7.4L v8 - VIN [N] Chevrolet Cutaway P30

ENGINE IDENTIFICATION

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

Engine can be identified by eighth character of Vehicle Identification Number (VIN). VIN is stamped on a metal tag on top left end of instrument panel, near windshield. See ENGINE IDENTIFICATION table.

Engine can also be identified by engine identification (ID) number, stamped on front of cylinder block, immediately forward of right cylinder head or on left side of cylinder block, on engine-to-transmission mating flange.

ENGINE IDENTIFICATION CODES

VALVE CLEARANCE ADJUSTMENT

Note. Although valve clearance adjustment is not usually required (engine uses hydraulic valve lifters), perform the following procedures after servicing valve train.

1. Rotate engine until No. 1 piston is on TDC of compression stroke. Go to step 2) and adjust specified valves as listed in VALVE CLEARANCE ADJUSTMENT table.
2. Loosen rocker arm adjusting nut until lash is present. Tighten adjusting nut until lash is removed (under this condition, push rod cannot be rotated with fingers). Tighten adjusting nut 3/4 turn.
3. Rotate crankshaft 360 degrees to bring No. 6 piston to TDC of compression stroke. Adjust remaining valves. See VALVE CLEARANCE ADJUSTMENT table

VALVE CLEARANCE ADJUSTMENT

GENERAL PRECAUTION

Note. For reassembly reference, label all electrical connectors, vacuum hoses and fuel lines before removal. Also place mating marks on engine hood and other major assemblies before removal.

FUEL PRESSURE RELEASE

Disconnect battery terminals. Loosen fuel tank cap to relieve tank pressure. Internal constant bleed feature in throttle body injection unit relieves fuel system pressure when ignition switch is turned off. No further pressure relief is required.

ENGINE

Removal & Installation (Van)

1. Release fuel system pressure. See FUEL PRESSURE RELEASE. Disconnect battery. Remove engine cover. Drain crankcase and cooling system.
2. Remove air intake duct and air cleaner. Disconnect fuel lines, electrical connectors, vacuum hoses, coolant hoses and control cables as necessary. Remove distributor cap, distributor and ignition coil.
3. Remove transmission and engine oil dipstick tubes. Remove EGR purge valve. Remove 2 A/C compressor brackets. Remove throttle body injection unit. Remove headlight bezels, grille, bumper filler panel and cruise control servo (if equipped). Remove hood latch, coolant reservoir and upper radiator brackets.
4. Remove front end sheet metal cross panel. Discharge A/C refrigerant system. Remove A/C condenser, windshield washer fluid reservoir and washer pump. Remove upper fan shroud, engine oil cooler and transmission oil cooler. Remove radiator, lower fan shroud, fan, serpentine drive belt and water pump pulley.
5. Disconnect A/C refrigerant line from accumulator and alternator bracket. Remove A/C compressor and idler pulley. Remove alternator and belt tensioner. Remove exhaust crossover pipe from manifolds. Remove starter. Disconnect drive shaft and shift linkage from transmission.
6. Remove engine mount through-bolts. Support transmission. Remove transmission crossmember. Lower vehicle. Attach engine hoist. Remove engine and transmission as an assembly.
7. To install, reverse removal procedure. Fill crankcase and cooling system. Evacuate and charge A/C refrigerant system.

Removal & Installation ("P" Series: Parcel vehicle)

1. Release fuel system pressure. See FUEL PRESSURE RELEASE. Disconnect battery. Remove hood. Drain cooling system.
2. Remove air cleaner, accessory drive belt, fan and water pump pulley. Remove radiator and fan shroud. Disconnect heater hoses from engine. Disconnect fuel lines, electrical connectors, vacuum hoses, coolant hoses and control cables as necessary.
3. Remove A/C compressor and power steering pump with hoses attached and set aside (if equipped). Raise and support vehicle. Drain crankcase. Disconnect exhaust pipes from manifolds. Remove starter. Remove flywheel cover. Remove torque converter bolts (A/T).
4. Remove bellhousing bolts and engine mount through-bolts. Lower vehicle. Support transmission. Attach engine hoist. Remove engine. To install, reverse removal procedure. Fill crankcase and cooling system.

