External View
External View
GENERAL
The V8 supercharged petrol engine is a 4.2 liter, 8 cylinder, 90° 'Enclosed' V unit, with 4 valves per cylinder, operated by two overhead camshafts per cylinder head. The engine emissions comply with ECD3 (European Commission Directive) and US Federal Tier2 Bin 8 legislative requirements and employs catalytic converters, electronic engine management control and positive crankcase ventilation to limit the emission of pollutants. The cooling system is a low volume, high velocity system. The Engine Control Module (ECM) controls the fuel injection system, the ignition system and the electric throttle.
The cylinder block is of aluminum alloy construction with cast iron liners. A cast aluminum bedplate is bolted to the bottom of the block to improve lower structure rigidity. The cylinder heads are cast aluminum with thermo-plastic camshaft covers. The single-piece oil sump is also cast aluminum. The fabricated stainless steel twin skin exhaust manifolds are unique for each cylinder bank. A molded plastic acoustic cover is fitted over the upper engine to reduce engine-generated noise.
Engine Structure
TECHNICAL FEATURES
The technical features include:
^ An eight-cylinder 90° 'Enclosed V configuration liquid cooled aluminum cylinder block with cast iron liners
^ Pistons are of open-ended skirt design, with two compression rings and a three-piece oil control ring
^ Two aluminum cylinder heads, each incorporating two camshafts manufactured in chilled cast iron
^ Four valves per cylinder
^ Graded valve lifters (shimless)
^ Belt driven supercharger
^ Top fed, 12-hole fuel injectors
^ Engine front cover manufactured from aluminum, accommodating the crankshaft front oil seal
^ Primary and secondary chain drive for the camshafts
^ An aluminum bedplate
^ A cast iron crankshaft
^ Fracture-split connecting rods in sintered-forged steel
^ A twin multi-vee belt, driving the front-end accessories
^ Fabricated stainless steel twin skin exhaust manifolds
^ An advanced engine management system incorporating electronic throttle control
^ Meets with the fault handling requirements, as detailed in the European On-Board Diagnostic (EOBD) III, US Federal OBD and California OBDII legislation.
ENGINE DATA
CYLINDER BLOCK COMPONENTS
Cylinder Block
The cylinder block is an 'Enclosed V design, which provides an inherently rigid structure with good vibration levels. A low volume coolant jacket improves warm-up times and piston noise levels, the longitudinal flow design of the jacket, with a single cylinder head coolant transfer port in each bank, improves rigidity and head gasket sealing. The right hand cylinder bank is designated as 'A' bank, and the left hand as 'B' bank. The cylinder bores are numbered from 1 to 4, for bank 'A' and 5 to 8 for bank 'B', starting from the front of the engine.
Piston Cooling Jets
Jets located in the cylinder block provide piston and gudgeon pin lubrication and cooling. These jets spray oil on the underside of the piston.
Lubrication oil is distributed through the cylinder block, via the main oil gallery and channels bored in the block, to all critical moving parts. These channels divert oil to the main and big-end bearings via holes machined into the crankshaft.
Engine Data Locations
Engine data is marked at three locations, two on the cylinder block (shown) and one on the engine front cover, which consists a label displaying the engine number. Component diameters are represented by alphabetical and numerical codes, keys to the codes are in the Service Repair Procedures.
Connecting Rods and Pistons
The connecting rods are manufactured from sinter-forged steel and have fracture-split bearing caps. The bearing caps are produced by fracturing the opposing sides of the connecting rod at the bearing horizontal center line. As well as being easier to manufacture, when reassembled the fractured surfaces interlock to form a strong seamless joint. The cylinder position is marked on adjoining sides of the joint to identify matching connecting rods and bearing caps. The connecting rod bearings are aluminum/tin split plain bearings.
The pistons are of the open-ended skirt design with a dished crown. They are also manufactured from a higher strength aluminum alloy and incorporate a thicker top land to resist the increased thermal and mechanical loads produced by supercharging. Three piston rings, two compression and one solid oil control ring, are installed on each piston. Each piston is installed on a gudgeon pin located in an bronze bushing in the connecting rod.
Connecting Rod and Piston Installation
The piston grade number is stamped on the crown of the piston and must coincide with that for each cylinder bore. The piston must be assembled in the correct orientation for the designated cylinder bore:
^ Bank 'A' - piston grade number and the thick flange of the connecting rod must face the front of the engine
^ Bank 'B' - piston grade number and the thin flange of the connecting rod must face the front of the engine
Crankshaft Position Sensor
The CKP sensor is installed at the rear of the sump. It is a variable reluctance sensor that provides an input of engine crankshaft speed and position.
