LR3/Disco 3
The aluminium alloy, thermal expansion, lightweight pistons, with semi-floating piston pins, are offset to the thrust side
and are carried on forged steel connecting rods. Pistons are supplied in four grades, 1, 2, 3 and 4. The pistons are
marked to ensure they are correctly oriented in the cylinder bore; the 'arrow' mark should be toward the front of the
engine.
The V6 petrol engine utilises forged steel H-sectioned connecting rods, with the piston pin being an interference fit in the
small end of the connecting rod. The big ends are horizontally split.
Selective bearing shells with two grades of thickness; standard and 0.25 mm undersize, control big end bearing diametric
clearance. The big-end upper and lower bearing shells are plain with locating tags.
Each piston is fitted with two compression rings and an oil control ring. The top compression ring has a nitrided surface, a
process that involves the diffusion of nitrogen into the surface layers of a low carbon steel. The formation of nitrides
provides an increased hardness. The 2nd compression ring is chrome-plated. The oil control rings have stainless steel
top and bottom rails and integral expander rings.
Jackshaft Assembly
The jackshaft assembly is located centrally in the upper part of the cylinder block. The assembly is used to supply drive to
each camshaft, via a chain. The LH camshaft is driven from the front of the jackshaft and the RH camshaft is driven from
the rear. The Jackshaft assembly is driven, via a chain, by the crankshaft gear at the front of the engine. The assembly is
held in position by a thrust plate.
Front Cover and Water Pump Assembly
5
-
Piston pin
6
-
Connecting rod
7
-
Oil squirt hole
8
-
Connecting rod bearing, upper
9
-
Connecting rod bearing, lower
10
-
Connecting rod cap
11
-
Nut
12
-
Bolt
Item Part Number Description
1
-
Jackshaft
2
-
Thrust plate
