Mazda Training manual - part 7

Powertrain Engines 

Valve Train 

• 

The camshafts are driven by a maintenance-free pinned link timing chain. 

 

L1001.4_01010 

 

1 

Exhaust camshaft sprocket 

7 

L3 engine 

2 

Timing chain 

8 

Chain guide 

3 

Intake camshaft sprocket 

9 

Crankshaft sprocket 

4 

L8, LF engine 

10 

Chain tensioner 

5 

Pitch size 

11 

Chain tensioner arm 

6 Pin 

  

 
 

Curriculum Training 

01-15 

Engines Powertrain 

Timing Chain Tensioner 

• 

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

• 

The timing chain tensioner operates using engine oil pressure. The ratchet and the rack 
hold the piston in place when the engine is started. 

 

L1001.4_01011 

 

1 

Hole for a ratchet lock 

5 

Plunger 

2 

Ratchet spring 

6 

Plunger spring 

3 Ratchet 

7 Check 

valve 

4 

Rack 

8 

Oil supply hole 

 

01-16 Curriculum 

Training 

Powertrain Engines 

• 

The timing chain tension can be released as following (refer to the workshop manual for 
details): 

1.  Using a suitable screwdriver or equivalent tool, unlock the chain tensioner ratchet. 

2.  Turn the exhaust camshaft clockwise using a suitable wrench on the cast hexagon, 

and loosen the timing chain. 

3.  Placing a bolt (M6 x 1.0) in the engine front cover upper blind plug hole, secure the 

chain tensioner arm in the position where the tension is released. 

 

L1001.4_01012 

 

1 

Direction of rotation 

3 

Detent bolt 

2 

Unlocking the chain tensioner ratchet 

 

 

 
 

Curriculum Training 

01-17 

Engines Powertrain 

Variable Valve Timing System 

• 

The variable valve timing system continuously varies the valve timing of the intake 
valves, controlling the cylinder charge.  

• 

The camshaft actuator is attached to the camshaft sprocket and varies the position of the 
intake camshaft in relation to the sprocket. The intake camshaft position is controlled by 
the oil control valve using engine oil pressure.  

 

NOTE:  The camshaft actuator cannot be repaired due to its precise interior construction, i.e. 

it must be replaced as a complete unit. 

 

L1001.4_01140 

 

1 

Oil control valve 

3 

Camshaft actuator 

2 Intake 

camshaft 

  

 

01-18 Curriculum 

Training