2.8l v6 - VIN [b] Chevrolet Cab & Chassis C20

ENGINE IDENTIFICATION

Note. For engine repair procedures not covered in this article, see ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION article in the GENERAL INFORMATION section.

The engine identification number is stamped on a machined pad on front of cylinder block, just rearward of engine front cover. The Vehicle Identification Number (VIN) is located on the left side of the dash panel at the base of the windshield. The eighth character of the (VIN) denotes engine type.

ENGINE IDENTIFICATION CODES

Valve Arrangement

1. Left Bank - E-I-I-E-I-E (Front-to-rear).
2. Right Bank - E-I-E-I-I-E (Front-to-rear).

Note. Tighten adjusting nut 1 1/2 turns after lash is eliminated.

1. Adjust valves by backing off adjusting nut until lash (play) is felt at push rod. Then tighten nut until all lash is removed. Tighten adjusting nut an additional 1 1/2 turns. (Scheme 32)
2. Rotate crankshaft to bring No. 1 piston at TDC on end of compression stroke. Adjust valves as listed in table.
3. Rotate crankshaft 360° to bring No. 4 piston at TDC on end of compression stroke. Adjust remaining valves. Install rocker arm covers. Check timing and idle speed.

VALVE CLEARANCE ADJUSTMENT

Valve Clearance Adjustment. Scheme 32

TROUBLE SHOOTING

Note. To trouble shoot engine mechanical components, see appropriate table in TROUBLE SHOOTING article in GENERAL INFORMATION.

ENGINE

See ENGINE REMOVAL article in the ENGINE section.

Removal

1. Disconnect battery negative cable. Remove air cleaner. Drain cooling system. Label and disconnect all electrical connectors, vacuum hoses and emissions hoses at distributor, carburetor and intake manifold.
2. Disconnect fuel line at carburetor. Disconnect spark plug wires at spark plugs. Remove distributor cap and mark position of rotor. Remove distributor.
3. Remove all brackets attached to rocker arm covers, and remove covers. Remove upper radiator hose and heater hose from engine. Remove A/C drive belt and rotate compressor aside. Remove intake manifold and discard gaskets.

Scheme 33

1. Clean all gasket mating surfaces. Apply 3/16" bead of silicone sealant to front and rear sealing ridges of cylinder block. Install new intake manifold side gaskets onto cylinder heads. Gaskets are stamped "Left Side" and "Right Side".
2. Hold gaskets in place by extending silicone sealant bead 1/4" onto ends of side gaskets. New side gaskets will need to be cut to install behind push rods. (Scheme 33) (Scheme 33): Intake Manifold Gasket NOTE: Tighten bolts and nuts to 13-25 ft. lbs. (18-34 N.m).
3. Install intake manifold. Ensure sealing areas between cylinder ridges and ends of manifold are completely sealed. Install and tighten manifold attaching bolts and nuts. (Scheme 34) To complete installation, reverse removal procedure.

Intake Manifold Tightening Sequence. Scheme 34

Disconnect negative battery cable. Raise vehicle and disconnect exhaust pipes. On left side, remove 4 rear manifold bolts and 1 nut. Lower vehicle. On both sides, disconnect air diverter valve, hoses and wires. Remove power steering bracket. Remove manifold bolts and manifold.

Installation

To install, clean manifold-to-head mating surfaces and reverse removal procedure.

1. Remove intake manifold as previously described. Raise vehicle and disconnect exhaust pipes at manifolds. Drain coolant from block. Remove oil dipstick tube attachment. Lower vehicle and loosen rocker arm nuts and rotate rockers to side.
2. Remove push rods in sequence for reinstallation in original locations. Remove alternator, power steering pump, A/C compressor, and respective mounting brackets for these components. Position assemblies aside. Remove cylinder heads.

