Volkswagen 1.4 16v Polo 2003 Owner's Manual

The 1.4-ltr. 16V 55kW Engine

with roller-type cam follower

Design and Function

196

Whether it’s a matter of better fuel economy, higher engine output or lower exhaust emissions - the demands on engines are constantly increasing. This presents our engineers with new tasks, with the result that the Volkswagen engine range is constantly growing.

Example: weight saving

During development, the weight of the new 1.4-ltr. 16V 55kW engine was reduced by about 10 kg by modifying its design.

This self-study programme explains the technical innovations in our engine range using the 1.4-ltr. 16V 55kW engine as an example.

Apart from minor differences in the engine mechanics, the 1.6-lr. 16V 88 kW engine for the Polo GTI will have these new features, too.

The Self-Study Programme

is not a Workshop Manual.

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These differences arise out of the various technical demands on the engines and are described in this Self-Study Programme.

New Importan

Precise instructions for testing, adjustment and

repair can be found in the appropriate Workshop

Manual.

At a glance

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Engine mechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Intake manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Valve gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Valve actuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

toothed belt drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Crankcase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Crankshaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Sealing flange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Oil pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Con rod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Exhaust system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Engine management . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Engine control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

System overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Static high-voltage distribution . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Engine speed sender G28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Hall sender G40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Functional diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Self-diagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Special-purpose tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Introduction

One of a “new generation”

The 1.4-ltr. 16V 55kW engine is the first of a new generation of engines featuring roller-type cam followers. It is fundamentally different from the 1.4-ltr. 16V 74kW engine with bucket tappets.

The main differences are:

- the die cast aluminium crankcase

- the cylinder head, where only the existing valve clearance and angle have been adopted.

New and advanced developments include:

the plastic intake manifold

the cylinder head and camshaft housing

valves are activated by roller-type cam followers

the crankcase is made of die cast aluminium

the duocentric oil pump

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The overall effects of these design modifications are:

- significant reduction in fuel consumption,

- performance on a par with predecessor models,

- weight savings and

- compliance with the more stringent exhaust gas limit values now in effect in Germany.

the exhaust manifold

the Magneti Marelli 4AV engine management system

Specifications

1.4-ltr. 16V 55kW engine

The 1.4-ltr. engine develops 128Nm of torque at 3200rpm. Maximum output is 55kW at 5000rpm.

1.6-ltr. 16V 88kW engine

By comparison, the 1.6-ltr. engine develops 148Nm of torque at 3400rpm and a maximum output of 88kW at 6200rpm.

Torque

[Nm]

Torque

[Nm]

Output

[kW]

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Engine speed [rpm]

Output

[kW]

1.6-ltr. engine1.4-ltr. engine

Engine code AHW

AKQ exhaust emission level D3

Displacement [cm

] 1390 1598

Bore/stroke [mm] 76.5 / 75.6 76.5 / 86.9

Compression ratio 10.5:1 10.6:1

Mixture preparation

Magneti Marelli 4AV Magneti Marelli 4AV

Engine management system

Fuel [RON] 95 / 91 98 / 95

Exhaust gas post-treatment Lambda control,

main catalytic converter for MVEG-A II for the AHW engine additional micro catalytic converter for exhaust emission level D3 for the AKQ engine

AJV exhasut emission level D3

Lambda control, primary and main catalytic converters for exhaust emission level D3

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Engine speed [rpm]

The knock control lets you run the 1.4- ltr. and 1.6-ltr. engines on RON 91 and RON 95 fuel respectively. This may result in a slight loss of power and torque.

Engine Mechanics

The plastic intake manifold

consists of three component parts which are welded together. The material is made of highgrade polyamide which is resistant to temperatures of up to 140°C for short periods of time.

The use of plastics has made it possible to keep the weight of the intake manifold down to three kilograms. As a result, the intake manifold is roughly 36% lighter than a comparable intake manifold made of aluminium. The plastic intake manifold also has a very smooth surface, and this improves the induced air flow.

induced air

The following components are mounted in the plastic intake manifold:

- the injectors,

- the fuel distributor,

- the throttle valve control unit and

- the intake manifold pressure sender and the intake air temperature sender.

The air filter housing is secured to the plastic intake manifold by two screws. The max. permissible tightening torque is

3.5Nm.

