GMC 1989 Light Duty Truck Repair Manual page 487

All specifications are in INCHES unless otherwise noted.
CRANKSHAFT:
Main
Taper
Journal
Out of
Round
Main
Bearing
Clearance
Crankshaft End Play
Taper
Crankpin
Out
Round
Rod Bearing
Clearance
Rod Side Clearance
CAMSHAFT:
Lobe
Lift ± 0.002
Journal Diameter
Camshaft Runout
Camshaft End Play
VALVE SYSTEM:
Lifter
Rocker Arm Ratio
Valve Lash
Face Angle (Intake & Exhaust)
Seat Angle (Intake & Exhaust)
Seat Runout (Intake & Exhaust
Seat Width
Production
Stem
Clearance
Service
Free Length
Valve Pressure
Spring lbs. @ in.
(Outer) Installed Height
Valve
Spring
Approx. # of Coils
Damper
SPECIFICATIONS
ENGINE SPECIFICATIONS (CONT.)
Diameter
Production
Service Limit
Production
Service Limit
Production
Service Limit
Diameter
Production
Service Limit
Production
Service Limit
Production
Service Limit
Intake
Exhaust
Intake
Exhaust
L _
Intake
Exhaust
Intake
Exhaust
Intake
Exhaust
Closed
Open
± 1 /32"
Free Length
4.8 LITER L6 6A4-33
All
2.2979-2.2994
0.0002 (Maximum)
0.001 (Maximum)
0.0002 (Maximum)
0.001 (Maximum)
#1-#6: 0.0010-0.0024
#7: 0.0016-0.0035
#1-#6: 0.0010-0.0025
#7: 0.0015-0.0035
0.002-0.006
2.099-2.100
0.0005 (Maximum)
0.001 (Maximum)
0.0005 (Maximum)
0.001 (Maximum)
0.0010-0.0026
0.0030 (Maximum)
0.006-0.017
0.2315
0.2315
1.8677-1.8697
0.020 (Maximum)
0.003-0.008
Hydraulic
1.75:1
One Turn Down From Zero Lash
46°
46°
0.002 (Maximum)
0.035-0.060
0.062-0.093
0.0010-0.0027
0.0015-0.0032
High Limit Production +0.001
High Limit Production +0.002
2.08
78-86 lbs. @ 1.66"
170-180 lbs. @ 1.26"
1 21/32
1.94
4
B-07898