Scheme 35

1. Clean all gasket mating surfaces. Clean head bolt and cylinder block threads. Head gaskets are marked "This Side Up". Properly install gaskets in place on cylinder block. Install cylinder heads. Apply sealant to head bolt threads and install bolts. Tighten bolts in sequence. (Scheme 35) (Scheme 35): Cylinder Head Tightening Sequence
2. Coat rocker arm balls and rocker arm mating surfaces with assembly lubricant before installing. To complete installation, reverse removal procedure. Adjust valves.

ROCKER ARM STUDS

Replace damaged rocker arm studs with new studs. If threads in head are damaged, the head can be retapped and a helical insert installed. If a helical insert is not available, replace cylinder head.

1. Remove rocker arm cover, spark plug, rocker arm and push rod of cylinder to be serviced. Install air hose and adapter to spark plug hole and apply air pressure. DO NOT remove air pressure until components have been reassembled.
2. Using a valve spring compressor, compress valve spring and remove valve retainer locks and oil seal. Release compressor and remove retainer (or rotator), oil shield (exhaust only), and valve spring damper. On intake valves, remove teflon oil seal. (Scheme 36)

Intake and Exhaust Valve Assemblies. Scheme 36

Inspection

Using valve spring tester, check valve spring tension. Springs (without dampers) should test to within 10 lbs. of specification. Replace spring if not within limits.

1. Position valve spring and damper on cylinder head. Install teflon oil seal (intake only) in place over valve stem. Position oil shield (exhaust only) and retainer (or rotator) on valve spring.
2. Coat "O" ring type seal and valve stem with engine oil. Compress spring and install seal in lower groove of valve stem. Ensure seal is not twisted in groove. Install retainer locks and release compressor. Ensure retainer locks are properly seated in upper groove of valve stem.

VALVE SPRING INSTALLED HEIGHT

Installed height of valve springs should be 1.58" (40 mm). For intake valves, measure from top of spring damper tabs to bottom of retainer. For exhaust valves, measure from top of spring damper tabs to where top of valve spring contacts inside bottom of oil shield. If measurement exceeds specified height, install a.030" (.76 mm) shim at spring seat. (Scheme 37)

Checking Valve Spring Installed Height. Scheme 37

VALVE GUIDE SERVICING

If valve stem-to-guide clearance exceeds specifications, ream valve guide to proper oversize. Valves are available with .0035" (.089 mm), .0155" (.394 mm) and .0305" (.775 mm) oversize stems.

HYDRAULIC VALVE LIFTERS

If lifters are removed, ensure they are installed in original locations. Service lifters as complete assemblies only. If lifters are disassembled for cleaning and inspection, they should be reassembled and tested in a lifter leak-down rate tester. (Scheme 38)

Hydraulic Lifter Assembly. Scheme 38

Some engines may have both standard and.010" (.25 mm) oversize valve lifters. Engines with oversize lifters will be marked with a dab of White paint and "0.25 O.S." stamped on lifter boss. (Scheme 39)

Identifying Oversize Lifters. Scheme 39

Disconnect negative battery cable. Remove all drive belts, drain cooling system and remove water pump. If equipped, remove A/C compressor and mounting bracket. Remove vibration damper. Disconnect radiator lower hose at front cover and heater hose at water pump. Remove front cover.

Note. Install and tighten front cover and water pump before sealant sets up.

1. Clean sealing surfaces thoroughly. Apply 3/32" bead of RTV sealant to front cover-to-block sealing surface. Apply 1/8" bead silicone sealant to bottom of front cover sealing surface. (Scheme 40)
2. Place front cover on engine and install stud bolt and 2 lower bolts. Coat water pump bolts with pipe thread sealant. Apply 3/32" bead RTV sealant to water pump sealing surface, and install water pump and attaching bolts. To complete installation, reverse removal procedure.

Front Cover Sealant Application. Scheme 40

Oil seal may be replaced with front cover installed. Remove vibration damper. Using large screwdriver, pry seal out of cover. Use care not to damage crankshaft sealing area or front cover.

Install new seal with open side of seal toward inside of front cover. Use Seal Installer (J-23042) to drive seal into position. Install vibration damper.

