Undersize Main Journals (5.0L And 5.7L Engines) - GMC T Series 1994 Repair Manual

Selective fitting of both rod and main bearing inserts
is necessary to obtain close tolerances. For this reason
you may use, for example, one half of a 0.0254-mm
0.001
( -inch) undersize insert which will decrease the
clearance 0.0127 mm (0.0005-inch) from using a full
standard bearing.
UNDERSIZE MAIN JOURNALS (5.0L AND 5.7L
ENGINES)
• On 5.0L and 5.7L engines, when a production
crankshaft cannot be precision fit by the method
described previously, it is then ground 0.2286-mm
(0.009-inch) undersize ON ONLY THOSE MAIN
JOURNALS THAT CANNOT BE PROPERLY FIT­
TED. ALL JOURNALS WILL NOT NECESSARILY
BE GROUND. A 0.2286-mm (0.009-inch) undersize
bearing or 0.2540-mm (0.010-inch) undersize bear­
ing will then be used for precision fitting in the
same manner as previously described.
OVERSIZE REAR MAIN BEARING THRUST FACES
(5.0L AND 5.7L ENGINES)
• Some 5.0L and 5.7L production engines may have
re a r m a in b e a r in g s th a t a re 0 .2 0 3 2
(0.008-inch) wider than standard across the thrust
faces.
• The crankshaft on these engines can be identified
by " .008"stamped on the rear counterweight.
• If the rear main bearings are replaced, they must
have the proper distance between thrust faces to
obtain correct crankshaft end play.
Install or Connect (Figures 67, 68, and 69)
N O T IC E : F o r s t e p s 4 a n d 5, r e f e r to " N o t i c e "
o n p a g e 6 A 5 -1 .
1. Upper main bearing inserts to the block.
Important
• If any undersized bearings are used, make sure
they are fitted to the proper journals.
2
. Crankshaft.
3. Lower main bearing inserts to the main bearing
caps.
Measure
• Main bearing clearance. Refer to SECTION
• Apply engine oil to the main bearing inserts.
4. Main bearing caps (except rear cap) and bolts to
the block.
Tighten
a
Main bearing cap bolts to specifications.
— 5.0L and 5.7L engines:
• Outer bolts on #2, #3, and #4 main bear­
ing caps: 95 N-m (70 lbs. ft.).
•A ll others: 110 N-m (80 lbs. ft.).
— 7.4L engines: 150 N-m (110 lbs. ft.).
135
136
mm
130. Crankshaft
131. Rear Seal
132. Rear Main Bearing Cap
133. Main Bearing Cap
134. Bolt
135. Lower Main Bearing Insert
136. Upper Main Bearing Insert
Figure 67— Crankshaft and Components (7.4L
6
A.
A. Anaerobic Sealer
130. Crankshaft
131. Rear Seal
132. Rear Main Bearing Cap
Figure 68— Applying Sealant to the Block (7.4L
133 134
F9332
Engines)
F9350
Engines)
130