Range Rover P38
12
ENGINE
NEW RANGE ROVER
6
DESCRIPTION AND OPERATION
DESCRIPTION - up to 99MY
For description and operation of V8 engine before
99MY, refer to 4.0/4.6 V8 Engine Overhaul Manual.
DESCRIPTION - from 99MY
General
The V8 petrol engine is an eight cylinder, water cooled
unit having two banks of four cylinders positioned at
90 degrees to each other. The engine comprises five
main castings - two cylinder heads, cylinder block,
front cover and the oil sump, all of which are
manufactured from aluminium alloy. The engine is
available in 4.0 litre and 4.6 litre versions and each
type can be supplied as high compression or low
compression variants, dependent on market
requirements.
Cylinder heads
The cylinder heads are fitted with replaceable valve
guides and valve seat inserts with the combustion
chambers formed in the head. Each cylinder head is
sealed to the cylinder block with a multi-layer gasket.
The exhaust manifolds are bolted to the outside of
each cylinder head whilst the inlet manifolds are
located in the centre of the ’Vee’ and are bolted to the
inside face of each head. Inlet and exhaust manifolds
are sealed to the cylinder heads by means of gaskets.
Each cylinder has a single inlet and exhaust valve.
The exhaust valves are of the ’carbon break’ type, a
recess on the valve stem prevents a build-up of
carbon in the valve guide by dislodging particles of
carbon as the valve stem moves up and down the
guide. Inlet and exhaust valve stem oil seals are fitted
at the top of each valve guide. Valve operation is by
means of rocker arms, push rods and hydraulic
tappets. Each of the rocker arms is located on a
rocker shaft which is supported by means of pedestals
bolted to the cylinder heads. A spring, positioned on
either side of each rocker arm, maintains the correct
relative position of the arm to its valve stem. The
rocker arms are operated directly by the push rods
which pass through drillings in the cylinder heads and
cylinder block. The bottom end of each push rod
locates in a hydraulic tappet operated by the single,
chain driven camshaft.
The rocker covers are bolted to the cylinder heads
and are sealed to the heads by a rubber gasket. Stub
pipes for crankcase ventilation hose connections are
fitted to each rocker cover, the pipe in the right hand
rocker cover incorporates an oil separator. The engine
oil filler cap is situated in the right hand cover.
Cylinder block and camshaft
The cylinder block is fitted with cast iron cylinder liners
which are shrink-fitted and locate on stops in the
block. The camshaft is positioned in the centre of the
cylinder block and runs in one-piece bearing shells
which are line bored after fitting. Camshaft end-float is
controlled by a thrust plate bolted to the front of the
cylinder block. A timing gear, chain driven by the
crankshaft timing gear is bolted to the front of the
camshaft.
Crankshaft and main bearings
The crankshaft is carried in five main bearings. The
upper main bearing shell locations are an integral part
of the cylinder block casting. The lower main bearing
caps are bolted to the cylinder block on either side of
the upper bearing shell locations with an additional
bolt being inserted into each cap from either side of
the cylinder block. The rear main bearing cap carries
the crankshaft rear oil seal and is sealed to the
cylinder block by means of cruciform shaped seals in
each side of the cap. Number four main bearing cap
carries the stud fixing for the oil pick-up pipe. Lower
main bearing shells are plain whilst the upper shells
have an oil feed hole and are grooved. Crankshaft
end-float is controlled by the thrust faces of the upper
centre shell. The crankshaft timing gear is located on
the front of the crankshaft by means of a Woodruff key
which is also used to drive the gear type oil pump.
The drive plate incorporates the crankshaft position
sensor reluctor ring, and the assembly is dowel
located and bolted to the crankshaft.