Sump, Crankshaft and Oil Pump Components (Engine - Td4)

Pistons The four pistons have graphite-compound coated aluminium alloy skirts, which are gravity die cast and machined.

Each of the pistons has a swirl chamber machined in the head which partly contains the inlet air during the combustion process and helps provide turbulence for efficient air/fuel mixture to promote complete combustion. The recesses in the piston's crown also provide clearance for the valve heads.

The pistons are attached to the small-end of the connecting rods by fully floating gudgeon pins which are retained in the piston by circlips.

The pistons incorporate an oil cooling channel for piston and gudgeon pin cooling, oil being supplied under pressure from the piston lubrication jets.

Piston Rings Each piston is fitted with two compression rings and an oil control ring.

The top ring is barrel-edged and chrome plated, the 2nd compression ring is taper-faced and the oil control ring is chrome plated and features a bevelled ring with spring.

Piston Lubrication Jets The four lubrication jets (one for each cylinder) have a long hook-type nozzle and are fitted at the bottom right hand side of each cylinder by two socket screws.

The jets provide lubrication to the cylinder walls, and to the piston underskirt for cooling the pistons and lubricating the gudgeon pins and small-end bearings. The input port to each lubrication jet mates with a port provided in each mounting position, tapped at the underside of the cylinder block from a main gallery on the RH side of the block.

Oil Cooler and Oil Filter Housing The engine oil cooler assembly is located on the oil filter housing and is connected to the vehicle cooling system. Oil from the cylinder block passes through the oil filter housing and partial flow is directed through the oil cooler before it is returned to the cylinder block. The oil filter housing has an integral thermostatic valve which controls the amount of oil flowing through the oil cooler, dependent on the oil temperature.

The oil filter is a disposable paper type. The filter is removed by unscrewing the cap of the oil filter housing.

Oil Pressure Switch The oil pressure switch is located in a port in the oil filter housing. It detects when a low oil pressure condition occurs and initiates the illumination of a warning light in the instrument pack if the pressure drops below a given value.

High Pressure Fuel Pump The high pressure fuel pump supplying the common fuel rail is fixed to a flange on the front LH side of the cylinder block. The pump is a 3 radial piston type controlled by the DDE 4.0 engine management system and chain driven from the crankshaft at 0.75 x engine speed. ENGINE MANAGEMENT SYSTEM - EDC, DESCRIPTION AND OPERATION, Description.

Crankshaft Position (CKP) Sensor The crankshaft position sensor is mounted on the rear LH side of the cylinder block. The sensor is a Hall-effect type which acts on a profiled target on the flywheel. ENGINE MANAGEMENT SYSTEM - EDC, DESCRIPTION AND OPERATION, Description.

Sump, Crankshaft and Oil Pump Components

The sump, crankshaft and oil pump components are described below:

Sump The sump is a two piece aluminium die-cast construction. The sump assembly is sealed to the bottom of the engine block by means of a rubber and metal gasket and 19 fixing bolts. The four bolts at the gearbox end of the engine block are longer than the remaining 15 bolts. Liquid sealing compound is used to seal the sump to the engine block at defined points.