Westerbeke BCGB - Oil Pressure and Compression Testing; Testing Engine Oil Pressure; Engine Compression Testing

TESTING OIL PRESSURE I ENGINE COMPRESSION
NOTE: WESTERBEKE recommends that the following engine
adjustments be performed by a competent engine mechanic.
The information below is provided to assist the mechanic.
TESTING OIL PRESSURE
To test the oil pressure, remove the hex head plug from the
oil manifold and install a mechanical oil pressure gauge in its
place. After warming up the engine, set the engine speed at
1800 rpm and read the oil pressure gauge.
Oil Pressure Between 3D and 40 psi at 1800/1500 rpm.
Note: A newly started (cold) engine may have an oil pres-
sure up to
70 or 80 psi. A warmed engine can have an oil
pressure as low as. 30 psi. Oil pressure will vary depending
on the load placed on the generator.
OIL GALLERY
LOW OIL PRESSURE
The specified safe minimum oil pressure is 4.3 + 1.4 psi (0.3
+ 0.1 kglcm
2
). A gradual loss of oil pressure usually indicates
worn bearings.
ENGINE COMPRESSION TEST
1. To check the engine's compression pressure, warm up the
engine then shut it down.
2. Remove the three spark plug caps and remove the three
spark plugs.
3. Install a compression adapter and gauge in the spark plug
hole.
4. Close off the raw water intake seacock.
5. Crank the engine with the start motor and unplug the
ignition coil and allow the compression gauge to reach a
maximum reading and record.
6. Measure the compression pressure for all the cylinders.
Ensure that compression pressure differential for each
cylinder is within the specified unit.
Compression pressure should not differ by more than 14 psi (100 Kpa).
7. If a cylinder's compression or pressure differential is
below the limit, add a small amount
of engine oil through
the spark plug hole and repeat steps 4 and
5.
(a) If additional of oil causes an increase of pressure, the
piston ring and/or cylinder wall may be worn or damaged.
(b)
If additional oil does not increase compression pressure
suspect poor valve contact, valve seizure, or valve wear.
8. Reinstall three plugs and ignition wires.
9. Open the raw water thru seacock.
COMPRESSION PRESSURE
178 PSI [1260Kpa] AT 400 RPM
COMPRESSION
GAUGE
(TYPICAL)
ADAPTER
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Engines & Generators
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