Removal

1. Release fuel system pressure. See FUEL PRESSURE RELEASE. Disconnect battery. Drain cooling system. Remove air cleaner.
2. Disconnect fuel lines, electrical connectors, vacuum hoses, coolant hoses and control cables as necessary. Remove alternator bracket, A/C compressor (with hoses attached), throttle body injection unit and cruise control servo as necessary.
3. Remove distributor cap. Mark distributor rotor in relation to distributor housing. Mark base of distributor housing in relation to intake manifold. Remove distributor. Remove intake manifold bolts, intake manifold and gaskets.

Installation

1. Install front and rear intake manifold seals on cylinder block. Install gaskets on cylinder heads. (Scheme 27)
2. Install intake manifold and bolts. Tighten bolts in sequence to specification. (Scheme 28) See TORQUE SPECIFICATIONS table. To complete installation, reverse removal procedure. Fill cooling system.

Scheme 27

Scheme 28

Remove heat stove tube. Remove all attached brackets and heat shields. If necessary, remove dip stick tube. Disconnect oxygen sensor electrical connector. Disconnect exhaust pipe from manifold. Remove exhaust manifold bolts and exhaust manifold.

Install manifold. Tighten bolts to specification. See TORQUE SPECIFICATIONS table. Bend over lock tabs (if equipped). To complete installation, reverse removal procedure.

CYLINDER HEAD

Note. The exhaust valve push rods are longer than the intake valve push rods.

1. Release fuel system pressure. See FUEL PRESSURE RELEASE. Remove intake manifold. See INTAKE MANIFOLD.
2. Remove exhaust manifold. See EXHAUST MANIFOLD. Remove valve covers. Loosen rocker arm nuts. Rotate rocker arms to side. Remove push rods and mark for reassembly to original locations. Remove cylinder head bolts. Remove cylinder head.

1. Clean gasket surfaces, bolt threads and bolt holes. If using steel head gasket, thinly coat both sides of gasket with sealant. DO NOT apply sealant to composition (steel/asbestos) head gaskets. Position head gasket on cylinder block. Ensure all holes align. Coat head bolt threads with Sealant (1052080).
2. Install cylinder head with bolts finger-tight. Tighten head bolts in sequence to specification. (Scheme 29) See TORQUE SPECIFICATIONS table. Lubricate valve tip, rocker arm pivot and push rod socket with Molykote.
3. To complete installation, reverse removal procedure. Adjust valves. See VALVE CLEARANCE ADJUSTMENT under ADJUSTMENTS.

Scheme 29

Remove accessory drive belt(s) and pulley. Remove crankshaft damper bolt. Using Damper Puller/Installer (J-23523-E), remove crankshaft damper. Carefully pry seal from cover with screwdriver. DO NOT distort front cover.

1. Coat seal lip with engine oil. Using Seal Installer (J-22102), install new seal in front cover with seal lip facing engine. Apply RTV sealant to Woodruff keyway in crankshaft damper.
2. Install crankshaft damper. Install crankshaft damper bolt and tighten to specification. See TORQUE SPECIFICATIONS table. To install remaining components, reverse removal procedure.

1. Disconnect battery. Drain cooling system. If necessary, remove radiator shroud. Remove accessory drive belts, fan and pulley. Remove crankshaft damper bolt. Using Damper Puller/Installer (J-23523-E), remove crankshaft damper.
2. Remove all mounting brackets and coolant hoses attached to water pump. Remove water pump. Remove oil pan. See OIL PAN. Remove front cover and gasket.
3. Rotate crankshaft until timing marks on camshaft and crankshaft sprockets are aligned. (Scheme 30) Remove camshaft sprocket and timing chain. To remove crankshaft sprocket, use Sprocket Puller (J-1619).

1. Install Woodruff key in crankshaft (if removed). Using Crankshaft Sprocket Installer (J-22102), install crankshaft sprocket. Install camshaft sprocket and timing chain, ensuring timing marks on sprockets are aligned. (Scheme 30)
2. Install and tighten camshaft sprocket bolts to specification. See TORQUE SPECIFICATIONS table. Install gasket to front cover with gasket sealant. Install front cover and gasket.
3. Apply RTV sealant to Woodruff keyway in crankshaft damper. Install crankshaft damper. Install crankshaft damper bolt and tighten to specification. See TORQUE SPECIFICATIONS table. To install remaining components, reverse removal procedure.

Scheme 30

VALVE LIFTERS

Note. The exhaust valve push rods are longer than the intake valve push rods.

1. Remove intake manifold. See INTAKE MANIFOLD. Remove valve covers. Loosen all rocker arm nuts and rotate rockers to one side.
2. Remove push rods, noting location for reassembly reference. Remove lifters, noting location for reassembly reference.

