the valve covers on top of
the engine.
A
valvespring compressor must be used to
remove valves (see Figure
9-4)
from the cylinder block.
Use the following procedures to inspect and service
the valve system.
NOTE:
SEE
VALVE
TAPPET
CLEARANCES
IN
TEXT.
'
VALVE
RETAINER
.
VT-1019 VT-1019
NOTE:
SEE
VALVE
TAPPET
VALVE
ADJUSTING
CLEARANCES
IN
TEXT.
A
.I
7
/
SCREW
FIGURE
9-3.
VALVE SYSTEM
Inspection
Valve Face:
Check the valve face for evidence of burn-
ing, warpage, out-of-round, and carbon deposits (Fig-
ure
9-5).
VT-1018
FIGURE
9-4.
VALVE
SPRING
COMPRESSOR
VT-1017
FIGURE
9-5.
VALVE FACE
Burning and pitting are caused
by
the valve failing to
seat tightly. This condition is often caused by hard
carbon particles on the seat. It may also be due to weak
valve springs, insufficient tappet clearance, warpage,
and misalignment.
Warpage occurs chiefly in the upper stem due to its
exposure
to
intense heat. Out-of-round wear follows
when the seat is pounded by a valve whose head is not
in line with the stem and guide.
If
avalve face is burned
or warped, or the stem worn, install a new one.
Too
much clearancein the intakeguideadmitsairand
oil into the combustion chamber, upsetting carbure-
tion, increasing oil consumption, and making heavy
9-2
Redistribution or publication of this document
by any means, is strictly prohibited.
Redistribution or publication of this document
by any means, is strictly prohibited.
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