ENGINEMAN 1 & C
Excessive Wear
A. Symptoms:
1. Low compression
2. Hard starting
3. Loss of power
4. Smoky exhaust
5. Waste of fuel
6. Excess oil
consumption
7. Poor engine
operation
(Other factors
which may cause
low compression
pressure:
a. Leaking cylinder
valves
b. Faulty injector
gasket
c. Faulty head
gasket
d. Leaking after-
chamber valves
e. Clogged intake
ports
f. Intake air header
leakage
g. Faulty blower
h. Clogged air
filter)
Other factors which
may cause excessive
B. Causes:
oil consumption:
a. Loose bearings
b. High lube oil
temperatures
c. Oil line leakage
d. Improper oil)
1. Inadequate lubrication
2. Excessive piston heat
3. Rings damaged during installation
4. Ring- to-land clearance insufficient
5. Dust or dirt in intake air
6. Dirt in lube oil or fuel
7. Rings stuck in grooves
8. Worn cylinder liners
Sticking
Breakage
C. Symptoms:
1. Low compres-
sion
2. Loss of power
3. Smoky exhaust
4. Excessive oil
consumption
5. Blow-by forcing
fumes from
crankcase
D. Causes
1. Improper ring-
to-land clear-
ance
2. Insufficient ring
pressure
3. Excessive oper-
ating tempera-
ture
4. Improper oil
5. Improper in-
stallation
E. Symptoms:
1. Hard starting
2. Loss of power
3. Excess oil
consumption
4. Possible emis-
sion of smoke
from crank-
case breather
F. Causes:
1. Cylinder liner
ridge
2. Cylinder port
damage
3. Insufficient gap
clearance
4. Insufficient
clearance be-
hind ring
Figure 3-18.—Piston ring troubles, their symptoms and causes.
121.2
with a thickness gage, and must be made com-
pletely around the piston.
PISTON RINGS
Replace most damaged or excessively worn
pistons. Since replacement of damaged pistons is
usually necessary, shipboard repair parts should
always be maintained at full allowance.
The troubles to which piston rings are subject
and their symptoms and causes are listed in figure
3-18.
All symptoms and causes shown for ring wear
are either directly and indirectly related to
3-28
