![background image](http://html1.mh-extra.com/html/gmc/s-series-1994/s-series-1994_repair-manual_2235929367.webp)
GENERAL DESCRIPTION
ENG INE CO NSTRUCTIO N
The 4.3L engine, RPO LB4 (VIN Z), is a liquid-cooled
90-degree V6 type with overhead valves, cast iron
block, and cylinder heads. 4.3L (VIN Z) engines used in
C/K/S/T vehicles have a cast-iron balance shaft mount
ed in the crankcase above and inline with the camshaft.
For engine identification, refer to SECTION OA. For
engine com ponent identification refer to figures 1
through 6.
CYLINDER BLOCK
The cylinder block has 6 cylinders arranged in a “V ”
shape with 3 cylinders in each bank. Starting at the
front of the engine, cylinders in the right bank are num
bered 1-3-5 and cylinders in the left bank are numbered
2-4-6 (when viewed from the front of the engine). The
firing order of the cylinders is 1-6-5-4-3-2. The cylinders
are encircled by coolant jackets.
CYLINDER HEADS
The cylinder heads have one intake and one exhaust
valve for each cylinder. A spark plug is located between
the valves in the side of the cylinder head. The valve
guides are integral and the rocker arms are retained on
individual threaded-in or pressed-in studs (depending
on where the engine was built).
CRANKSHAFT
The crankshaft is supported by four main bearing
inserts. The number four bearing at the rear of the
engine is the end thrust bearing. The bearings are
retained by bearing caps that are machined with the
block for proper alignment and clearances.
CAMSHAFT
The camshaft is supported by four full round, sleeve
type bearings. A sprocket on the crankshaft drives a
timing chain which in turn drives the camshaft through a
sprocket.
PISTONS AND CONNECTING RODS
The pistons are made of cast aluminum alloy using
two compression rings and one oil control ring. Piston
pins are offset 1.6 mm (1/16 inch) toward the major
thrust side (right-hand side) to reduce piston slap as the
connecting rod travels from one side of the piston to the
other side after a stroke. The pins are a press fit in the
connecting rod and a floating fit in the piston.
BALANCE SHAFT
S/T Vehicles and C/K Vehicles with light duty
emissions
The cast-iron balance shaft is mounted in the crank
case above and in line with the camshaft. A camshaft
gear drives the gear attached to the balance shaft. The
front end of the balance shaft is supported by a ball
bearing and the opposite end uses a sleeve bearing.
VALVE TRAIN
The valve train is a ball pivot type. Motion is transmit
ted from the camshaft through the hydraulic lifter and
pushrod to the rocker arm. The rocker arm pivots on its
ball and transmits the camshaft motion to the valve.
The hydraulic valve lifters with roller followers keep all
parts of the valve train in constant contact. Each lifter
acts as an automatic adjuster and maintains zero lash
in the valve train and eliminates the need for periodic
valve adjustment.
INTAKE MANIFOLD
A cast-iron intake m anifold is used that has an
exhaust gas recirculation (EGR) port cast into it for the
mixture of exhaust gases with the fuel and air mixture.
ENGINE LUBRICATION
Lubrication schematics are shown in figures 7 through
10. 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. Fil
tered oil flows into the main gallery and then to the
camshaft, balance shaft rear bearing (S/T vehicles), and
crankshaft bearings. The valve lifter oil gallery supplies
oil to the valve lifters. Oil flows from the hydraulic lifters
through the hollow pushrods to the rocker arms. Oil
from 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.
Summary of Contents for S Series 1994
Page 1: ......
Page 11: ...VIEW A p n n n j VIEW C F7554 Figure 10 Hydra Matic 4L60 E Transmission I D Location...
Page 24: ...NOTES...
Page 26: ......
Page 69: ...NOTES...
Page 71: ...3 2 STEERING...
Page 73: ......
Page 84: ......
Page 102: ...40...
Page 130: ...NOTES...
Page 146: ...NOTES...
Page 162: ...NOTES...
Page 166: ...Figure 5 Removing the Pinion Flange Figure 6 Pressing the Drive Pinion from the Cage...
Page 178: ...Figure 3 Spreading the Differential Case Figure 4 Removing the Differential...
Page 190: ...NOTES...
Page 202: ...NOTES...
Page 206: ...F5785...
Page 212: ...B Button Moved Out of Bearing Bore F5791...
Page 228: ...NOTES...
Page 232: ......
Page 234: ......
Page 236: ...Adjuster 63 Bolt 64 Lock Figure 10 Turning the Adjuster Plug K3 Models...
Page 237: ...Figure 13 Removing the Pinion Seal 39 Bearing Cup Figure 16 Removing the Inner Bearing Cap...
Page 261: ...F7475...
Page 267: ...B Button Moved Out of Bearing Bore F5791...
Page 294: ...NOTES...
Page 300: ...NOTES...
Page 318: ...NOTES...
Page 322: ...SR207LN2 EDS...
Page 324: ......
Page 326: ...OVERHEAD OILING AND RETURN MAIN OIL GALLERY N30005 6A2 J EDS...
Page 368: ...103 153 127 V1200...
Page 370: ......
Page 372: ......
Page 374: ...F9375 Figure 7 Engine Lubrication Diagram Engines Without Balance Shaft...
Page 376: ...Figure 9 Engine Lubrication Diagram Engines With Balance Shaft...
Page 399: ...V2974...
Page 410: ......
Page 412: ...195 196 201 174 252 163 165 164 244 3706r3924...
Page 452: ......
Page 454: ...163 164 V1202...
Page 456: ...20 21x 302 210 4 0 41 2 5 2 5 1 2 51 4 2 e3 54 3 9 252 252 S 255 255 25 6 256 209 V1196...
Page 458: ...100 1 8 4 185 183 177 v 75 201 3706r1204...
Page 460: ......
Page 510: ......
Page 512: ...V2131...
Page 514: ...110 106 106 103 90 93 89 88 87 86 v 7 7 7 7 j A _ 111 f t 2 a a s 53 49 L 47 46 3706r4751...
Page 516: ...259 260 150 237 S lM 180 167180 J 1 82 183 170 169 1 1 78 1 7 9 213212 2 0 7 205 r i 3706r4752...
Page 566: ...NOTES...
Page 574: ...NOTES...
Page 618: ...SPECIAL TOOLS...
Page 620: ...NOTES...
Page 672: ......
Page 682: ......
Page 686: ......
Page 694: ...RH0213 4L60 E...
Page 695: ...657 659 m i J 8092 H J 34196 4 3 34196 5 657 658 665 J 23907 J 7004 1 J 8092 RH0214 4L60 E...
Page 696: ...J 8092 J 34196 4 33 31 J 8092 RH0215 4L60 E...
Page 697: ...SPECIAL TOOLS...
Page 698: ...SPECIAL TOOLS...
Page 758: ...RH0194 4L80 E...
Page 764: ......
Page 770: ...SPECIAL TOOLS...
Page 771: ...SPECIAL TOOLS CONT...
Page 772: ......
Page 775: ......
Page 776: ......
Page 785: ......
Page 804: ...NOTES...
Page 806: ......
Page 808: ......
Page 822: ...3707r5079...
Page 840: ......
Page 848: ...NOTES...
Page 852: ......
Page 860: ...F5435...
Page 866: ......
Page 878: ...F9167...
Page 882: ...16 FrontOutputShaft 18 DrivtQNr 19 DrivenGm t 20 DriveChain 22 FrontOutputBearing V2836...
Page 890: ...F9168...
Page 908: ......
Page 919: ......