TD5 Defender
ENGINE
13
DESCRIPTION AND OPERATION
CYLINDER BLOCK
The cylinders and crankcase are contained in a single cast iron construction. The cylinders are direct bored and
plateau honed with lubrication oil supplied via lubrication jets for piston and gudgeon pin lubrication and cooling. It
is not possible to rebore the cylinder block if the cylinders become worn or damaged. Three metal core plugs are
fitted to the three centre cylinders on the right hand side of the cylinder block.
Lubrication oil is distributed throughout the block via the main oil gallery to critical moving parts through channels
bored in the block which divert oil to the main and big-end bearings via oil holes machined into the crankshaft. Oil
is also supplied from the cylinder block main gallery to the five lubrication jets which cool and lubricate the piston
and gudgeon pins. Plugs are used to seal both ends of the main oil gallery at front and rear of the engine block.
An oil cooler is fitted to the LH side of the engine block; ports in the oil cooler assembly mate with ports in the
cylinder block to facilitate coolant flow. Oil is diverted through the oil cooler, centrifuge filter and full-flow filter
before supplying the main oil gallery. A tapping in the oil filter housing provides a lubrication source for the
turbocharger bearings and an oil pressure switch is included in a tapping in the oil cooler housing which
determines whether sufficient oil pressure is available to provide engine lubrication and cooling.
Cylinder cooling is achieved by water circulating through chambers in the engine block casting. A threaded coolant
jacket plug is located at the front RH side of the cylinder block.
Cast brackets are bolted to both sides of the engine block for mounting the engine to the chassis on the LH and
RH hydramount studs.
The gearbox bolts directly to the engine block; a gearbox shim plate is located between the adjoining faces of the
gearbox and the flywheel side of the engine block and is fixed to the rear of the engine block by two bolts. Two
hollow metal dowels locate the rear of the cylinder block to the shim plate. The gearbox casing provides the
mounting for the starter motor.
A port is included at the rear left hand side of the cylinder block which connects to the turbocharger oil drain pipe
to return lubrication oil to the sump. A plug sealing the lubrication cross-drilling gallery is located at the front right
hand side of the cylinder block and plugs for the main lubrication gallery are located at the front and rear of the
cylinder block. Two plastic dowels are used to locate the cylinder head to the cylinder block and must be replaced
every time the cylinder head is removed from the cylinder block.