Part 3

Engine

Fuel Rail and Injectors









The fuel rail maintains a fuel pressure of 3.8 bar (55 psi) above manifold depression under normal operating conditions, though this is programmed to rise to 4.2 bar (61 psi) in response to either:
- Cold start conditions, to improve fuel vaporization
- Cold fuel conditions, as the colder the fuel the higher viscosity
The fuel rail is attached to the intake side of the cylinder head with 3 bolts. Six fuel injectors are installed in the cylinder head and connected to the fuel rail. 'O' ring seals are used to seal the injectors in both the fuel rail and cylinder head. A connection for the fuel pressure pipe is located between injectors 1 and 2.
There is a fuel rail pressure and temperature sensor located at the end of the fuel rail, next to injector number 6. The pressure sensor continuously monitors the fuel pressure in the fuel rail, this value is used by the ECM to calculate the injector pulse-width required to deliver the correct mass of fuel per injection. The temperature sensor measures the temperature of the fuel in the fuel rail. This input is then used to deliver the correct quantity of fuel to the engine. For additional information, refer to Electronic Engine Controls - 3.2L Electronic Engine Controls

Vacuum Pump









The intake camshaft is equipped with the VCT unit. The intake camshaft also drives the vacuum pump.

NOTE:
When installing the vacuum pump make sure the slot in the VCT unit and the vacuum pump coupling are in the vertical position to aid installation. The vertical position is marked on the vacuum pump housing by 2 raised lines.


Intake Manifold









The intake manifold attaches to the cylinder head with 6 bolts and the oil pan with 2 bolts.
The manifold is capable of varying both intake tract length and plenum volume by means of 2 separate valves.
At low engine speeds, long intake tracts are utilized to provide optimum engine torque. Shorter tracts are used at medium speeds, again, to optimize engine torque for the existing engine speed range.
At higher engine speeds the benefits of optimizing the tract lengths are outweighed by the necessity of maintaining an appropriate supply of air to meet the engines requirements. Therefore, the plenum valve is opened to create a single, large plenum volume to provide the maximum quantity of air to charge the engines cylinders. For additional information, refer to Intake Air Distribution and Filtering - 3.2L Intake Air Distribution and Filtering

Exhaust Manifold









The exhaust manifold comprises 2 separate manifold assemblies. One manifold is used for cylinders 1 to 3 and the second manifold is used for cylinders 4 to 6. The manifolds are sealed to the cylinder head with a gasket and secured with 14 bolts.
Each manifold comprises 3 fabricated branches, which merge into an integral catalytic converter. A threaded boss is positioned where the 3 branches merge and provides for the fitment of a pre-catalyst Heated Oxygen Sensor (HO2S). The catalytic converter outlets have offset flanges which mate with corresponding flanges on the front section exhaust system.
A bracket on each outlet flange allows for the attachment of an exhaust manifold heat shield.

CRANKSHAFT, BEDPLATE AND OIL PAN COMPONENTS
The crankshaft and oil pan components are:
- Crankshaft and main bearings
- Crankshaft vibration damper and cooling valve
- Bedplate
- Oil filter and cooler assembly
- Oil pump assembly
- Oil pick-up
- Oil pan
- Oil level gage
- Starter motor

Crankshaft and Main Bearings













The crankshaft is made of forged steel and has induction hardened bearing surfaces. There are 2 types of aluminium main bearing:
- With complete oil ducts for upper main bearings 2, 3, 5 and 6
- With short oil ducts for all lower and 1, 4 and 7 upper main bearings
Due to missing counter-weights for cylinders 1 and 6 and selected counter-balancing of the entire crankshaft, main bearings 1, 4 and 7 are exposed to greater loads than the others. To reduce the load on the bearings, bearing shells with short oil ducts are used. In addition, these main bearings have their own oil circuit where the oil is not distributed on to the connecting rod bearings. The 6th main bearing also works as a thrust bearing.
A gear wheel is crimped to the rear edge of the crankshaft. The gear wheel drives the oil pump and the Rear End Ancillary Drive (READ) timing gear.
The crankshaft has a viscous vibration damper located directly in front of the connecting rod pin for cylinder 1, i.e. located in the actual cylinder block.

Crankshaft Vibration Damper and Cooling Valve









One of the remedies for obtaining a compact engine unit is to place the crankshaft vibration damper inside the engine block. The damper has been positioned at the front of the crankshaft between the end and the connecting rod pin for the crankshaft for cylinder 1.










