Content .. 8 9 10 11 ..

Mazda Engine SKYACTIV-G 2.5. Manual - part 10

MECHANICAL

01-10–24

Snap Ring Disassembly Note

1. Before removing the snap ring, verify that the large end of connecting rod drops under its own weight with no

resistance. (See 01-10-35 PISTON AND CONNECTING ROD INSPECTION.)

2. Remove the snap ring using a flathead

screwdriver.

Lower Cylinder Block Disassembly Note

1. Before removing the lower cylinder block, inspect the crankshaft end play. (See 01-10-36 CRANKSHAFT

INSPECTION.)

2. Loosen the lower cylinder block installation bolts

B in two or three passes in the order shown in the

figure and remove them.

3. Loosen the lower cylinder block installation bolts

A in two or three passes in the order shown in the

figure and remove them.

SNAP RING

bpe2ue00000022

ENGINE
FRONT

bpe1ze00000039

ENGINE
FRONT

bpe1ze00000040

MECHANICAL

01-10–25

01-10

4. Using a screwdriver wrapped in a cloth, peel the

sealant away a little at a time, and remove the

lower cylinder block.

Caution

• Do not apply excessive force to the

screwdriver. Otherwise, the lower

cylinder block could be damaged.

• Be careful not to scratch or damage the

seal surface. Otherwise, it could cause

oil leakage.

Thrust Bearing And Main Bearing Disassembly Note

1. The removed thrust bearings and main bearings are to be kept so that they can be assembled to the same

positions and in the direction as before removal.

Crankshaft Disassembly Note

Caution

• Placing the crankshaft on a disassembly bench will deform or damage it because the plate for the

crankshaft position sensor signal detection installed to the crankshaft is larger than the

counterweight. Therefore, set wood blocks or similar objects on the both sides of the crankshaft

so that the plate does not contact the disassembly bench directly when placing the crankshaft on

the bench.

End Of Sie

CYLINDER HEAD INSPECTION

id011000507100

1. Inspect the cylinder head surface for cracks and other damage using a red dye penetrant.

• If there is a malfunction, replace the cylinder head.

2. Measure the combustion chamber side of the

cylinder head for distortion in six directions as

shown in the figure using a straight edge and

feeler gauge.

• If the distortion exceeds the maximum

specification, replace the cylinder head. Do

not attempt to repair the cylinder head by

milling or grinding.

Maximum distortion, head gasket side of the

cylinder head

0.05 mm {0.002 in}

LOWER CYLINDER BLOCK

CLOTH

bpe2ue00000025

bpe1ze00000003

MECHANICAL

01-10–26

3. Inspect the contact surface of the exhaust

manifold and the intake manifold for distortion by

measuring as shown in the figure using a straight

edge and feeler gauge.

• If the distortion on the intake manifold side

exceeds the maximum specification, replace

the cylinder head.

• If the distortion on the exhaust manifold side

exceeds the maximum specification, grind the

surface or replace the cylinder head.

Maximum distortion, manifold side

IN: 0.10 mm {0.0039 in}

EX: 0.05 mm {0.002 in}

Maximum cutting length, manifold side

IN: Cutting not authorized

EX: 0.20 mm {0.0079 in}

End Of Sie

VALVE SEAT INSPECTION/REPAIR

id011000501300

1. Measure the contact width of the valve face and

the valve seat using the valve lapping compound.

• If it is not within the specification, resurface

the valve seat using the

45° valve seat cutter.

Standard valve seat contact width

1.37—1.84 mm {0.0540—0.0724 in}

Valve seat angle

45°

2. Verify that the area where the valve seat contacts

the valve face is centered.

• If the seating position is too high, correct the

valve seat using a

70° (IN) 70° (EX) valve seat

cutter and a

45° valve seat cutter.

• If the seating position is too low, correct as

follows:

—

IN: Correct the valve seat using a

20°

valve seat cutter and then using a

45°

valve cutter.

—

EX: Correct the valve seat using a

45°

valve seat cutter.

bpe1ze00000004

SEAT CONTACT
WIDTH

bpe1ze00000102

70°

45°

20°

70°

45°

VALVE SEAT

COMBUSTION CHAMBER

bpe1ze00000103

MECHANICAL

01-10–27

01-10

3. Inspect the valve seat for sinkage. Measure the

protruding length (dimension L) of the valve stem

using a valve of standard length.

• If it is not within the specification, replace the

cylinder head.

Standard valve seat sinkage amount

(Dimension L)

IN: 48.93—50.17 mm {1.927—1.975 in}

EX: 48.87—50.11 mm {1.925—1.972 in}

End Of Sie

VALVE, VALVE GUIDE INSPECTION

id011000506200

1. Measure the valve head margin thickness using a

vernier caliper.

• If it is less than the standard specification,

replace the valve.

Standard valve head margin thickness

IN: 1.75—1.95 mm {0.0689—0.0767 in}

EX: 1.95—2.15 mm {0.0768—0.0846 in}

2. Measure the length of the each valve using a

vernier caliper.

• If it is less than the minimum specification,

replace the valve.

Standard valve length

IN: 107.00—107.60 mm {4.2127—4.2362 in}

EX: 117.09—117.69 mm {4.6099—4.6334 in}

Minimum valve length

IN: 106.78 mm {4.2039 in}

EX: 116.87 mm {4.6012 in}.

3. Measure the valve stem diameter of each valve

using the micrometer. Measurement positions

total six and are in the X and Y directions, at three

points (A, B, and C) as shown in the figure.

• If it is less than the minimum specification,

replace the valve.

Standard valve stem diameter

IN: 5.470—5.485 mm {0.2154—0.2159 in}

EX: 5.465—5.480 mm {0.2152—0.2157 in}

Minimum valve stem diameter

IN: 5.424 mm {0.2135 in}

EX: 5.419 mm {0.2133 in}

bpe1ze00000104

MARGIN THICKNESS

IN : 34.0 mm {1.34 in}
EX : 29.0 mm {1.14 in}

bpe5ue00000012

bez0je00000017

bpe2ue00000084

Content .. 8 9 10 11 ..