Engine - TDV8 3.6L Diesel (G938499)

Loading...

The TdV8 engine is a 3.6 liter, direct injection, 8-cylinder diesel engine having 2 banks of 4 cylinders, arranged at 90 degrees to each other. There are 4 valves per cylinder, which are operated by 2 overhead camshafts per cylinder.

DIN standard cylinder firing order 1,5,4,2,6,3,7,8

The engine emissions comply with ECD4 (European Commission Directive) legislative requirements and employs 2 catalytic converters systems, electronic engine management control, positive crankcase ventilation and exhaust gas recirculation to limit the emission of pollutants. The unit is water cooled and turbo-charged. The fuel injection system features common rail technology.

The cylinder block is manufactured in Compacted Graphite Iron (CGI) and is coupled with a separate cast aluminium oil pan to provide a lightweight, compact and very stiff bottom end. The cylinder heads are cast aluminium with a moulded plastic camshaft cover. The cast iron exhaust manifolds are unique for each cylinder and a moulded plastic acoustic cover is fitted over the upper engine to reduce engine-generated noise.

Technical Features

• 90 degree 'vee' 8 cylinder engine with a CGI cylinder block
• Plastic cylinder head cover
• Two light, high strength, aluminium cylinder heads
• Four-valve technology with centrally arranged fuel injectors
• Steel roller rockers with hydraulic lash adjusters
• Twin plenum intake system integrated with the camshaft cover
• Twin electronically controlled Variable Geometry Turbochargers (VGT)
• Common rail direct fuel injection system
• High pressure fuel pump
• Gallery cooled pistons with a central crown bowl
• Two electronically controlled Exhaust Gas Recirculation (EGR) valves
• Two EGR coolers
• Exhaust re-treatment by means of a diesel specific oxidation catalytic converter and primary catalytic converter
• Cooling fan with electro-viscous clutch drive

Cylinder Block

The cylinders and crankcase are contained in the closed-deck cylinder block, which is of single cast CGI construction with a hollow beam structure and features fully cross-bolted main bearing journals. With this type of construction less material is required than for a conventional cast iron block, therefore, reducing engine weight and length.

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.

A single connection at the Right Hand (RH) rear of the oil filter and oil/fuel cooler assembly connects a pipe to each of the turbochargers via a T-piece connector. Oil is supplied, under pressure via this connection, from the oil pump to provide lubrication for the turbochargers bearings.

Cylinder cooling is achieved by coolant circulating through chambers in the cylinder block casting.

Two hollow metal dowels are used to locate the cylinder heads to the cylinder block, one on each side at the rear of the unit.

A port is included at the rear RH and Left Hand (LH) side of the oil pan, below the turbochargers, to connect the turbochargers oil return pipes to a dedicated oil pan within the main oil pan (see 'Turbocharger Oil Return' section for more information).

A plug sealing the lubrication cross-drilling gallery is located at the front RH side of the cylinder block. Plugs for the main lubrication gallery are included at the front and rear of the cylinder block.

Piston Cooling Jets

Jets located in the cylinder block provide piston and gudgeon pin lubrication and cooling. These jets spray oil on to the inside of the piston. The oil then flows through 2 internal wave shaped channels to help cool each piston crown.

Crankshaft Position (CKP) Sensor

The Crankshaft Position (CKP) sensor is located at the rear of the crankshaft, behind the flywheel in the LH side of the rear oil seal retainer. The sensor provides an input of engine crankshaft speed and position. The sensor works on the Hall effect principle and scans a trigger wheel (magnetic disc) on the crankshaft. An air gap of 0.4 to 1.5mm, between the trigger wheel and the CKP sensor, is achieved by the positional mounting of the sensor. For additional information, refer to: Electronic Engine Controls (303-14D Electronic Engine Controls - TDV8 3.6L Diesel, Description and Operation).

Knock Sensors

Four knock sensors are located on the cylinder block between the 'vee' of each cylinder. The knock sensors produce a voltage signal in proportion to the amount of mechanical vibration generated at each ignition point. Each sensor monitors 2 cylinders in the related cylinder bank.

