Connecting Rods; Pistons, Pins And Rings; Crankshaft Journal Measurements; Typical Bearing Failures - Lincoln Continental 1964 Shop Manual

. {135)
A VS B
=
VERTICAL TAPER
C VS D
=
HORIZONTAL TAPER
A VS C AND B VS D
=
OUT-OF-ROUND
CHECK FOR OUT-Of-ROUND AT
I
I
\
\
'
'
EACH END OF JOURNAL
.... -....e--'
FIG.
20-Crankshaft
Journal Measurements
shaft, therefore, the camshaft should
not be replaced until the lobe lift
loss has exceeded 0.005 inch.
The lift of camshaft lobes can be
checked with the camshaft installed
in the engine or on centers. Refer to
"Camshaft Lobe Lift."
Check the distributor drive gear
for broken or chipped teeth.
CRANKSHAFT
CLEANING
Handle the crankshaft with care
to avoid possible fractures or dam-
age to the finished surfaces. Clean
the crankshaft with solvent, then
blow out all oil passages with com-
pressed air.
INSPECTION
Inspect main and connecting rod
journals for cracks, scratches, grooves,
or scores.
Measure the diameter of each
jqurnal in at least four places to
determine out-of-round, taper, or un-
dersize condition (Fig. 20).
CONNECTING RODS
CLEANING
Remove the bearings from the rod
and cap. Identify the bearings if they
are to be used again. Clean the con-
necting rod in solvent, including the
FIG.
21-Cieaning Ring
Grooves
PART 8-1-GENERAL ENGIN£ St~
8-15
RADIUS RIDE
FATIGUE FAILURE
A1021-A
FIG. 22-
Typical Bearing Failures
rod bore and the back of the inserts.
Do not use a caustic cleaning solu-
tion. Blow out all passages with
compressed air.
INSPECTION
The connecting rods and related
parts should be carefully inspected
and checked for conformance to
specifications. Various forms of en-
gine wear caused by these parts can
be readily identified.
A shiny surface on the pin boss
side of the piston usually indicates
that a connecting rod is bent or the
piston pin hole is not in proper re-
lation to the piston skirt and ring
grooves.
Abnormal connecting rod bear-
ing wear can be caused by either a
bent connecting rod, an improperly
machined crankpin, or a tapered
connecting rod bore.
Twisted connecting rods will not
create an easily identifiable wear
pattern, but badly twisted rods will
disturb the action of the entire pis-
ton, rings, and connecing rod as-
sembly and may be the cause of
excessive oil consumption.
Inspect the connecting rods for
signs of fractures and the bearing
bores for out-of-round and taper.
If the bore exceeds the recom-
mended limits and/or if the con-
necting rod is fractured, it should
be replaced.
Check the piston pin to connect-
ing rod bushing clearance. Replace
the connecting rod if the bushing is
so worn that it can not be reamed or
honed for an oversize pin.
Replace defective connecting rod
nuts and bolts.
After the connecting rods are as-
sembled to the piston, check the con-
necting rods for bend or twist on a
suitable alignment fixture. Follow the
instructions of the fixture manufac-
turer.
If
the bend and/or twist is ex-
cessive, the connecting rod should be
straightened or replaced.
PISTONS, PINS AND RINGS
CLEANING
Remove deposits from the piston
surfaces. Clean gum or varnish from
the piston skirt, piston pins, and rings
with solvent. Do not use a caustic
cleaning solution or a wire brush
to clean pistons. Clean the ring
grooves with a ring groove cleaner
(Fig. 21). Make sure the oil ring
slots (or holes) are clean.
INSPECTION
Carefully inspect
th~
pistons for
fractures at the ring lands, skirts,
and pin bosses, and for scuffed,
rough, or scored skirts. If the lower
inner portions of the ring grooves
have high steps, replace the piston.
The step will interfere with ring
operation and cause excessive ring
side clearance.
Spongy, eroded areas near the
edge of the top of the piston are
usually caused by detonation, or
pre-ignition. A shiny surface on the
thrust surface of the piston, offset
from the centerline between the pis-
ton pin holes, can be caused by a
bent connecting rod. Replace pis-
tons that show signs of excessive
wear, wavy ring lands, fractures,
and/ or damage from detonation or
pre-ignition.
Check the piston to cylinder bore
clearance with a tension scale and
ribbon, following the procedure un-
der "Fitting Pistons." Check the ring
side clearance following the proce-
dure under "Fitting Piston Rings" in
Section 2.
If piston pins show signs of frac-
ture or etching and/or wear, replace