Coat lifter feet and body with High Viscosity Oil/Zinc (12345501). Install lifters in original location. To install remaining components, reverse removal procedure.

Remove radiator, A/C condenser (if equipped) and grille. Remove valve lifters. See VALVE LIFTERS. Remove timing chain and camshaft sprocket. See TIMING CHAIN & SPROCKETS. If necessary, raise engine. Remove camshaft.

Coat camshaft lobes and bearing journals with High Viscosity Oil/Zinc (12345501). Install camshaft. To install remaining components, reverse removal procedure.

Remove transmission, clutch (M/T) and flywheel. Using screwdriver, pry seal from housing. DO NOT scratch crankshaft sealing surface. Note direction of seal lip.

1. Lubricate inner and outer diameter of seal with engine oil. Place seal on Seal Installer (J-38841). Position seal installer against crankshaft.
2. Thread the attaching screws into crankshaft flange and tighten with screwdriver. This squares the seal with the crankshaft. Rotate seal installer handle until it bottoms. Remove seal installer. Install flywheel, clutch (M/T) and transmission.

Disconnect battery. Drain cooling system. Remove all drive belts, coolant hoses and mounting brackets attached to water pump. If necessary, remove fan shroud. Remove fan and pulley. Remove water pump and gaskets.

Install water pump with new gaskets. Tighten water pump bolts to specification. See TORQUE SPECIFICATIONS table. To install remaining components, reverse removal procedure.

OIL PAN

Removal (Van)

1. Disconnect battery. Remove engine cover. Raise and support vehicle. Drain crankcase. Disconnect front drive shaft from differential. Remove transmission. Remove fly- wheel and engine oil dipstick tube.
2. Remove front engine mount through-bolts. Raise engine enough to allow room for oil pan removal. Remove oil pan bolts (DO NOT remove oil pan). Remove oil pump and allow to rest in oil pan. Remove oil pump and oil pan. CAUTION: Disconnect oil pressure tube from side of engine to prevent damage to tube when engine is raised.

Removal ("P" Series: Parcel vehicle)

1. Disconnect battery. Disconnect oil pressure tube from side of engine. Raise and support vehicle. Drain crankcase. Remove strut rods and flywheel cover. Disconnect oil cooler lines from oil filter housing.
2. Disconnect vent hose from front differential (4WD). Remove starter. Remove front engine mount through-bolts. Raise and support engine. Remove oil pan bolts, oil pan and gasket.

Installation (Both Models)

1. Apply RTV sealant to both sides of oil pan gasket.
2. Install oil pan. Tighten oil pan bolts to specification. See TORQUE SPECIFICATIONS table. To install remaining components, reverse removal procedure. Fill crankcase.

OIL PUMP

Note. Pick-up tube and pump are serviced as an assembly.

Removal & Disassembly

1. Remove oil pan. See OIL PAN. Remove oil pump bolt. Remove pump and extension shaft.
2. Remove pump cover. Mark relationship between gears at a meshing point for reassembly. Remove gears. Remove pressure regulator valve retaining pin. Remove pressure regulator valve and spring.

Inspection

Inspect pump body and cover for cracks or excessive wear. Inspect pump gears for damage or wear. Check drive gear shaft for looseness in pump body. Check pressure regulator valve for fit in bore. Replace entire pump assembly if damaged. Inspect inlet tube and screen assembly for damage.

Reassembly & Installation

1. Install pump gears into pump body with marked gear teeth indexed. If pick-up tube was removed, apply sealant to tube end. Tap tube end into pump using plastic hammer. Reassemble remaining components in reverse order of disassembly.
2. Prime oil pump with engine oil. Install pump and extension shaft, ensuring slot on top of extension shaft engages with drive tang on end of distributor shaft. Tighten oil pump bolt to specification. See TORQUE SPECIFICATIONS table. Install oil pan.

VALVE SPRINGS

1. Measure valve spring free length, installed height and pressure (tension). Replace valve spring if not within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS.
2. Measure installed height between cylinder head spring seat (or top of shim, if shimmed) and top of spring. If installed height exceeds specification, install shims as necessary to bring installed height to specification. Ensure installed height is not less than specified.

VALVE STEM OIL SEALS

1. Intake and exhaust valves use lower umbrella seal.
2. When installing umbrella seal, seat the seal against valve guide boss on cylinder head. Coat upper "O" ring seal with engine oil before installation and ensure seal is not twisted when installed.

