Service manual

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26
Page 3A-56 90-861329--1 MARCH 1999
Cleaning and Inspection
1. Wash crankshaft in solvent and dry with compressed air.
2. Measure main bearing journals and crankpin dimensions with a micrometer for
out-of-round, taper or undersize (see “Specifications”).
3. Check crankshaft for runout (by supporting at front and rear main bearings journals in
V-blocks) and check at front and rear intermediate journals with a dial indicator (see
“Specifications”).
4. Replace or recondition crankshaft if not within specifications.
Installation
1. If a new crankshaft is being installed, remove timing sprocket from old crankshaft and
reinstall on new crankshaft as outlined.
IMPORTANT: Be sure that all bearings and crankshaft journals are clean.
2. Install main bearings in engine block as shown.
72359
a
b
c
Main Bearing Inserts
a-Lower Bearing Insert
b-Upper Bearing Insert
c-Oil Groove
3. Carefully lower crankshaft into place. Be careful not to damage bearing surface.
4. Check clearance of each main bearing, following procedure outlined under “Main Bear-
ings.” If bearing clearances are satisfactory, apply engine oil to journals and bearings.
5. Install main bearing caps. Torque bolts to 75 lb-ft (102 Nm). When tightening rear main
bearing cap, follow procedure outlined under “Main Bearings.”
6. Check crankshaft end play as previously outlined.
7. Install rear main seal retainer and seal. Torque fasteners to 133 lb-in. (15 Nm).
8. Check clearance for each connecting rod bearing, following procedure under “Connect-
ing Rod Bearings.” If bearing clearances are satisfactory, apply engine oil to journals and
bearings.
9. Install rod caps and torque nuts to 45 lb-ft (61 Nm).
10. Turn crankshaft so mark on timing sprocket is facing camshaft.
Index