Mazda Engine SKYACTIV-G 2.5. Manual - part 13

MECHANICAL 

01-10–36

Standard bearing oil clearance at the large end of the connecting rod

0.026—0.052 mm {0.0011—0.0020 in}

Maximum bearing oil clearance at the large end of the connecting rod

0.10 mm {0.0039 in}

Connecting rod bearing size

STD: 1.502—1.519 mm {0.05914—0.05980 in}

OS 0.25: 1.628—1.631 mm {0.06410—0.06421 in}

OS 0.50: 1.753—1.756 mm {0.06902—0.06913 in}

End Of Sie

CRANKSHAFT INSPECTION

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1. Measure the crankshaft end play using a dial 

gauge.

• If it exceeds the maximum specification, 

replace the crankshaft or grind the thrust side 

of crankshaft and use the oversize thrust 

bearing so that the specified end play is 

obtained.

Standard crankshaft end play

0.08—0.29 mm {0.004—0.011 in}

Maximum crankshaft end play

0.30 mm {0.012 in}

Thrust bearing size

STD: 2.500—2.550 mm {0.0985—0.1003 in}

OS 0.25: 2.625—2.675 mm {0.1034—0.1053 

in}

2. Measure the runout of the main journal using a V-

block and dial gauge.

• If it exceeds the maximum specification, 

replace the crankshaft.

Maximum main journal runout

0.10 mm {0.0039 in}

3. Inspect the main journal diameter and crank pin 

diameter. Measurement positions total four and 

are in the X and Y directions, at two points (A and 

B) as shown in the figure.

• If it is not within the specification or if it 

exceeds the maximum off-round, grind the 

journal with an oversized bearing.

Standard main journal diameter

49.980—50.000 mm {1.9678—1.9685 in}

Maximum main journal off-round

0.005 mm {0.0002 in}

Standard crank pin diameter

49.980—50.000 mm {1.9678—1.9685 in}

Maximum crank pin off-round

0.005 mm {0.0002 in}

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A

B

X

Y

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MECHANICAL 

01-10–37

01-10

4. Inspect the main journal oil clearance using the following procedure:

(1) Install the thrust bearing, upper main bearing and crankshaft.

(2) Position a plastigauge on the journals.

(3) Install the lower main bearing and lower cylinder block. (See 01-10-40 CYLINDER BLOCK ASSEMBLY (I).)

(4) Remove the lower cylinder block. (See 01-10-22 CYLINDER BLOCK DISASSEMBLY (II).)

(5) Measure the main journal oil clearance.

• If it exceeds the maximum specification, 

replace the main bearing, or grind the 

main journal and use oversized bearings 

so that the specified oil clearance is 

obtained.

Standard main journal oil clearance

0.016—0.039 mm {0.0007—0.0015 in}

Maximum main journal oil clearance

0.084 mm {0.0033 in}

Main bearing size

STD: 2.489—2.510 mm {0.0980—0.0988 in}

OS 0.25: 2.614—2.617 mm {0.10292—0.10303 in}

OS 0.50: 2.739—2.742 mm {0.10784—0.10795 in}

End Of Sie

DUAL-MASS FLYWHEEL INSPECTION

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Caution

• Do not rework the dual-mass flywheel if it is distorted.

• Do not clean the dual-mass flywheel with any kind of fluid. Clean the dual-mass flywheel with a dry 

cloth only.

• Do not clean the gap between the primary and secondary mass. Only clean the bolt connection 

surface and the clutch surface.

Inspection Before Removal

1. Rotate the dual-mass flywheel or attempt to move 

it up and down, and left and right to verify that the 

center of the dual-mass flywheel does not move.

• If there is any movement as indicated by the 

arrows in the figure, replace the dual-mass 

flywheel.

2. Verify that the secondary mass does not rotate by 

15 teeth or more.

• If it rotates by 15 teeth or more, replace the 

dual-mass flywheel.

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MECHANICAL 

01-10–38

3. Measure the amount of guide pin projection of the 

dual-mass flywheel.

• If it exceeds the maximum amount, replace 

the dual-mass flywheel.

Dual-mass flywheel guide pin projection 

maximum amount

11.0—12.0 mm {0.434—0.472 in}

4. Using a dial indicator, measure the dual-mass 

flywheel runout.

• If it exceeds the maximum runout, replace the 

dual-mass flywheel.

Dual-mass flywheel maximum runout

1.5 mm {0.059 in}

Inspection After Removal

1. Visually inspect the dual-mass flywheel for crack.

• If there is any crack, replace the dual-mass flywheel.

2. Visually inspect the ring gear on the dual-mass flywheel for damage.

• If there is any damage, replace the dual-mass flywheel.

3. Visually inspect the surface that contacts the clutch disc for scratches, nicks, and discoloration.

• If there is any malfunction, replace the dual-mass flywheel.

Note

• Correct slight scratches and discoloration 

using sandpaper.

4. Visually inspect for grease leakage between the 

primary mass and secondary mass.

• If there is grease leakage, replace the dual-

mass flywheel.

End Of Sie

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MECHANICAL 

01-10–39

01-10

PILOT BEARING INSPECTION

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1. Without removing the pilot bearing, turn the 

bearing while applying force in the axial direction.

• If there is any malfunction, replace the pilot 

bearing.

End Of Sie

BOLT INSPECTION

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1. Measure the length of the each bolt.

• If it exceeds the maximum specification, 

replace the bolt.

Standard cylinder head bolt length

145.2—145.8 mm {5.717—5.740 in}

Maximum cylinder head bolt length

146.5 mm {5.768 in}

Standard connecting rod bolt length

43.7—44.3 mm {1.73—1.74 in}

Maximum connecting rod bolt length

 45.0 mm {1.77 in}

End Of Sie

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