The signals are supplied to the Engine Control Module (ECM), which compares them with mapped signals stored in it's memory. From this, the ECM can determine when detonation occurs on individual cylinders. For additional information, refer to: Electronic Engine Controls (303-14D Electronic Engine Controls - TDV8 3.6L Diesel, Description and Operation).

Starter Motor

The engine starter motor is installed at the rear RH side of the oil pan, at the cylinder block to oil pan split line. For additional information, refer to: Starting System (303-06D, Description and Operation).

Coolant Drain Plug

Two coolant drain plugs are installed in the cylinder block, 1 is fitted in the rear RH side, and the other is fitted in the middle of the cylinder block on the LH side.

Coolant Pump

The coolant pump is installed on center of the cylinder block front face and is secured and sealed using 4 bolts and an 'O' ring. A poly-vee belt drives the coolant pump via the crankshaft.

Oil Filter and Oil/Fuel Cooler Assembly

The oil filter and oil/fuel cooler assembly is located on the top of the cylinder block in the centre of the 'vee'. The oil filter is a replaceable cartridge installed on an adapter. For more information refer to the lubrication section.

Thermostat Assembly

The thermostat assembly connects the cooling channels of the cylinder block to the cooling channels of the LH and RH cylinder heads and provides the coolant outlet for the EGR and coolant return. For additional information, refer to: Engine Cooling (303-03B Engine Cooling - V8 N/A 4.4L Petrol, Description and Operation).

Crankshaft and Main Bearings

The crankshaft is forged steel and undercut rolled with induction hardened journals, which run in 5 main bearings.

The main bearing caps are double and cross-bolted, this adds to the strength and rigidity of the engine block.

The crankshaft drive pulley is not keyed onto the crankshaft; it is secured to the crankshaft by a single bolt.

The main bearings are aluminium/tin split plain selective bearings. An oil groove in the top half of each bearing transfers oil into the crankshaft for lubrication of the connecting rod bearings. The upper and lower shells of bearing number 5 contain integral thrust washers, which limits the crankshaft end float.

The crankshaft front oil seal is a press fit into the oil pump housing and requires a special tool for fitment.

The crankshaft rear oil seal is a press fit in the rear oil seal retainer. The rear oil seal retainer also houses the CKP sensor.

The trigger wheel is located on the rear of the crankshaft. It is pressed onto the crankshaft using a special tool, which also precisely aligns the trigger wheel for crankshaft position and timing. The trigger wheel consists of 60 magnets, minus 2 for ECM crankshaft position reference and synchronisation. The magnets cannot be seen on the trigger-wheel; therefore, it can only be positioned using the special tool. For additional information, refer to: Electronic Engine Controls (303-14D Electronic Engine Controls - TDV8 3.6L Diesel, Description and Operation).

The CKP sensor air gap is not adjustable. The sensor bolts into the rear oil seal retainer and the tolerance on the retainer and sensor give an air gap within the specified range.

Connecting Rods and Pistons

The connecting rods are manufactured from sinter-forged steel and have fracture-split bearing caps. Fracturing the opposing sides of the connecting rod at the bearing horizontal centerline produces the bearing caps. As well as being easier to manufacture, when reassembled the fractured surfaces interlock to form a strong seamless joint. The cylinder position is etched on adjoining sides of the joint to identify matching connecting rods and bearing caps. The selective connecting rod bearings are aluminium/tin split plain bearings. The connecting rod bearing is 'Bismuth coated' (Bismuth exhibits the greatest opposition to being magnetised and has one of the lowest thermal conductivity of all metals).

When installing a connecting rod, ensure the back of the connecting rod faces the center of the 'vee'.

The pistons are made from aluminium alloy and are fitted with 2 compression rings and an oil control ring. The piston crown incorporates a pronounced bowl; this forms the combustion chamber, which promotes swirl and turbulence necessary for good combustion and improved emissions. In addition, the piston skirt has a molybdenum-coated surface, which counteracts scoring of the cylinder bore and piston.

