Jaguar XJ (X350). Manual — part 370

tensioner blades, the secondary chain tensioners act directly on the chains.

A woodruff key locates the drive sprocket on the crankshaft and these are retained in position by the

crankshaft damper pulley.

Item

Part Number

Description

1

—

Variable valve timing unit

2

—

Secondary chain

3

—

Secondary chain tensioner

The variable valve timing (VVT) oil control unit and the exhaust camshaft sprockets are non-

interference. They are clamped in place on the camshafts by the retaining bolt and clamping

plate/washer.

Timing Cover

Item

Part Number

Description

1

—

Crankshaft front oil seal

2

—

Poly-acrylic seal

The aluminium-alloy timing cover accommodates the crankshaft front oil seal. Poly-acrylic seal in-

groove gaskets seal the joint between the timing cover and the front face of the engine.

Cylinder Heads and Valve Gear

Item

Part Number

Description

1

—

Cylinder head bolt

2

—

Coolant outlet

3

—

Valve lifter

4

—

Adjustment shim

5

—

Camshaft

Cylinder heads are unique to each cylinder bank and are secured, using deep seated bolts, to the

cylinder block. Two hollow dowels align each cylinder head with the cylinder block.

Each cylinder head gasket consists of a silicon beaded composite gasket with metal eyelets for the

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cylinder bores.

Each cylinder head incorporates dual overhead camshafts operating four valves per cylinder via solid

aluminium-alloy valve lifters. A steel shim in the top of each lifter allows adjustment of valve

clearances.

Collets, valve collars and spring seats locate the valve springs on the intake and exhaust valves. Valve

stem seals are integrated into the spring seats.

Four 14mm spark plugs are located in a recess on the center-line of each cylinder head. <<303-07B>>

Camshafts

The chilled cast iron camshafts are each retained by five aluminium alloy caps - location numbers 0 to

4 for the intake camshaft and 5 to 9 for the exhaust camshaft from the front.

A machined flat near the front of each camshaft enables the camshafts to be locked during the valve

timing procedure.

Camshaft Sensor

The camshaft sensors are fitted to the rear of each cylinder head and are triggered by four toothed

sensing rings fitted to the rear of the intake camshaft. The camshaft sensors are variable reluctance

sensors that provides an input to the ECM of intake camshaft position.

Camshaft Covers

The valve covers are made from thermoplastic plastic; the right-hand bank cover incorporates an

outlet for the part load engine breather.

The left-hand bank cover incorporates the engine oil filler cap and an outlet for the full load engine

breather. Identical oil separators are incorporated inside the top of each cover. Each oil separator

comprises a wire gauze packing in an open ended enclosure below the breather outlet.

Bedplate

Item

Part Number

Description

1

—

Bedplate

2

—

Sealant track

This is a structural casting bolted to the bottom of the cylinder block to retain the crankshaft and to

further improve overall rigidity.

Main bearing clearance changes due to expansion are minimized by means of iron inserts cast into

the bedplate main bearing supports.

Two hollow dowels align the bedplate with the cylinder block and the joint is sealed by a continuous

bead of sealant.

Engine Mountings

The engine is mounted at two points. At each side of the engine, there is a mounting bracket with a

hydraulic mounting to the subframe.

Engine Lubrication

Oil is drawn from the reservoir in the oil pan and pressurized by the oil pump. The output from the oil

pump is then filtered and distributed through the internal oil passages.

Where an oil cooler is fitted, the oil is cooled before entering the filter.

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