1. Remove front cover. Rotate crankshaft to position No. 4 piston at TDC on end of compression stroke. Timing marks on camshaft and crankshaft sprockets should be aligned. No. 1 piston will be at TDC on end of exhaust stroke. (Scheme 41)
2. Remove camshaft sprocket bolts, then remove sprocket and chain. DO NOT allow camshaft or crankshaft to turn.

Install timing chain and camshaft sprocket. Timing marks must be aligned. (Scheme 41) Use attaching bolts to draw sprocket onto camshaft and tighten bolts. Lubricate chain with engine oil. Install remaining components in reverse order of removal.

Aligning Timing Sprockets. Scheme 41

With engine removed from vehicle, remove front cover and intake manifold. Remove rocker arm assemblies, push rods and valve lifters in sequence, for reinstallation in original locations. Remove fuel pump and push rod. Remove timing chain and sprocket. Remove camshaft, using care not to damage camshaft bearings.

Lubricate journals with engine oil and apply assembly lubricant to camshaft lobes. Carefully install camshaft. Prior to installing rocker arm assemblies, coat rocker arm ball and mating rocker arm surface with assembly lubricant. To complete installation, reverse removal procedure.

CAM LOBE LIFT

1. Remove rocker arm assemblies. Mount dial indicator on rocker arm stud. Position dial indicator and ball socket adapter on push rod.
2. Slowly rotate engine clockwise until lifter is on base circle of camshaft. Zero dial indicator. Rotate engine until push rod is fully raised. Record lobe lift reading and compare with specifications. If not within limits, replace camshaft and lifters.

Remove engine from vehicle. Remove camshaft. Ensure rod and main bearing caps are marked, and remove all caps. Push pistons to top of bores. Remove crankshaft. Remove camshaft rear cover from cylinder block. Using a camshaft bearing remover/installer remove camshaft bearings.

Using bearing remover/installer, install front and rear bearings first. These act as guides for the remover/installer and center the remaining bearings being pulled into place. Ensure bearing oil holes line up with oil gallery holes in block. To complete installation, reverse removal procedure.

OIL PAN

See OIL PAN REMOVAL article in the ENGINE section.

1. Remove oil pan, oil pump and cylinder heads. Place piston at bottom of stroke and cover piston with a cloth to collect cuttings. Use a ridge reamer to remove any ridge or deposits from upper portion of the cylinder bore.
2. If necessary, mark connecting rod and cap for reinstallation in original location. Remove connecting rod cap and install rubber hose over rod bolts. Push piston and rod out top of bore. Install cap to its respective connecting rod.

1. Install rings on the piston, and position the ring gaps. (Scheme 44) Insert oil ring spacer tang in piston oil hole (or slot). Hole is within arc of oil ring spacer gap "A". Apply a light coat of engine oil to piston, rings and cylinder bore. Using ring compressor, compress piston rings. Ensure ring gaps do not change during compressor installation.
2. Cover rod bolts with protective rubber hose. Install piston with notch (or machined hole) in piston head, toward front of engine. Rod bearing tang slot must be positioned away from camshaft. Remove rubber hose from rod bolts. With rod bearings installed, install and tighten rod caps.

Using an arbor press and piston pin remover/installer, press pin from piston and connecting rod.

Check clearance of pin in piston. Replace piston and pin assembly if not within limits. Lubricate piston and connecting rod pin bores. Assemble connecting rod to piston. Using piston pin remover/installer and an arbor press, press piston into place. Check piston for freedom of movement on pin.

