Discovery 2. Manual — part 409

ENGINE - TD5

DESCRIPTION AND OPERATION 12-1-33

Cylinder head flow

1 Cast-in groove between cylinder head and

camshaft carrier

2 Rocker shaft flow
3 Lash adjuster supply channels (10 off)
4 Non-return valve
5 Chain lubrication jet supply

6 Oil return from vacuum pump
7 Oil supply to timing chain tensioner adjuster
8 Oil supply to vacuum pump
9 Oil supply hole to camshaft sprocket and timing

chain

Oil passes to the cylinder head from the cylinder block via a non-return valve which is included to prevent oil draining
away from the lash adjusters when the engine is switched off.

Oil is passed to a cast-in groove between the top of the cylinder head and the camshaft carrier. The part of the channel
on the top left hand side of the cylinder head has ten cross-drillings which supply oil to the hydraulic lash adjusters
and finger followers. Lubrication oil fed to the lash adjusters passes up through the lash adjuster body and into the
socket of the finger followers. The oil exits the finger followers through a small hole to lubricate the surfaces between
the camshaft lobes and rollers.

An additional tapping is included at the front left hand side of the cylinder head to supply oil to the chain lubrication
jet, and a through hole near the front centre of the cylinder head allows a passage of oil through from the cast-in
groove to lubricate the timing chain and camshaft sprocket.

At the centre front of the cylinder head, the cast-in groove channels oil into the rockershaft via the front rockershaft
fixing. Oil flow through the rockershaft and clearance around the rockershaft fixings provides oil feed to the camshaft
bearings.

ENGINE - TD5

12-1-34 DESCRIPTION AND OPERATION

A tapping towards the right hand side of the cylinder head diverts oil supply from the cast-in groove down to a stub
pipe which attaches to a feed line to the vacuum pump. An hydraulic tensioner is located below the vacuum stub pipe
which receives oil through a small hole in the side of the tensioner body to force a plunger against a plastic faced
adjuster shoe for timing chain tensioning. Oil from the vacuum pump is returned to a port in the timing chain cover via
a short hose which connects to stub pipes at both ends using spring clips.