Crankshaft Main And Connecting Rod Bearings - Ford LRG-423 Service Manual

01-19 Enaine Service
01-19
SERVICE PROCEDURES (Continued)
Crankshaft Main and Connecting Rod
Bearings
Cleaning
NOTE: Do not scrape gum or varnish deposits from
the bearing shells.
Bearings that are to be reused should be identified so
they can be installed in their original locations.
Clean the bearing inserts and caps thoroughly in
solvent, and dry them with compressed air.
Inspection
Inspect each bearing carefully. Bearings that have a
scored, chipped or worn surface should be replaced.
Typical examples of unsatisfactory bearings and their
causes are shown in the illustration. The copper lead
bearing base may be visible through the bearing
overlay. If the base showing is less than 20 percent of
the total area, the bearing is not excessively worn. It is
not necessary to replace the bearing if the bearing
clearance is within recommended limits. Check the
clearance of bearings that appear to be satisfactory
with Plastigage@ as described in this section.
n
00
A2333843
Item
Part
Number
Description
1
6333 Connecting Rod Bearing
A - Fatigue Failure - Craters or
Pockets
B - Improper Seating - Bright
(Polished) Sections
c - Dirt Scratching, lmbedding
D - Overlay Wiped Out - Lack of
Oil or Improper Clearance
E - Hourglass - Overlay Gone
from Edges
F - Radius Ride
G - Overlay Gone from Mating
Edge, One Side Only. Rod Cap
Shift.
Crankshaft Main or Connecting Rod Bearings
- Fitting Plastigage@ Method
1.
Clean crankshaft journals. Inspect journals and
thrust faces for nicks, burrs or roughness that
would cause premature bearing wear.
When
replacing standard bearings with new bearings,
it is good practice to fit bearing to minimum
specified clearance.
If desired clearance cannot
be obtained with a standard bearing, try a
0.050mm (0.002-inch) undersize bearing set to
obtain proper clearance.
2.
CAUTION: Do not position jack under crankshaft
pulley. Crankshaft post damage will result.
If fitting main bearing in-equipment, position a
jack under counterweight adjoining bearing which
is being checked. Support crankshaft (6303) with
jack so its weight will not compress Plastigage@
and cause an incorrect reading.
3. Place a piece of Plastigage@ D81 L-6002-B, or
equivalent, on bearing surface across full width of
bearing cup and about 6.35mm (l/4 inch) off
center.
1