Scheme 42

Scheme 43

1. Remove oil pan, oil pump and rear main bearing cap. Remove upper and lower rope seal, loosening Nos. 2 and 3 main bearing bolts if necessary. Clean seal channel.
2. Apply a thin coat of gasket sealer to outside of rubber seal, keeping sealer off seal lips. Roll seal into position in cylinder block. Use a piece of shim stock to slip between seal and block to prevent seal damage. Turn crankshaft to ease installation. Seal lip must face front of engine and seal dust lip must face flywheel. (Scheme 42) (Scheme 42): Cross Section of Rear Main Seal
3. Apply gasket sealer to other half of seal and install in rear main bearing cap. Apply a 1/32" bead of anaerobic sealer to cap between rear main seal end and oil pan rear seal groove. Keep sealer off rear seal, bearing and drain slot. (Scheme 43) (Scheme 43): Applying Sealer to Rear Main Bearing Cap
4. Apply light coat of engine oil to crankshaft surface at seal. Install rear main bearing cap. Tighten bearing cap bolts. Use Plastigage method to check bearings. Install oil pump and pan.

Disconnect battery negative cable. Drain cooling system. Remove heater hose from water pump. Remove water pump.

Apply 3/32" bead of anaerobic sealer to water pump sealing surface. Coat bolt threads with pipe thread sealer. Install and tighten water pump. Install remaining components in reverse order of removal.

Note. For further information on cooling system capacities and other cooling system components, see ENGINE COOLING SYSTEMS article.

FITTING PISTONS

1. Using telescopic gauge and micrometer, measure cylinder bore diameter. Measure piston diameter across piston skirt, at center of piston pin. Difference between 2 measurements is piston-to-cylinder clearance.
2. Using cylinder bore gauge, measure cylinder bore taper by working gauge up and down in bore. Difference between high and low readings is taper. Taper must not exceed .004" (.10 mm).
3. Measure cylinder bore out-of-round. Take out-of-round measurements at different points in bore, by rotating gauge horizontally, around entire circumference of bore. Out-of-round must not exceed .004" (.10 mm).
4. If taper or out-of-round are not within limits, rebore cylinders. Replacement pistons are available in standard, .020" (.50 mm) and .040" (1.0 mm) oversizes. When reboring cylinders, all main bearing caps must be installed and tightened.

FITTING RINGS

1. Position ring at bottom of cylinder bore, about 1/4" above ring travel. Ring must be square in bore. Measure ring end gap with a feeler gauge.
2. Before installing compression rings on pistons, check side clearance. Insert outer edge of ring in its respective groove, and slide ring around entire circumference of groove. The ring should slide freely in groove. If ring grooves have high steps on lower lands, piston must be replaced.
3. Check side clearance of compression rings, with feeler gauge inserted between ring and ring groove. Install and properly space rings on piston. Ensure oil ring spacer ends are butted, and not overlapped. Note that oil ring spacer anti-rotation tang is inserted into oil hole (or slot) of piston. (Scheme 44)

Desired Ring Gap Locations. Scheme 44

CONNECTING ROD BEARINGS

Note. This engine uses precision bearings, and shimming is not acceptable for adjustment. Never file or grind connecting rods or caps when fitting bearings.

1. Remove rod cap and use Plastigage method to check bearing clearance. With crank pin and bearing clean, place Plastigage across full width of bearing, about 1/4" off center and away from oil holes. Install and tighten rod cap. DO NOT let crankshaft turn.
2. Remove rod cap and determine clearance by measuring width of compressed Plastigage at widest point. If clearance is excessive, select a new undersize bearing and remeasure clearance.
3. Clean crankshaft journal and bearing seat in rod and cap. Insert bearings in rod and cap, then coat bearings with engine oil. Pull piston and rod assembly down onto crankshaft. Install and tighten rod cap. After all rods are installed, check side play between rod cap and crank pin thrust face.
4. Replacement bearings are available in standard, .0005" (.013 mm) and .0010" (.026 mm) undersizes for use with standard size crankshaft.

MAIN BEARINGS

Note. This engine uses precision bearings, and shimming is not acceptable for adjustment. Never file or grind connecting rods or caps when fitting bearings.

