GMC 1990 Light Truck Repair Manual page 415

A. Lubrication Begins
B. 189° Duration Of Lubrication
C End Of Lubrication
D. Lubrication Ends 154° BTDC
E. Cylinders 2, 4 And 6
F. 190° Duration Of Lubrication
G. Lubrication Ends 134° BTDC
H. For Cylinders 1, 3 And 5
J. Views Showing Intermittent Oiling Of
Connecting Rod Bearing Through Groove
On Upper Half Of Main Bearings
J
Figure 3—Engine Lubrication Diagram
2.8 LITER V 6A2-5
-6
B-09548