Mazda Training manual — part 20

Powertrain Engines

Valve Train

•

The camshaft is driven by a timing belt, which has to be replaced every 120,000 km.

L1001.4_01066

1

Camshaft pulley

7

Crankshaft pulley

2

Camshaft

8

Timing belt tensioner

3

Rocker arm

9

Tensioner pulley

4

Rocker bridge

10

Water pump pulley

5

Fuel high-pressure pump pulley

11

Timing belt

6 Idler

pulley

Curriculum Training

01-67

Engines Powertrain

Timing Belt Tensioner

•

An automatic timing belt tensioner is fitted to ensure optimum belt tension over the
service life of the engine.

•

The timing chain tensioner operates using a hydraulic mechanism, which also
compensates the increased belt tension due to heat expansion of the engine
components.

L1001.4_01120

1 Timing

belt

6 Plunger

2 Tensioner

pulley

7 Spring

3

Plunger spring

8

Tensioner rod

4

Pressure chamber

9

Tensioner arm

5 Check

valve

01-68 Curriculum

Training

Powertrain Engines

•

When replacing the timing belt, the timing belt tensioner has to be checked as following
(refer to the workshop manual for details):

–

Measure the tensioner rod projection length.

–

Inspect the tensioner for oil leakage.

–

Verify the thrust/resistance of the tensioner.

NOTE: If the tensioner rod projection length and/or tensioner thrust/resistance exceeds the

specification and/or there is an oil leakage, replace the timing belt tensioner.

•

Before installing the timing belt tensioner, the tensioner rod has to be pushed down and
secured by inserting a locking pin with 1.5 mm diameter (refer to the workshop manual
for details).

NOTE: Placing the timing belt tensioner horizontally while pushing the tensioner rod can

cause oil leakage and damage the automatic tensioner.

NOTE: To prevent damage to the timing belt tensioner, the tensioner rod has to be pushed

slowly with a force not greater than the specified 235 N. The tensioner rod must not
touch the bottom.

L1001.4_01067

1

Tensioner rod

3

Locking pin

2

Tensioner rod projection length

Curriculum Training

01-69

Engines Powertrain

Valve Timing

•

For verifying or adjusting the valve timing the timing marks have to be aligned as shown
below (refer to the workshop manual for details).

•

Before installing the timing belt the camshaft pulley must be fixed to the cylinder head
using a bolt (M8 x 1.25). In addition, the fuel high-pressure pump pulley has to be locked
against rotation with the aid of the FIP (Fuel Injection Pump) repair kit (part no. RFY1-13-
SMO).

NOTE: In order to prevent damage to the camshaft pulley, the detent bolts do not have to be

fully tightened.

L1001.4_01068

1

Timing mark (camshaft pulley)

4

Timing mark (crankshaft pulley)

2

Timing mark (fuel high-pressure pump
pulley)

5

Hole for detent bolt

3 FIP

repair

kit

01-70 Curriculum

Training