GMC 1989 Light Duty Truck, Repair Manual, Page: 480 / 998

6A4-26 4.8 LITER L6
T ig h ten
i?
0
• All bolts (138 and 139) EXCEPT THE REAR
MAIN BEARING CAP BOLTS to 90 N-m (65 ft.
lbs.).
M easure (Figure 50)
Crankshaft end play.
1. Tap the end of the cra n k s h a ft (154) first
rearward then forward with a lead hammer.
This will line up the rear main bearing and
crankshaft thrust surfaces.
2. Tighten the rear main bearing cap bolts (138)
to 90 N-m (65 ft. lbs.).
3. With the crankshaft forced forward, measure
at the front end of the rear main bearing with a
feeler gage (figure 50). The proper clearance
is 0.002-0.006-inch.
Inspect
C ra n k s h a ft (154) fo r b in d in g . Try tu rn in g the
crankshaft to check for binding. If the crankshaft
does not turn freely, loosen the bolts (138 and 139),
one pair at a time, until the tight bearing is located.
Burrs on the bearing cap, foreign matter between
the insert and the block or the bearing cap, or a
faulty insert could cause a lack of clearance at the
bearing.
CAMSHAFT INSTALLATION
Install or C o nnect (Figures 5 and 51)
• C o a t th e c a m s h a ft lo b e s w ith E n g in e O il
S u p p le m e n t (GM p a rt n u m b e r 1051396) o r
equivalent. Coat the bearing journals with engine
oil.
1. Camshaft (182) into the block (115). Take care not to
damage the cam shaft bearings (98 and 99).
Im portant
• Align the tim ing marks (figure 51).
2. Screws (93).
T ig h ten
• Screws (93) to 9.0 N-m (80 in. lbs.).
TIMING GEAR COVER
INSTALLATION
-►+ Install or C onnect (Figures 5 and 52)
Tool Required:
J-35468 Seal Installer and Centering Tool
• Apply engine oil to the lips of the seal (158).
1. J-35468 to the seal (158). The tool is necessary to
properly “ center” the front seal on the crankshaft. If
the seal is not centered, it may be damaged when
the vibration dam per is installed, or it may fail
prematurely.
2. Gasket (166) to the block (115).
3. Timing gear cover (157), with the tool, to the block
(115) (figure 52).
4. Bolts (164).
Q
T ig h ten
• Bolts (164) to 9.0 N-m (80 in. lbs.).
F-02325
Fig u re 5 2 — Front C over C enterin g Tool