Subject Page; Description; Engine Lubrication - GMC 1990 Light Truck Repair Manual

A 2.8 LITER V
6 2 - 2
SUBJECT
Assembly of Engine (Continued)
Torsional Damper Installation.................................................................................................................................6A2-21
Piston and Connecting Rod Installation.............................................................................................................. 6A2-22
Oil Pump Installation............................................................................................................................................... 6A2-23
Oil Pan Installation................................................................................................................................................... 6A2-23
Cylinder Head Installation.......................................................................................................................................6A2-23
Valve Train Component Installation...................................................................................................................... 6A2-24
Valve Adjustment..................................................................................................................................................... 6A2-25
Intake Manifold Installation.....................................................................................................................................6A2-25
Rocker Arm Cover Installation...............................................................................................................................6A2-25
Exhaust Manifold Installation.................................................................................................................................6A2-26
EGR Valve Installation............................................................................................................................................. 6A2-26
Air Injection Tube Installation.................................................................................................................................6A2-27
Flywheel Installation............................................................................................................................................... 6A2-27
Engine Accessory Installation...............................................................................................................................6A2-27
Engine Set-Up and Testing.....................................................................................................................................6A2-27
Specifications..............................................................................................................................................................6A2-28
Special Tools................................................................................................................................................................6A2-31
GM 2.8L engines are 60-degree V6 type, overhead
valve, water cooled, with cast iron block and heads.
The crankshaft is supported by four precision insert
main bearings, with crankshaft thrust taken at the number
three bearing.
The camshaft is supported by four plain type bearings
and is chain driven. Motion from the camshaft is transmit­
ted to the valves by hydraulic lifters, pushrods, and ball
type rocker arms. The valve guides are integral in the cyl­
inder head.
The connecting rods are forged steel, with precision in­
sert type crankpin bearings. The piston pins are a press fit
in the connecting rods.
The pistons are cast aluminum alloy. The piston pins
are a floating fit in the piston.
For Engine Identification, refer to GENERAL INFORMA­
TION (SEC. OA) in this manual.
-6
CONTENTS (CONTINUED)

DESCRIPTION

ENGINE LUBRICATION

Lubrication schematics are shown in figures 1 through
4. The gear type oil pump is driven from the distributor
shaft, which is gear driven from the camshaft. Oil is drawn
into the oil pump through a pickup screen and pipe.
Pressurized oil is routed to the oil filter. In case of
excessive oil pressure, a bypass valve is provided. From
the filter, oil is routed to the main oil gallery which supplies
the left bank valve lifters with oil. From the left gallery, oil
is directed to the camshaft bearings and the right oil
gallery.
Oil flows from the hydraulic lifters through the hollow
pushrods to the rocker arms. Oil from the overhead drains
back to the crankcase through oil drain holes.
The timing chain is drip fed from the front camshaft
bearing. The pistons and piston pins are lubricated by oil
splash.
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