Knock Sensors
The knock sensors are installed in the cylinder block on the inboard side of each cylinder bank. They are piezo-electric sensors that provide inputs to detect and locate detonation during combustion.
Starter
The engine starter motor is installed at the rear right side of the engine, at the cylinder block to bedplate split line.
Coolant Drain Plug/Heater
A coolant drain plug is installed on the rear left side of the cylinder block. On vehicles with the cold climate package, the cylinder block heater replaces the drain plug.
On vehicles destined for Canada, the coolant heater is installed during engine manufacture, but for Scandinavian vehicles the heater is supplied in kit form to be installed at the dealership.
Coolant Pump
The coolant pump is installed between the two cylinder banks, on the front face of the cylinder block.
Coolant Inlet and Outlet Assembly
To accommodate the installation of the supercharger, the thermostat housing and coolant outlet duct are combined into an aluminum alloy coolant outlet assembly, which is installed between the two cylinder banks, immediately above the coolant pump. A hose connects the coolant outlet assembly to a coolant inlet housing attached to the coolant pump intake on the cylinder block. The thermostat controls the flow of coolant through the radiator.
CRANKSHAFT AND SUMP COMPONENTS
Crankshaft and Main Bearings
Six counter-balance weights ensure good vibration levels from the four throw, five bearing crankshaft. Manufactured in cast iron, the crankshaft also has undercut and rolled fillets for improved strength.
The crankshaft rear oil seal is a press fit in the bedplate to cylinder block interface.
The main bearings are aluminum/tin split plain bearings. An oil groove in the upper half of each bearing transfers the oil into the crankshaft for lubrication of the connecting rod bearings. An aluminum/tin thrust washer is installed each side of the top half of the center main bearing.
Bedplate
The bedplate is a structural casting bolted to the bottom of the cylinder block to retain the crankshaft. The use of a bedplate further improves rigidity. Iron inserts, cast into the main bearing supports of the bedplate, minimize main bearing clearance changes due to heat expansion.
Two hollow dowels align the bedplate with the cylinder block.
Beads of sealant seal the joint between the bedplate and the cylinder block.
Sump
The aluminum alloy structural sump is bolted to the bedplate. A windage tray attached to the underside of the bedplate isolates the oil pan from the disturbed air produced by the rotation of the crankshaft, to prevent oil aeration and improve oil drainage. A rubber plug at the rear of the structural sump seals the port that provides access to the torque converter securing bolts. The engine oil drain plug is located at the front right corner of the oil pan.
A bead of sealant seals the joint between the structural sump and the bedplate.
Oil Pump
The oil pump is installed on the crankshaft at the front of the engine. The pump outlet port aligns with oil passages in the bedplate.
Starter Drive Plate
The starter drive plate is attached to the rear of the crankshaft. A timing disc, for the engine speed sensor, is spot welded to the front face of the drive plate.
Timing Disc
CAMSHAFT TIMING COMPONENTS
NOTE: Vehicles fitted with Variable valve timing.
Timing Gear
Multiple link primary and single row secondary chains drive the camshafts of each cylinder bank. The primary chains transmit drive from two sprockets on the crankshaft to each intake camshaft sprocket. The secondary chains transmit drive from the intake camshaft sprockets to the exhaust camshafts.
A key locates the two drive sprockets on the crankshaft. The crankshaft's torsional vibration damper retains the sprockets in position. The intake and exhaust camshaft sprockets are non-interference, non-keyed fit on their respective camshafts, the drive being transmitted by the face-to-face friction load produced by the sprocket-securing bolt.
Each chain has a hydraulic tensioner operated by engine oil. The primary chains are lubricated via oil squirt tubes located at the front of the engine block, near the crankshaft drive sprockets. A jet of oil from the end of each secondary chain tensioner lubricates the secondary chains. The primary chain tensioners act on pivoting flexible tensioner blades. The secondary chain tensioners act directly on the chains. Guide rails are installed on the drive side of the primary chains.
In certain markets some engines are equipped with VVT timing gear.
Timing Cover
The aluminum alloy timing cover accommodates the crankshaft front oil seal (a PTFE lip seal). Silicon rubber in-groove gaskets seal the joint between the timing cover and the front face of the engine.