The damper consists of a solid steel ring, placed in an enclosed housing filled with silicon fluid. The ring is radially journaled through a plastic bearing. There are buttons on the front and rear side surfaces, 4 on each side. These buttons are axially journaled.
The task of the damper is to even out fast unwanted increases and reductions in speed (i.e. crankshaft oscillations) and to give the crankshaft a smoother operation.
When the rotation speed of the crankshaft increases or reduces quickly, the change in speed of the steel ring is delayed due to the high viscosity of the silicon fluid. The function of the damper is based on the braking effect of the silicon fluid and the steel ring's own inertia. When the ring moves in the silicon fluid in the damper housing, a large amount of heat is generated that must be routed away.









Because the damper is located in an environment where the normal operating temperature can reach approximately 140°C (284°F), coupled with the fact that the damper also generates its own heat, it is necessary for it to be oil cooled. A separate oil circuit routes oil from the engine's oil cooler to a valve in the engine block, which opens at approximately 2 bar. The oil then flows to 3 jets, located on the crankshaft vibration damper cooling pipe, which then directs the oil to the lower section of the damper.
The oil flows through the jets at approximately 12 liters per minute.
At high temperatures, oil cooling reduces the damper temperature by approximately 7°C (45°F).

Bedplate





The bedplate is of an aluminium alloy structure bolted to the bottom of the cylinder block to further improve rigidity and to retain the crankshaft. The 7 cast iron crankshaft bearing caps are cast in the boreholes.
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.

Oil Filter and Cooler Assembly









The oil filter and cooler assembly is located at the front of the LH side of the cylinder block. The oil filter housing contains a separate single oil filter element. The oil filter supplies clean oil to the oil cooler, which is connected to the coolant system, and is further distributed to the various engine systems (For more information refer to the lubrication section).

Oil Pump Assembly









The oil pump is attached to bottom of the bedplate via a pivot pin and a bolt. The pump is an external gear wheel pump with integrated pressure control valve (for more information refer to the lubrication section).

Oil Pick-up









The fabricated steel 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 intake prevents debris from entering the oil system.

Oil Pan









The aluminium alloy structural oil pan is bolted to the bedplate.

NOTE:
The oil pan should always be fitted proud of the bedplate by 0.05mm (+0mm -0.05mm).
A combined oil level/temperature sensor is attached to the underside of the oil pan via 3 bolts. The tip of the sensor locates through an aperture and is sealed with an O-ring.









The engine oil drain plug is located on the exhaust side of the engine, towards the bottom of the oil pan.

Oil Level Gage









The oil level gauge locates along the intake side of the engine and is supported in a tube installed in the oil pan. A bolt securely attaches the tube to the engine oil cooler via a bracket. Two holes in the end of the gauge indicate the minimum and maximum oil levels. The difference between the dipstick markings, minimum and maximum, corresponds to 0.8 liters.

Starter Motor





The starter motor is located in a recess at the rear of the exhaust side of the oil pan. The motor, rated at 1.4 kW, uses permanent magnets instead of field windings to provide a low-weight starter motor; with the use of planetary gears to deliver a good torque to weight ratio For additional information, refer to Starting System - 3.2L Description and Operation.

CAMSHAFT TIMING COMPONENTS









The timing chain for the camshafts is located in a housing at the rear of the engine.

















The timing chain is driven by the camshaft chain gear via the crankshaft. The chain drives both the intake and exhaust camshafts. The chain is continually tensioned by a hydraulic chain tensioner and is lubricated by oil via a separate nozzle. The tensioner has an inhibitor that prevents the chain from slackening in the event of reversed loading.
The intake camshaft is equipped with a VCT unit and also drives the vacuum pump.
The return oil from the camshafts housing is routed to the gear housing and lubricates the timing gear's bearings and gear wheel.

LUBRICATION SYSTEM





The lubrication system components and functions are:
- Oil pick-up
- Oil pump
- Oil filter and cooler assembly
- Intake valve (piston cooling)
- Cylinder head oil supply
- Gear housing

Oil Pick-up
The oil pick-up contains a strainer, which separates large contaminants and prevents them from reaching the oil pump.

Oil Pump
The oil pump is an external gear wheel pump with integrated pressure control valve. The valve opens at approximately 4.5 bar and controls the system pressure.
The pump is driven by the crankshaft and is 1.3 times faster than the crankshaft.
To ensure that the air is released from the oil system, a valve is located in the oil pump on the pressure side. During the build-up of pressure, air is routed out into the crankcase. This continues until the valve closes at approximately 0.2 bar.

Oil Filter and Cooler Assembly
The majority of oil is routed to the oil filter, which is a separate single filter element located in the housing. The over-flow valve for the blocked filter is in the cover. The valve opens at approximately 2 bar.
There is a valve at the bottom of the housing. The task of the valve is to drain the housing of oil when the oil filter is removed. When the oil filter is installed, the valve is closed. A spring loaded ring at the bottom of the filter housing is affected by the actual filter. The ring is, in turn, mechanically connected to the valve.
When the filter is removed, the spring lifts the ring, which, in turn, opens the valve whereupon the oil drains to the oil pan.









The oil passes a non-return valve before it reaches the oil cooler/filter housing. The non-return valve ensures that the oil filter housing is not drained of oil when the engine is switched off. The valve opens at approximately 0.2 bar.
The oil first passes the oil cooler, a plate oil cooler. The chamber for oil and coolant is split alternately between the plates. There are 20 plates used in total. The first 16 plates are used for oil, which is routed through the engine's normal lubrication circuit, i.e. the oil is routed to the oil filter.
The 4 last plates are used to provide a proportion of the oil with extra cooling before it is routed onwards to cool the vibration damper. The circuit is calibrated to achieve correct flow.
There is a by-pass valve parallel to the oil cooler. The valve ensures an oil flow to the oil filter even if the oil cooler is blocked. The valve opens at approximately 2 bar.

Intake Valve (Piston Cooling)
The oil is also routed to the duct for oil cooling, which is parallel to the ducts for main bearings and connecting rod bearings.
The oil first passes a valve that opens/closes at approximately 2.0 bar. Thereafter, the oil is routed to the jets for piston cooling:
- If the valve has too high an opening pressure, this means that the oil flow to the pistons reduces, which can cause engine damage
- If the valve has too low an opening pressure, this produces an increased flow to piston cooling. It can, in certain situations (before the relief valve is opened) result in the engine's oil pressure being too low causing engine damage
The jets direct the oil towards the underneath of the pistons. Each cylinder has its own jet.

Cylinder Head Oil Supply
Oil is routed from the cylinder block through a front and rear duct to the cylinder head. The duct at the front edge supplies 2 circuits in the cylinder head with oil:

1. Circuit for the hydraulic tappets, vacuum pump and cam chain lubrication
A longitudinal duct on the intake side supplies the following components with oil:
- The hydraulic tappets
- The vacuum pump
- The nozzle for cam chain lubrication

2. Circuit for the intake camshaft's front bearing, the CPS valves and the tappets with CPS function
A duct supplies the intake camshaft's front bearing and both the CPS valves.
The front CPS valve controls the oil flow to the tappets for cylinders 1, 2 and 4 and the rear CPS valve controls the oil flow to the tappets for cylinders 3, 5 and 6.
When the CPS valve solenoids are activated, the valves open (i.e. shift from low to high valve lifting height) and the tappets are supplied with oil under pressure.
The longitudinal duct that supplies the rear CPS valve is equipped with a bleed hole. This is to ensure that no air reaches the CPS valves or the tappets.





The duct is also equipped with 2 calibrated passages to each tappet circuit (i.e. the circuits after the CPS valves). A continuous flow through the circuit ensures the necessary stable pressure differences required for a stable transfer between the small and large tappet (or vice versa).

NOTE:
In the event of a small lifting height, the tappet circuit, in principle, has no pressure when the CPS valves are open, which produces a return flow to the oil pan.
A filter is located in each passage.
The duct at the rear edge supplies the following components/functions with oil:
- The camshaft chain's hydraulic tensioner
- The VCT valve and the VCT unit for the intake camshaft
- The camshaft bearings for the intake camshaft (6, i.e. all except the front)
- The camshaft bearings for the exhaust camshaft (all 7)

Gear Housing
The drained oil from the camshaft chain housing is supplied to bearings and meshings, i.e. the oil is not pressurized. The oil is routed through the bottom of the gear housing via the rear bearing, onwards into the housing where the meshings and front bearing are spray lubricated.
The internal needle bearings between the shafts are also supplied by the oil on its way out from the camshaft chain housing. The oil reaches the bearings through the opening between the shafts.
Even the intermediate shaft bearings are lubricated by the oil that is sprayed around the housing.