Downloaded from www.Manualslib.com manuals search engine (5) Install bearing cap and connecting rod on the
journal and tighten bolts to 27 N´m (20 ft. lbs.) plus a
90É turn. DO NOT rotate crankshaft. Plastigage will
smear, resulting in inaccurate indication.
(6) Remove the bearing cap and determine amount
of bearing-to-journal clearance by measuring the
width of compressed Plastigage (Fig. 29). Refer to
Engine Specifications for the proper clearance.Plas-
tigage should indicate the same clearance
across the entire width of the insert. If the
clearance varies, it may be caused by either a
tapered journal, bent connecting rod or foreign
material trapped between the insert and cap or
rod.
(7) If the correct clearance is indicated, replace-
ment of the bearing inserts is not necessary. Remove
the Plastigage from crankshaft journal and bearing
insert. Proceed with installation.
(8) If bearing-to-journal clearance exceeds the
specification, determin which services bearing set to
use the bearing sizes are as follows:
Fig. 25 Connecting Rod Bearing Inspection
1 ± UPPER BEARING HALF
2 ± MATING EDGES
3 ± GROOVES CAUSED BY ROD BOLTS SCRATCHING
JOURNAL DURING INSTALLATION
4 ± WEAR PATTERN Ð ALWAYS GREATER ON UPPER
BEARING
5 ± LOWER BEARING HALF
Fig. 26 Locking Tab Inspection
1 ± ABNORMAL CONTACT AREA CAUSED BY LOCKING TABS
NOT FULLY SEATED OR BEING BENT
Fig. 27 Scoring Caused by Insufficient Lubrication
or by Damaged Crankshaft Pin Journal
Fig. 28 Piston and Connecting RodÐInstallation
1 ± ªFº TOWARD FRONT OF ENGINE
2 ± OIL SLINGER SLOT
3 ± RING COMPRESSOR
4 ± SPECIAL TOOL 8507
9 - 26 4.7L ENGINEDN
SERVICE PROCEDURES (Continued)
Downloaded from www.Manualslib.com manuals search engine (9) Repeat the Plastigage measurement to verify
your bearing selection prior to final assembly.
(10) Once you have selected the proper insert,
install the insert and cap. Tighten the connecting rod
bolts to 27 N´m (20 ft. lbs.) plus a 90É turn.
Slide snug-fitting feeler gauge between the con-
necting rod and crankshaft journal flange (Fig. 30).
Refer to Engine Specifications for the proper clear-
ance. Replace the connecting rod if the side clearance
is not within specification.
CRANKSHAFT MAIN BEARINGS
INSPECTION
Wipe the inserts clean and inspect for abnormal
wear patterns and for metal or other foreign material
imbedded in the lining. Normal main bearing insert
wear patterns are illustrated (Fig. 31).
NOTE: If any of the crankshaft journals are scored,
remove the engine for crankshaft repair.Inspect the back of the inserts for fractures, scrap-
ings or irregular wear patterns.
Inspect the upper insert locking tabs for damage.
Replace all damaged or worn bearing inserts.
MAIN BEARING JOURNAL DIAMETER
(CRANKSHAFT REMOVED)
Remove the crankshaft from the cylinder block.
Refer to Crankshaft in this section for procedure.
Clean the oil off the main bearing journal.
Determine the maximum diameter of the journal
with a micrometer. Measure at two locations 90É
apart at each end of the journal.
The maximum allowable taper is 0.008mm (0.0004
inch.) and maximum out of round is 0.005mm (0.002
inch). Compare the measured diameter with the jour-
Fig. 29 Measuring Bearing Clearance with
Plastigage
1 ± PLASTIGAGE SCALE
2 ± COMPRESSED PLASTIGAGE
Bearing
MarkSIZE USED WITH
JOURNAL SIZE
.025 US.025 mm 50.983-50.967 mm
(.001 in.) (2.0073-2.0066 in.)
Std.STANDARD 50.992-51.008 mm
(2.0076-2.0082 in.)
.250 US.250 mm 50.758-50.742 mm
(.010 in.) (1.9984-1.9978 in.)
Fig. 30 Checking Connecting Rod Side ClearanceÐ
Typical
Fig. 31 Main Bearing Wear Patterns
1 ± UPPER INSERT
2 ± NO WEAR IN THIS AREA
3 ± LOW AREA IN BEARING LINING
4 ± LOWER INSERT
DN4.7L ENGINE 9 - 27
SERVICE PROCEDURES (Continued)