The piston also incorporates a double wave gallery within the piston crown to enhance piston cooling. The pistons are supplied oil by means of spray jets located in the cylinder block oil gallery. These jets ensure optimum piston cooling to counteract the high temperatures generated by the combustion process.

Each piston is installed on a wrist pin located in an aluminium/tin bushing in the connecting rod.

When installing pistons ensure the arrows on the piston crowns all point to the front of the engine.

The piston top ring is a taper type and is fitted with the taper to the top of the piston. All rings marked 'top' are assembled with 'top' uppermost. All rings must be spaced evenly around the piston before installing. The circumference gap of the double bevelled oil control ring must be opposite the spiral control joint.

Oil Pan

The cast aluminium oil pan is heavily ribbed for strength and stiffness and supports the front differential. The engine oil drain plug and oil temperature sensor are located on the underside of the oil pan, towards the rear. An oil baffle plate is incorporated in the oil pan to reduce oil foaming and slosh.

A gasket seals the joint between the oil pan and the cylinder block.

Oil Temperature Sensor

The engine oil temperature sensor, located in the oil pan, provides the ECM and the instrument cluster with the engine oil temperature status.

The sensor circuit consists of an internal voltage divider circuit, which incorporates a Negative Temperature Coefficient (NTC) thermistor. The output from the sensor is the change in voltage, as the thermistor allows more current to pass to ground relative to the temperature of the oil. For additional information, refer to: Electronic Engine Controls (303-14D Electronic Engine Controls - TDV8 3.6L Diesel, Description and Operation).

Drive is provided by 2 simplex bush timing chains, driven from the crankshaft to the inlet camshaft gears of each cylinder head.

Each exhaust camshaft is driven by a gearwheel arrangement from the intake camshaft.

Each timing chain is contained between 1 fixed and 1 hydraulically adjustable chain guide. The adjustable guides are of aluminium die casting construction with clip-fastened plastic slide linings. The fixed guides are moulded plastic. The adjustable guides are attached to the front of the cylinder block using pivot bolts, which allows it to pivot about its axis. A single tensioner provides hydraulic tension for the chains, 1 located in each cylinder head (for more information, see cylinder head section). The lateral movement in the adjustable guides causes the timing chain to tension and consequently, compensation for chain flutter and timing chain wear is automatically controlled.

The timing chains are oil splash lubricated, via the oil pump and chain tensioner. Oil spray is directed to the chain from several oil supply ports in the front of the cylinder block and cylinder head.

Cylinder Heads

The aluminium gravity die-cast cylinder heads are unique to each cylinder. Ten deep-seated bolts help reduce distortion and secure each cylinder head to the cylinder block. The cylinder head bolts are located beneath the camshafts, 5 under the inlet camshaft and 5 under the exhaust camshaft. Two hollow dowels align each cylinder head with the cylinder block.

Each cylinder head has 4 ports machined at each cylinder location, 2 exhaust ports and 2 inlet ports. One of the inlet ports is helical and functions as a swirl port, the other is arranged laterally as a tangential port and functions as a charge port.

Each cylinder head houses an automatic chain tensioner, which contains a hydraulically operated plunger that operates on the adjustable guides at the slack side of each of the timing chains. Pressurised oil for the adjuster is supplied through the back of the unit from an oil supply port in each cylinder head.

Camshafts

There is 1 exhaust camshaft and 1 intake camshaft per cylinder head. Each of the overhead camshafts are located in 5 bearings and maintained in position by 5 aluminium alloy bearing caps. Each of the bearing caps are fixed to the cylinder head by 2 bolts. Location letters and numbers are etched on the caps for each cylinder head, A to L for the LH head and 0 to 9 for the RH head. The camshafts are of a hollow steel tube construction, with pressed on steel lobes. The camshafts are driven from the crankshaft via simplex chains and a sprocket arrangement.

Each camshaft has 8 machined lobes for operating the inlet and exhaust valves through hydraulic lash adjusters and roller-type finger levers. The front of the RH cylinder head inlet camshaft provides a drive connection for the vacuum pump, via a drive gear. The front of the LH cylinder head inlet camshaft provides a drive connection for the high-pressure fuel pump, also via a drive gear.