1. Use Plastigage method to check bearings. If engine is in vehicle, crankshaft must be supported at front and rear. Ensure that all bearing caps, other than the one being checked, are tightened to specifications. When checking No. 1 main bearing, remove all drive belts from crankshaft pulley.
2. Start with rear main bearing cap and work forward. New bearings are available in standard, .0006" (.016 mm) and .0012" (.032 mm) undersizes, for use with standard size crankshaft. Always replace both upper and lower bearing halves together.
3. Remove main bearings from cylinder block using bearing remover/installer. Insert remover/installer in crankshaft oil hole and rotate crankshaft clockwise. If remover/installer is unavailable, use a bent cotter pin.
4. Lubricate journal and bearing. Insert plain end of new bearing between crankshaft and notched side of block. Insert bearing remover/installer into crankshaft oil hole. Rotate crankshaft counterclockwise to install bearing into place.
5. Install lower bearing half into cap, then lubricate with engine oil. Install and tighten main bearing cap with arrow pointing toward front of engine.

THRUST BEARING ALIGNMENT

1. Ensure all main bearing caps, except No. 3, are installed and tightened. Tighten No. 3 thrust bearing cap bolts to 11 ft. lbs. (15 N.m).
2. Tap end of crankshaft rearward, then forward, to line up main bearing and crankshaft thrust surfaces. Tighten thrust bearing cap. Retighten all main bearing cap bolts, including thrust bearing. Rotate crankshaft to ensure there is no excessive drag.

CRANKSHAFT END PLAY

Check crankshaft end play after aligning thrust bearing. Pry crankshaft forward and insert feeler gauge between crankshaft counterweight and No. 3 main bearing cap forward face. End play should be .002-.008" (.06-.21 mm).

CRANKCASE CAPACITY

Crankcase capacity is 4.5 quarts (4.2L) with oil filter replacement.

NORMAL OIL PRESSURE

Normal oil pressure should be 30-50 psi (2.1-3.5 kg/cm 2 ) at speeds of 35-40 MPH with engine at operating temperature.

OIL PRESSURE REGULATOR VALVE

Oil pressure regulator valve is located in oil pump body. Valve is nonadjustable.

ENGINE OILING SYSTEM

The left main oil gallery (along upper left side of camshaft) supplies oil to the left bank hydraulic lifters. The left gallery directs oil to the camshaft bearings, crankshaft and right oil gallery.

The right oil gallery supplies oil to the right side hydraulic lifters. From valve lifters, oil is supplied to upper valve train through hollow push rods. All other components are lubricated by splash or nozzle method.

With engine removed from vehicle, remove oil pan. Remove bolt attaching oil pump to rear main bearing cap, then remove oil pump with extension shaft.

Disassembly

1. Remove pump cover. Mark gears at a meshing point, so they may be reassembled with same gear teeth indexing. Remove idler gear and drive gear and shaft from pump body.
2. Remove pressure regulator valve retaining pin, valve and spring. Remove oil inlet tube from body, if it needs replacement. DO NOT remove screen on oil inlet tube.

Note. If pump gears or body are damaged or worn, the entire pump assembly must be replaced.

Wash all parts and dry with compressed air. Inspect pump body, pump cover and pump gears for damage or excessive wear. Check drive gear shaft for looseness in pump body. Inspect oil inlet tube and screen for damage. Check pressure regulator valve for fit in bore.

Reassembly

1. If removed, install oil inlet tube and screen. Apply sealer to end of tube, and tap tube into place, using plastic hammer. Install pressure regulator valve, spring and retaining pin.
2. Install idler gear and drive gear and shaft into pump body. Ensure gear teeth previously marked are indexing. Install pump cover.

Prime oil pump. Assemble pump and extension shaft (with retainer) to rear main bearing cap. Ensure top end of hexagon extension shaft engages with hexagon socket of distributor drive gear. Install and tighten oil pump attaching bolt.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

VALVE SPECIFICATIONS

VALVE SPECIFICATIONS

PISTON/PIN/RING SPECIFICATIONS

PISTONS, PINS & RINGS SPECIFICATIONS

BEARING SPECIFICATIONS

CRANKSHAFT MAIN & CONNECTING ROD BEARINGS SPECS

VALVE SPRING SPECIFICATIONS

VALVE SPRINGS SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

See also:
• ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION