Valve Clearance Adjustment

1. Insert a suitable bolt (M6 X 1.0, length 25-35 mm {0.99-1.3 in})  into the engine front cover upper blind plug and tighten it until it contacts the chain tensioner arm, and then rotate it back one turn. (Set the bolt slightly away from the chain tensioner arm so that it does not contact it.)
   Fig 4: Timing Chain Mounting Bolt With Torque Specifications

   Courtesy of MAZDA MOTORS CORP.
2. Using the cast hexagon on the exhaust camshaft, apply force counterclockwise to facilitate unlocking the chain tensioner ratchet.
3. Using a Hex bit socket (2.5 mm {0.098 in}) or T15 Tone bit socket, unlock the chain tensioner ratchet so that it can be lifted up.
   Fig 5: Rotating Cast Hexagon Counterclockwise

   Courtesy of MAZDA MOTORS CORP.
   Fig 6: Unlocking Chain Tensioner Ratchet

   Courtesy of MAZDA MOTORS CORP.
4. Using the cast hexagon on the exhaust camshaft, apply force in the direction of the engine rotation to increase tension on the chain.
   Fig 7: Cast Hexagon Applied Force Direction

   Courtesy of MAZDA MOTORS CORP.
   NOTE:

   • The chain tensioner rack is compressed using the chain tension generated by applying force to the exhaust camshaft in the direction of the engine rotation.
   NOTE:

   • The racket has not been unlocked if the bolt cannot be pressed in approx. 5 mm {0.2 in}.
     Fig 8: Compressing Chain Tensioner Rack Using Chain Tension

     Courtesy of MAZDA MOTORS CORP.
5. Screw in the bolt set in Step  1 approx. 5 mm {0.2 in} and secure the tensioner arm with the rack compressed.
   Fig 9: Bolt Dimensions

   Courtesy of MAZDA MOTORS CORP.
   • If the tensioner arm cannot be secured, return the bolt to its original position and repeat the procedure from Step ( 3).

Selected tappet = Removed tappet thickness + Measured valve clearance - Standard valve clearance

Fig 12: Camshaft Cap Bolts Loosening Sequence

Courtesy of MAZDA MOTORS CORP.

Valve clearance [Engine cold] 

IN: 0.22-0.28 mm {0.003-0.011 in} 

EX: 0.27-0.33 mm {0.011-0.012 in} 

Tightening procedure 

1. 5.0-9.0 N.m {51-91 kgf.cm, 45-79 in.lbf} 
2. 14-17 N.m {1.5-1.7 kgf.m, 11-12 ft.lbf 

Tightening torque 69-75 N.m {7.1-7.6 kgf.m, 51-55 ft.lbf} 

• If not aligned, loosen the camshaft sprocket bolt and repeat the procedure from Step  34.

Fig 18: Fixing Exhaust Camshaft Using Wrench

Courtesy of MAZDA MOTORS CORP.

Tightening torque 18-22 N.m {1.9-2.2 kgf.m, 14-16 ft.lbf} 

Tightening torque 8-11 N.m {82-117 kgf.cm, 71-101 in.lbf) 

Fig 20: Engine Front Cover Upper Blind Plug

Courtesy of MAZDA MOTORS CORP.

Tightening torque 10-14 N.m {102-142 kgf cm, 89-123 in.lbf} 

Fig 21: Engine Front Cover Lower Blind Plug

Courtesy of MAZDA MOTORS CORP.