The following table lists some unique features for each camshaft to avoid placement of camshafts in the wrong position:

Camshaft Identification Table

Inlet and Exhaust Valves

Two 27.5 mm inlet valves and 2 25.0 mm exhaust valves serve each cylinder. Each valve is of a ground, solid one-piece head construction and the stems are made from a Nimonic alloy material.

The valve springs are made from spring steel and are of the parallel single-coil type. The bottom end of each spring rests on the flange of a spring retainer, which has an integral valve stem seal. The top end of the spring is held in place by a spring retainer, which is held in position at the top end of the valve stem by split taper collets. The taper collets have grooves on the internal bore that locate to grooves ground into the upper stems of the valves.

The powder metal valve seats and guides are an interference fit in the cylinder head.

Valve Timing

Key

• BTDC = Before Top Dead Center
• ABDC = After Bottom Dead Center
• BBDC = Before Bottom Dead Center
• ATDC = After Top Dead Center

Hydraulic Lash Adjusters and Roller Finger Rockers

The valves are operated through roller-type finger rockers and hydraulic lash adjusters, actuated by the camshaft lobes. When the camshaft lobe presses down on the top of a finger rocker, roller mechanism, the respective valve is forced down, opening the effected inlet or exhaust port. The use of this type of actuation method helps reduce friction in the valve timing mechanism.

The body of the hydraulic lash adjuster contains a plunger and 2 chambers for oil feed and pressurised oil. The pressurised oil is supplied to the adjusters via the main oil galleries in the cylinder head and through a hole in the side of the adjuster body. The oil passes into a feed chamber in the adjuster and then through to a separate pressure chamber via a 1-way ball valve.

Oil flow from the pressure chamber is determined by the amount of clearance between the adjuster outer body and the centre plunger. Oil escapes up the side of the plunger every time the adjuster is operated, the downward pressure on the plunger forcing a corresponding amount of oil in the adjuster body to be displaced. When the downward pressure from the camshaft and finger rocker is removed (i.e. after the trailing flank of the camshaft lobe has passed), oil pressure forces the adjuster's plunger up again. This pressure is not sufficient to effect the valve operation, but eliminates the clearance between the finger rocker and top of the valve stem.

High-Pressure Fuel Pump

The high-pressure fuel pump supplies the common rail with fuel and is fixed to the front of the LH cylinder head. The pump is a 3-radial piston type and is driven by the intake camshaft of the LH cylinder head via the fuel pump drive gear. The Engine Management System (EMS) controls pump pressure (depending on engine speed and load) up to a maximum of 1700 bar.For additional information, refer to:

High-Pressure Fuel Rails

The fuel rails are manufactured from forged steel. They store the fuel at high pressure and prevent pressure fluctuations in the high-pressure system. A fuel rail pressure sensor is fitted into a threaded bore in the rear end of the RH rail. The sensor is connected to the ECM via the engine harness, which supplies a 5V power supply, ground and signal connections. The sensor is a diaphragm type sensor, which changes shape as the fuel pressure increases or decreases. The ECM compares this signal to values stored in its memory to calculate the actual fuel pressure present in the rail.For additional information, refer to:

Glow Plugs

The glow plugs are arranged centrally on the inlet side of the cylinder head, between the 2 inlet ports of each cylinder.

The purpose of the glow plugs is:

• Assist cold engine start
• Reduce exhaust emissions at low engine load/speed

The main part of the glow plug is a tubular heating element that protrudes into the combustion chamber of the engine. The heating element contains a spiral filament that is encased in magnesium oxide powder. At the tip of the tubular heating element is the heater coil. Behind the heater coil and connected in series is a control coil. The control coil regulates the heater coil to ensure it does not overheat and cause a possible failure. For additional information, refer to: Electronic Engine Controls (303-14D Electronic Engine Controls - TDV8 3.6L Diesel, Description and Operation).

Cylinder Head Gaskets

The cylinder head gasket is a multi-layer, laminated steel type and is available in 5 different thicknesses. The choice of gasket thickness is dependent on the maximum piston protrusion. Gasket thickness is identified by teeth cut into the rear end of the gasket.