VALVE GUIDES

Valve guides are part of cylinder head (not replaceable). Measure valve guide oil clearance. See CYLINDER HEAD table under ENGINE SPECIFICATIONS. If not within specification, ream valve guide and install valves with oversize stems.

VALVES

Replace valve if margin is less than 1/32" (.8 mm).

ROCKER ARM ASSEMBLY

Clean push rods, rocker arms, balls and nuts with solvent and blow dry. Inspect rocker arms and balls at mating surface. The surface should be smooth and free of damage. Inspect push rods for bends or wear. Ensure oil passages are clear.

PISTON & ROD ASSEMBLY

1. Mark piston in relation to cylinder bore before removal. Piston pin is press-fitted in connecting rod. Mark piston in relation to connecting rod before separating components.
2. Replace piston and piston pin as matched set. Install piston in bore with dimple on top of piston toward front of engine.

FITTING PISTONS

1. Measure piston diameter at 90 degree angle to piston pin, on piston pin centerline. Measure cylinder bore diameter 2 1/2" below cylinder block deck. Determine piston clearance.
2. If piston clearance is not within specification, replace piston and/or machine cylinder bore as necessary. See CYLINDER BLOCK table and PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS.

PISTON RINGS

Measure piston ring end gap and side clearance. If not within specification, replace piston and/or rings as necessary. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS. Install rings with mark on ring facing upward. Position ring end gaps around circumference of piston as specified. (Scheme 31)

Scheme 31

ROD BEARINGS

1. Measure rod bearing journal out-of-round, taper and oil clearance. If not within specification, replace rod bearings and/or machine crankshaft. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.
2. Ensure rod side play is within specification. See CONNECTING RODS table under ENGINE SPECIFICATIONS. NOTE: If rear main bearing cap is removed, rear crankshaft oil seal must be replaced (transmission must be removed to replace seal).

CRANKSHAFT & MAIN BEARINGS

1. Mark bearing caps for reassembly. Measure journal diameter, out-of-round, taper and oil clearance. If not within specification, replace main bearings and/or machine crankshaft. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.
2. Align thrust bearing surfaces and measure crankshaft end play. See THRUST BEARING.

THRUST BEARING

1. Install main bearing caps (except rear) and tighten cap bolts to specification. See TORQUE SPECIFICATIONS table. Apply anaerobic sealant to cap-to-cylinder block mating surfaces. Install rear main bearing cap and tighten cap bolts to 10 ft. lbs. (14 N.m).
2. Tap crankshaft rearward then forward to align thrust surfaces. Tighten rear main bearing cap bolts to specification. Measure crankshaft end play at forward thrust surface of rear main bearing cap. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.

CYLINDER BLOCK

Measure cylinder bore out-of-round and taper. If not within specification, machine cylinder bore and/or replace piston. See CYLINDER BLOCK table under ENGINE SPECIFICATIONS.

DESCRIPTION

Gear-type oil pump delivers full pressure lubrication through full-flow oil filter to main oil gallery. Main oil gallery feeds crankshaft and camshaft bearings through drilled passages in block.

Valve lifter oil gallery feeds valve lifters. From lifters, oil is routed through hollow push rods to upper valve train components. Timing chain and sprockets are lubricated by oil drainage from No. 1 camshaft bearing. Pistons and piston pins are lubricated by oil splash. Non-adjustable oil pressure regulator is located in oil pump body.

CRANKCASE CAPACITY

See CRANKCASE CAPACITY table.

CRANKCASE CAPACITY (1)

OIL PRESSURE

Measure oil pressure with engine at operating temperature and specified RPM. See OIL PRESSURE SPECIFICATIONS table.

OIL PRESSURE SPECIFICATIONS (1)

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

BEARING SPECIFICATIONS

MAIN & CONNECTING ROD BEARINGS SPECIFICATIONS

CONNECTING ROD SPECIFICATIONS

CONNECTING ROD SPECIFICATIONS

PISTON/PIN/RING SPECIFICATIONS

PISTONS, PINS & RINGS SPECIFICATIONS

CYLINDER BLOCK SPECIFICATIONS

CYLINDER BLOCK SPECIFICATIONS

VALVE/VALVE SPRING SPECIFICATIONS

VALVES & VALVE SPRINGS SPECIFICATIONS

CYLINDER HEAD SPECIFICATIONS

CYLINDER HEAD SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

See also:
• ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION