For 1990-2009 cars

### Cylinder Block

The cylinder block is constructed from aluminium alloy with cast-in-place iron cylinder bore liners. Each of the four copper-infiltrated sintered steel main bearing caps are attached to the cylinder block by six bolts. Along with two outer and two inner bolts, two side bolts are used in the deep skirt block for increased block stiffness. The crankshaft thrust bearing is mounted in the third main bearing cap.

To prevent aeration, oil return from the valve train and cylinder heads is channelled away from the reciprocating components through oil drain back passages incorporated into the cylinder heads and engine block. Pressure actuated piston oil cooling jets are mounted between opposing cylinders.

### Cylinder Head

The cylinder heads are semi-permanent mould cast aluminium with powdered metal valve seat inserts and valve guides. Each cylinder head contains 4 valves per cylinder. The valves are actuated by the rocker arms that pivot on stationary hydraulic lash adjusters, which are oil-fed to maintain valve/rocker lash.

The separate exhaust and intake camshafts are supported by four bearings machined into the cylinder head.

The front camshaft bearing cap is used as a thrust control surface for each camshaft.

A tube is pressed into each cylinder head in 3 places that shields each spark plug. An ignition coil assembly is mounted directly on each spark plug, through each spark plug tube.

### Crankshaft

The crankshaft is a forged steel design with four main bearings. The number three main bearing controls crankshaft thrust. A crankshaft position reluctor wheel is pressed onto the rear of the crankshaft, in front of the rear main journal. The crankshaft is internally balanced with an integral oil pump drive machined into the nose in front of the front main journal.

### Piston And Connecting Rod Assembly

The piston assembly is fitted with two low tension compression rings and one multi-piece oil control ring. The top compression ring is plasma sprayed, while the second compression ring is cast iron Napier.

The oil control ring incorporates a steel expander and two chrome plated steel rails.

The connecting rods are sinter forged steel and have full floating piston pins. The piston pins are a slip-fit type, into the bronze bushed connecting rods. Round wire retainers are used to retain the piston pin into the piston.

The cast aluminium pistons incorporate a polymer coated skirt to reduce friction.

### Camshaft Drive System

Three timing chains are fitted primary, right-hand secondary and left-hand secondary. The primary timing chain connects the crankshaft sprocket with the left-hand and right-hand intermediate drive shaft sprockets.

Each oil pressure fed intermediate sprocket drives the secondary timing chains, which subsequently drive the respective cylinder head camshaft position actuators.

Two stationary timing chain guides and movable timing chain shoes control secondary timing chain backlash. Each secondary timing chain shoe is under tension from an oil pressure hydraulically operated tensioner. To control backlash on the primary chain, two stationary timing chain guides and an oil pressure hydraulically actuated tensioner with built in shoe are fitted.

The tensioners minimize timing chain noise and provide accurate valve action by keeping slack out of the timing chains, while continuously adjusting for timing chain wear. The tensioners incorporate a plunger that adjusts outward with wear, minimizing backlash. The tensioners are equipped with oiling jets to spray oil onto the timing components during engine operation. Each tensioner is sealed to the head or block using a rubber coated steel gasket. The gasket traps an adequate oil reserve to ensure quiet start-up.

### Camshaft Position Actuator Control System

A variable camshaft timing system is fitted that allows camshaft phasing changes within a range of 25 camshaft degrees as engine operating conditions vary.

Camshaft phasing optimizes engine performance and fuel economy without compromising overall engine response and driveability. Variable camshaft timing also contributes to a reduction in exhaust emissions. The need for an exhaust gas recirculation (EGR) system is eliminated as exhaust and intake valve overlap is optimized.

A camshaft position actuator is fitted at the front of each camshaft that changes the camshaft lobe timing relative to the camshaft drive sprocket.

### Intake Manifold

A dual-stage variable intake manifold is achieved through the use of an intake manifold tuning control (IMTC) valve. The engine control module controlled IMTC alters the length and volume of the intake manifold plenum. Varying the intake manifold takes advantage of the natural pulse/pressure waves occurring in the manifold that are created by the process of air induction into the cylinders.

### Lubrication System

A structural diecast aluminium oil pan is fitted that incorporates an oil suction pipe, an oil deflector, an oil baffle and an oil level sensor. The oil suction pipe is bolted into the oil pan and seals to the bottom of the cylinder block with a gasket. The oil deflector is bolted to the upper portion of the oil pan and ensures oil supply is maintained under all conditions. The oil level sensor is mounted through the end of the oil pan.

A crankshaft driven gerotor oil pump is mounted to the front of the cylinder block. The pump, which incorporates an internal pressure-relief valve, draws oil from the oil suction tube through the lower passage in the cylinder block. Oil is then directed through an upper passage to the left-hand side of the cylinder block where the oil filter adapter is mounted.

The oil filter adapter incorporates a top-access, spin on style oil filter. The oil filter adapter housing incorporates a threaded oil pressure sender. Oil flows through a lower passage within the oil filter adapter and through the oil filter. Filtered oil travels back through the upper passage of the adapter and into the engine block.

Oil is then directed up and across the front of the cylinder block, through several drilled passages. These front passages feed oil to each cylinder head, the passage for the main bearings and piston oil jets, the right-hand and left-hand secondary idler sprockets and to the primary timing chain tensioner.

Each cylinder head passage directs oil into oiling circuits for the stationary hydraulic lash adjusters (SHLAs) and the camshaft bearing journals. Oil is also directed through two passages, each with a spring-loaded check-ball valve, to the chambers where the camshaft position actuator solenoid valves are mounted. An additional passage in the cylinder head also directs oil to the secondary timing chain tensioner.

The oil passage that supplies oil to the main bearings also supplies oil to pressure actuated piston cooling oil jets. Each oil jet is mounted between opposing cylinder bores and directs oil to the two bores to provide extra cooling and control piston temperatures.

From the front passages, oil is directed to the front of the block where the right-hand and left-hand intermediate drive shaft sprockets and the primary timing chain tensioner are mounted. Each camshaft timing chain tensioner relies on a gasket to maintain an oil reserve after the engine is turned off. All camshaft timing chain tensioners incorporate a small oil jet to supply an oil spray onto the camshaft timing chain components.

Oil returns to the oil pan, either through the camshaft timing chain area or through the drain back passages on the outboard walls of the cylinder heads and cylinder block.