To calculate the correct cylinder head gasket thickness, each piston must be measured at 2 points, with an average of the 2 measurements taken to determine the piston protrusion. The highest of the 4 measurements will determine the gasket required for that particular cylinder head.

CYLINDER HEAD GASKET SELECTION

Piston bump heights (protustion above block face) are as follows:

• Grade 1 gasket = 0.541 - 0.551mm (AD suffix part)
• Grade 2 gasket = 0.552 - 0.603mm (BD suffix part)
• Grade 3 gasket = 0.604 - 0.655mm (CD suffix part)
• Grade 4 gasket = 0.656 - 0.707mm (DD suffix part)
• Grade 5 gasket = 0.708 - 0.760mm (ED suffix part)

right-hand (RH) gasket

left-hand (LH) gasket

Camshaft Position (CMP) Sensor

The CMP sensor locates through a hole in a flange on the rear RH side of the LH cylinder head. The rear of the inlet camshaft incorporates a trigger wheel, which is used in conjunction with the sensor to measure engine position. For additional information, refer to: Electronic Engine Controls (303-14D Electronic Engine Controls - TDV8 3.6L Diesel, Description and Operation).

Exhaust Gas Recirculation (EGR) Valve Assembly

The combined EGR modulator and cooler assemblies are located inboard of each cylinder head, between the vee. The cooler side of the EGR valve assembly is connected to the vehicle cooling system via hoses. The exhaust side is connected directly into the exhaust manifolds on each side. The exhaust gas passes through the cooler and is expelled via the actuator and a metal pipe into the throttle housing. The EGR modulator is a Direct Current (DC) motor, which is operated via a reduction gear drive and is controlled by the ECM. The ECM uses the EGR modulator to control the amount of exhaust gas being recirculated in order to reduce exhaust emissions and combustion noise. The EGR is enabled when the engine is at normal operating temperature and under cruising conditions. For additional information, refer to: Engine Emission Control (303-08D Engine Emission Control - TDV8 3.6L Diesel, Description and Operation).

Oil Pressure Switch

The oil pressure switch is located in the front of the RH cylinder head. For more information, refer to the 'Lubrication System' section.

Inlet Manifold/Camshaft Cover

The inlet manifolds are integrated with the moulded camshaft covers and work in conjunction with the intake tracts within the cylinder heads to provide variable intake swirl through port deactivation. For additional information, refer to: Intake Air Distribution and Filtering (303-12D Intake Air Distribution and Filtering - TDV8 3.6L Diesel, Description and Operation).

The covers are manufactured from 2 layers of 2 mm sound-deadened steel that are bonded together by a visco-elastic damping material. This provides a fully formable, acoustically dead panel. The covers are rubber mounted and include additional foam absorbtion.

The LH cover incorporates the oil filler cap assembly.

The 8, side fed, piezo electrically controlled fuel injectors are mounted in the inlet manifold/camshaft cover, which locates them centrally in each cylinder head. An O-ring seals each injector to the manifold interface.

The start of fuel injection and the quantity of fuel injected is controlled directly by the ECM. For additional information, refer to: Electronic Engine Controls (303-14D Electronic Engine Controls - TDV8 3.6L Diesel, Description and Operation).

The lubrication system is a wet oil pan, pressure fed type. It lubricates the engine sliding surfaces, dissipates heat, absorbs fuel combustion residue and seals off the gap between the cylinder and piston.

Oil is drawn from the reservoir in the oil pan and pressurised by the crankshaft driven oil pump. The output from the oil pump is then filtered and distributed through internal oil passageways.

All moving parts are lubricated by pressure or splash oil. Pressurised oil is also provided for operation of the hydraulic adjusters and the timing gear chain tensioners.

The engine is lubricated by a force-fed oil circulation system with a full flow oil filter. The oil cooler forms a unit with the oil filter and fuel cooler, which is mounted centrally in the middle of the cylinder block between the 2 banks of cylinders. The engine oil is cooled using the engine cooling system. This eliminates the need for an additional engine oil cooler.

