Mazda Training manual - part 24

 

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Mazda Training manual - part 24

 

 

Powertrain Engines 

Valve Actuation 

• 

The camshafts actuate the valves via roller cam followers. 

• 

The valve clearance has to be measured between the roller cam follower and the cam 
lobe, and is adjusted through the adjusting screw of the roller cam follower (refer to the 
workshop manual for details). 

 

NOTE:  In order to prevent damage to the claw of the roller cam follower when loosening the 

locknut of the adjusting screw, the cam lobe must push down the roller cam follower 
firmly (refer to the illustration below).  

 
• 

The valve clearance has to be checked (and if necessary adjusted) for the first time after 
20,000 km or 12 months (whichever occurs first). After that it has to be checked (and if 
necessary adjusted) every 120,000 km or 6 years (whichever occurs first). 

 

L1001.4_01077 

 

Cam lobe 

Roller cam follower 

2 Adjusting 

screw 

5 Claw 

3 Locknut 

6 Roller 

 

Curriculum Training 

01-83 

Engines Powertrain 

Valve Train 

• 

The camshafts are driven via a timing belt by the fuel high-pressure pump pulley/gear, 
which in turn is driven via helical gears by the crankshaft.  

• 

The timing belt and the timing belt tensioner have to be replaced every 120,000 km. 

 

L1001.4_01078 

 

Camshaft pulley 

Crankshaft gear 

Intake camshaft 

Idler gear no.1 

3 Exhaust 

camshaft 

10 Idler gear no.2 

Roller cam follower 

11 

Fuel high-pressure pump pulley/gear 

5 Balancer 

shaft 

12 Tensioner 

pulley 

Balancer shaft gear 

13 

Timing belt 

Idler gear no.3 

14 

Idler pulley 

 

01-84 Curriculum 

Training 

Powertrain Engines 

• 

The crankshaft gear and the fuel high-pressure pump gear are equipped with friction 
gears. The spring-loaded friction gears eliminate the backlash between the meshing 
gears, reducing gear noise. 

 

NOTE:  Before removing the fuel high-pressure pump gear, the friction gear must be fixed to 

the fuel high-pressure pump gear using a detent bolt (M6 x 1.0, length approx. 16 
mm) to prevent it from rotating due to the spring force. 

 

L1001.4_01153 

 

Hole for detent bolt 

Friction gear 

Fuel high-pressure pump gear 

Helical gear 

3 Spring 

  

 

Curriculum Training 

01-85 

Engines Powertrain 

Timing Belt Tensioner 

• 

The WL-C engine features a modified automatic timing belt tensioner with integrated 
tensioner pulley. However, the operating principle is the same as on the RF-T engine.  

 

 

L1001.4_01080 

 

Tensioner rod 

Plunger spring 

2 Seal 

5 Pressure 

chamber 

3 Plunger 

6 Check 

valve 

 
• 

For releasing the belt tension the timing belt tensioner has to be turned counterclockwise 
with an Allen key, and secured by inserting a locking pin with 6 mm diameter (refer to the 
workshop manual for details).. 

 

NOTE:  When removing the timing belt tensioner, the tensioner pulley must not be separated 

from the tensioner housing. 

 

NOTE:  In case air has entered the pressure chamber of the timing belt tensioner, it must be 

bled using a certain procedure (refer to the workshop manual for details). 

 

L1001.4_01079 

 

Apply force (max. 39 Nm) 

Hole for locking pin 

2 Mounting 

bolts 

  

 

01-86 Curriculum 

Training 

 

 

 

 

 

 

 

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