2-41. ENGINE ASSEMBLY FROM SUBASSEMBLIES (Contd)
l During assembly operations, it is important to closely inspect each unit
to make sure nothing has been overlooked during inspection and repair.
Plugs should be checked for tightness, parts kept clean, openings
covered, and machined surfaces protected. Application of lubricant
should be performed from covered containers.
l Work area should be clean, well-ventilated, and free of blowing dirt
l In some cases, flanged head fasteners may be present instead of
standard fasteners and washers. In all cases, washers should be used
when replacing a flanged head fastener with a standard fastener.
l For general assembly instructions, refer to para. 2-12.
l Assembly procedures for pre-1990, 1990 and above 6.2L and 6.5L
engines are basically the same. Any differences in procedures are noted.
Some replacement parts are different. Refer to para. 1-10 to determine
engine model before ordering replacement parts.
a. Crankshaft and Main Bearings
l Measure outside diameter of crankshaft main bearing journals to
determine what thickness main bearings to install.
l Main bearings are of the precision insert type and do not utilize shims for
adjustment. If clearances are found to be excessive, a new bearing, both
upper and lower halves, will be required. Service bearings are available in
standard size and undersize.
l Selective fitting of both rod and main bearing inserts is necessary in
production in order to obtain close tolerances. For this reason you may find
one-half of a standard insert with one half of a 0.001 in. (0.025 mm)
undersize insert, which will decrease the clearance 0.0005 in. (0.013 mm)
from using a full standard bearing.
1. Remove all capscrews (1) and (2) and bearing caps (3) and install upper halves of main bearings (7)
in cylinder block (6).
2. Install lower halves of main bearings (4) in bearing caps (3).
Crankshaft must be supported during removal and installation. Failure to
support crankshaft may cause injury to personnel or damage to equipment.
3. Install crankshaft (8) in cylinder block (6).
The gaging plastic shall be positioned the full width of the bearing and
centered on the bearing journal when the bearing cap is installed.
4. Position gauging plastic on bearing journal (5) the full width of the bearing (4) and parallel to the
center line of the crankshaft (8).