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ENGINE ADJUSTMENTS
NOTE: WESTERBEKE recommends that the following engine adjust-
ments be performed
by
a competent engine mechanic.
The
information
below is provided to assist the mechanic.
VALVE CLEARANCE ADJUSTMENT
1. Wann the engine
to
nonnal operating temperature.
2. Pull off the air breather pipe from the rocker cover.
Remove the rocker cover bolts and remove the rocker
cover to expose the rocker shaft and valve assembly.
3. Remove the glow plugs from each of the cylinders to
enable the crankshaft to be easily rotated by hand to
position each cylinder for valve adjustment.
Valves are adjusted with the piston in the cylinder being
adjusted at TOC of its compression stroke.
NOTE:
Retorque the cylinder head bolts before adjusting the
engine
s
valves.
4. Loosen the head bolts in the reverse order of tightening.
13
9
5
1
4
8
12
5. Tighten the head bolts in the order shown. Torque at
85 90 ft -Ib (11.8 -12.5 m-kg)
6. Set the piston of No.1 cylinder to TOC (compression)
and check the valve clearance at each position indicated.
If
the clearance is incorrect, adjust to specifications:
Intake - No.1 and No.2 cylinders; and
Exhaust - No. 1 and No.3 cylinders.
7. Turn the crankshaft once, setting the piston of No. 4
cylinder at TOC (compression) and adjust to the
following specifications:
Intake - No.3 and No.4 cylinders; and
Exhaust - No.2 and No.4 cylinders.
WHEN NO.4 CYLINDER IS AT TOP DEAD CENTER
I
41NTAKE 31NTAKE
4 EXHAUST
EXHAUST 2
2 INTAKE
NTAKE1
f
EXHAUST
I
~
EXHfUST
WHEN NO. 1 CYLINDER IS AT TOP DEAD CENTER
I"!!""'!.""!""!""~
8. Adjust each valve's clearance by inserting a 0.012in
(0.03mm) feeler gauge between the rocker ann and the
valve stem. Make sure to adjust all valves when the
engine is cold.
9. Install the cylinder head cover.
HEAD COVER BOLT TORQUE 2 - 3 ft -Ib (0.3 - 0.45 m-kg)
ENGINE COMPRESSION
Check the compression pressure. To do this, wann the
engine, remove all fuel injectors, or glow plugs, disconnect
the fuel shut-off solenoid wire, and install a compression
adapter in the injector hole or glow plug hole. Connect a
compression tester on the adapter and crank the engine with
the starter motor until the pressure reaches a maximum value.
Repeat this process for each cylinder. Look for cylinders with
dramatically (at least 20%) lower compression than the
average of the others. Compression pressure should not differ
by more than 42.7 psi (3.0 kglcm
2 )
at 200 rpm.
COMPRESSION GAUGE
I
~
COMPRESSION PRESSURE STANDARD 427 PSI al200 RPM (30.0 Kg/em')
COMPRESSION PRESSURE LIMIT
384 PSI al200 RPM (27.0 Kg/em')
LIMIT BETWEEN CYLINDERS
42.7 PSI (3.0 Kg/em')
If
a weak cylinder is flanked by healthy cylinder, the problem
is either valve or piston related. Check the valve clearances
for the weak cylinder, adjust as needed and test again.
If
the cylinder is still low, apply a small amount of oil into
the cylinder to seal the rings and repeat the test.
If
compression comes up - the rings are faulty.
Engines
&
Generators
36
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Troubleshooting
