300Tdi Discovery
Mpi
3
DESCRIPTION AND OPERATION
Lubrication
Oil is drawn from the pressed steel sump through a
strainer (1) and into the oil pump (2); excess pressure
being relieved by a pressure relief valve (3) integral
with the pump. The low oil pressure sensor (4)
registers the oil pressure in the main oil gallery on the
outflow side of the filter. Pressurised oil passes
through the full flow oil filter (5) to internal drillings in
the crankshaft where it is directed to each main
bearing and to the big end bearings via Nos. 1, 3 and
5 main bearings (6). An internal drilling in the cylinder
block directs oil, via a restrictor (7) to the cylinder
head where it passes through further internal drillings
to the hydraulic tappets and camshaft journals (8).
Gudgeon pin and small-end bush lubrication is by
splash from the big-end bearings.
Crankcase ventilation
With the exception of two hoses connected from the
inlet camshaft cover to the inlet manifold and throttle
housing all crankcase ventilation is via internal voids
in the cylinder head and block. The inlet camshaft
cover carries a wire gauze flame trap located over the
breather pipe connections.
