User Manual

SENR9977 39
TestingandAdjustingSection
3. Slowly apply air pressure to the wastegate so
that the actuat
or rod moves 1.0 mm (0.039 inch).
The air pressure should be within 107 to 117 kPa
(15.5 to 17.0 psi). Ensure that the dial indicator
returns to zer
o when the air pressure is released.
Repeat the test several times. This will ensure that
an accurate reading is obtained.
4. For more information on installing a new
turbocharger, contact your Perkins dealer or your
Perkins dist
ributor.
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Compressio n
- Test
Thecylindercompressiontestshouldonlybeusedin
order to compare the cylinders of an engine. If one or
more cylinde
rs vary by more than 350 kPa (51 psi),
the cylinder and related components may need to
be repaired.
A compression test should not be the only method
which is used to determine the condition of an engine.
Other test
sshouldalsobeconductedinorderto
determine if the adjustment or the replacement of
components is required.
Before the performance of the compressio n test,
make sure that the following conditions exist:
•
The battery is in good condition.
•
The batter
y is fully charged.
•
The starting motor operates correctly.
•
The valve lash is set correctly.
•
All fuel in
jectors are removed.
•
The fuel supply is disconnected.
1. Install a gauge for measuring the cylinder
compression in the hole for a fuel injector.
2. Operate the starting motor in order to turn the
engine. Record the maximum pressure which is
indicate
d on the compression gauge.
3. Repeat Steps 1 and 2 for all cylinders.
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Engine Valve Lash -
Inspect/Adjust
To prevent possible injury, do not us e the starter
to turn the flywheel.
Hot engine components can cause burns. Allow
additional time for the engine to cool before mea-
suring valve
clearance.
Valve Lash Set
ting
Valvelashsetting
Inlet valve ........................... 0.2 mm (0.008 inch)
Exhaust valve ................... 0.45 mm (0.018 inch)
Refer to Systems Operation, “Engine Design” for the
location of the cylinder valves.
Valve Lash Adjustment
If the valve lash requires adjustment several times
in a short period of time, excessive wear exists in
a different p
art of the engine. Find the problem and
make necessary repairs in order to prevent more
damage to the engine.
Not enough valve lash can be the cause of rapid
wear of the camshaft and valve lifters. Not enough
valvelashc
an indicate that the seats for the valves
are worn.
Valves beco
me worn due to the following causes:
•
Fuel injectors that operate incorrectly
•
Excessive dirt and oil are present on the filters f or
the inlet air.
•
Incorrect fuel settings on the fuel injection pump.
•
The load ca
pacity of the engine is frequently
exceeded.
Toomuchva
lvelashcancausebrokenvalvestems,
springs, and spring retainers. Too much valve lash
canbeanindicationofthefollowingproblems:
•
Worn camshaft and valve lifters
•
Worn rocke
rarms
•
Bent pushrods