Middle section

Upper/lower parts of

intake manifold

An aluminium intake manifold is used for the 1.6-ltr. 16V 88kW engine. It has been adapted to the engine’s requirements.

Upper shell

The plastic intake manifold

of the 1.4-ltr. engine

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Valve gear

is accommodated in the cylinder head and camshaft housing.

The camshaft housing is by and large identical to the cylinder head cover which was previously used as standard.

What’s new is that the camshafts are now inserted into the housing. The bearing covers and camshaft housing limit the axial clearance of the camshafts. The camshafts run in three bearings.

The valve assembly comprising valves, rollertype cam followers and hydraulic support elements is located in the cylinder head.

Exhaust camshaft

Camshaft housing

Hydraulic support element

Intake camshaft

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Roller-type cam followerCylinder head

Bearing cover

Camshaft housing

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Cylinder head

Inserted camshaft

The gasket between the camshaft housing and the cylinder head is in the form of a fluid seal. Do not apply the sealant too thickly, since this may cause excess sealant to enter the oil drillings and damage the engine.

Engine Mechanics

Valve activation

With this engine generation, the valves are activated via a roller-type cam follower with a hydraulic support element.

Advantages:

- less friction

- fewer moving masses.

Conclusion:

Less engine power is required to drive the camshafts.

support element

Low-friction

roller bearing

Camshaft

Cam roll

Roller-type cam follower

ValveHydraulic

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Design

The roller-type cam follower comprises a sheetmetal moulding acting as a lever and a cam roll with a roller bearing. The cam follower is clipped onto the support element and seated on the valve.

The hydraulic support element has the same function as the hydraulic bucket tappet. It serves as a hydraulic valve lifter and support for the roller-type cam follower.

The lubrication system

Lubricant flows between the hydraulic support element and the roller-type cam follower as well as between the cams and the cam roll along an oil duct integrated in the support element. Oil is injected into the cam roll through a drilling in the roller-type cam follower.

Oil

Cam roll

Function

The support element serves as a pivot for the roller-type cam follower. The cam contacts the cam roll and presses the lever down. The lever in turn activates the valve.

A high valve lift is achieved with a relatively small cam due to the fact that the leverage between the cam roll and support element is smaller than between the valve and support element.

Lubricant duct

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It is not possible to inspect the hydraulic support elements.

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Engine Mechanics

The hydraulic support element

serves as a support for the roller-type cam follower and hydraulic valve lifter.

Design

The support element is connected to the oil circuit. It comprises the following elements:

- a piston,

- a cylinder and

- a piston spring.

A small ball, in combination with a pressure spring integrated in the lower oil chamber, makes up the one-way valve.

Hydraulic valve lifter

If valve backlash occurs, the piston spring forces the piston out of the cylinder until the cam roll makes contact with the cam. When the piston is pressed out of the cylinder, the oil pressure in the lower oil chamber drops. The one-way-valve opens and surplus oil flows into the oil chamber. The one-way-valve closes when the pressure between the lower and upper oil chambers has been equalised.

Oil inlet

Piston with drilling

Cylinder

Upper oil chamber

Lower oil chamber

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Piston spring

One-way valve

Valve clearance

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Valve lift

When the cam contacts the cam roll, the pressure inside the lower oil chamber rises because the oil here cannot be compressed. The piston cannot be forced any further into the cylinder. Thus, the support element acts as a rigid support for the roller-type cam follower. The inlet or exhaust valve opens.

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The toothed belt drive

The toothed belt drive is divided into a main drive and a connecting drive on account of the small overall width of the of the cylinder head.

Main drive

The coolant pump and the intake camshaft are driven by the crankshaft by means of a toothed belt integrated in the main drive. An automatic tension pulley and two deflection pulleys reduce toothed belt fluctuation.

Main drive

Deflection

pulley

Belt pulley

Coolant pump

Tension pulley

Main drive

Connecting drive

Tension pulley Connecting drive

Deflection pulley

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Belt-driven crankshaft gear

The connecting drive

is located outside the cylinder head.

The exhaust camshaft is driven by the intake camshaft by means of a second toothed belt integrated in the connecting drive.

Again, an automatic tension pulley reduces toothed belt fluctuation.

You can find exact instructions for adjustment the camshaft timing in the Workshop Manual.

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