The fuel cooler, which forms part of the oil filter body, is also cooled by engine coolant. In addition there is a further fuel cooler in the return line to the fuel tank.

Oil returns to the oil pan under gravity. Large drain holes through the cylinder heads and cylinder block ensure the quick return of the oil, reducing the volume of oil required and enabling an accurate check of the contents soon after the engine stops.

System replenishment is through the oil filler cap on the LH inlet manifold/camshaft cover.

Turbocharger Oil Return

Due to the wide range of inclines the vehicle operates across, the geometry of the oil pan has been configured to guarantee oil pick-up across all operating angles. Land Rover have developed an oil-scavenge system to guarantee excellent oil flow through the turbochargers on severe side-slopes. Whilst the 60-degree cylinder bank angle of a V6 engine allows the turbochargers to be packaged relatively higher in the vehicle, to obtain the best configuration for the V8 engine, the turbochargers must be sited much lower. At extreme angles, there is a risk they may be below the oil level on the oil pan, restricting oil return flow. To overcome this, the engine uses a rotor pump located on the front of the vacuum pump, to help draw oil back from the turbochargers to guarantee good flow across the full range of operating angles.

Oil Pick-up

The moulded composite oil pick-up is immersed in the oil reservoir to provide a supply to the oil pump during all normal vehicle attitudes. A mesh screen in the inlet prevents debris from entering the oil system.

Oil Pump

The oil pump is a gear type pump and is bolted and dowelled to the front of the engine block. It is sealed by means of a rubber gasket, which is recessed into the oil pump housing. The pump inlet and outlet ports align with oil passages in the ladder frame.

The pumping element is an eccentric rotor, which is directly driven by flats on the crankshaft. An integral pressure relief valve regulates pump outlet pressure at 4.5 bar (65.25 Psi).

The front crankshaft oil seal is housed in the oil pump casing.

Oil Filter and Oil/Fuel Cooler Assembly

The oil filter is a replaceable cartridge installed on an adapter in the center of the 'vee'. An internal bypass facility permits full flow bypass if the filter is blocked. For additional information, refer to: Fuel Tank and Lines (310-01B Fuel Tank and Lines - V8 N/A 4.4L Petrol, Description and Operation).

The crankcase ventilation system ensures that all gasses emitted from the crankcase during engine running are separated from any oil particles. For additional information, refer to: Engine Emission Control (303-08D Engine Emission Control - TDV8 3.6L Diesel, Description and Operation).

Two fuel coolers are fitted to the vehicle. One is located in the 'vee' of the engine block, and has a coolant system connection to aid heat transfer. The second cooler is a body mounted cooler located in the fuel return line on the LH side of the engine compartment and is a fuel to air cooler.

The body mounted fuel cooler uses engine coolant, direct from the lower part of the radiator, to cool fuel returning to the tank from the High Pressure (HP) injection pump. For additional information, refer to: Fuel Tank and Lines (310-01B Fuel Tank and Lines - V8 N/A 4.4L Petrol, Description and Operation).

Oil Pressure Switch

The oil pressure switch, located in the front of the RH cylinder head, connects a ground input to the instrument cluster when oil pressure is present. The switch operates at a pressure of 0.15 to 0.41 bar (2.2 to 5.9 Psi).

Oil Level Gage

The oil level gage is located towards the front RH side of the oil pan. Two holes in the end of the gage indicate the minimum and maximum oil levels. There is a difference of approximately 1 liter (1 US quart) between the 2 levels.

The cast iron exhaust manifolds are unique for each cylinder bank. They are sealed to the cylinder head by means of a steel gasket. Sacrificial plastic sleeves are used to align the manifolds. These sleeves must be changed when refitting the manifolds. Spacers on the securing bolts allow the manifolds to expand and retract with changes of temperature while maintaining the clamping loads.

Each manifold has a connection for the EGR cooling inlet pipe.

The engine is fitted with 2 electronically controlled Variable Geometry Turbochargers (VGT), which are fixed to the exhaust manifold by a 3-hole flange with a steel gasket.