Mazda Engine LF, L3. Manual — part 7

MECHANICAL

01–10–11

01–10

Connecting Rod Cap Disassembly Note

1. Before removing connecting rod inspect the connecting rod side clearance. (See 01–10–20 CONNECTING

ROD INSPECTION.)

2. Remove the connecting rod bolt from the connecting rod cap by tapping the bolt with a plastic hammer.

Note

• The tappets are numbered to make sure they are assembled in their original positions. When removed,

keep the tappets with the cylinder head they were removed from. Do not mix the tappets.

Main Bearing Cap Disassembly Note

1. Before removing main bearing cap inspect the crankshaft end play. (See 01–10–19 CRANKSHAFT

INSPECTION.)

2. Loosen the main bearing cap bolts in two or three

steps in the order shown in the figure.

End Of Sie

CYLINDER HEAD INSPECTION

E5U011010100E01

1. Perform color contrast penetrate examination on the cylinder head surface.

• Replace the cylinder head if necessary.

2. Inspect for the following and repair or replace if necessary.

(1) Sunken valve seats
(2) Excessive camshaft oil clearance and end play

3. Measure the cylinder head for distortion in six

directions as shown in the figure.

• If it exceeds the maximum specification,

replace the cylinder head.

Cylinder head gasket contact surface

distortion (Maximum)

0.10 mm {0.004 in}

4. Measure the manifold contact surface distortion

as shown in the figure.

• If it exceeds the maximum specification, grind the surface or replace the cylinder head.

Manifold contact surfaces distortion (Maximum)

0.10 mm {0.004 in}

Manifold contact surfaces distortion (Maximum grinding)

0.15 mm {0.006 in}

9

8

7

5

4

3

1

2

10

6

B3E0110E067

B3E0110E008

IN

EX

C3U0110E003

MECHANICAL

01–10–12

End Of Sie

VALVE, VALVE GUIDE INSPECTION

E5U011012111E01

1. Measure the valve head margin thickness of each

valve.

• If it is less than the specification, replace the

valve.

Valve head margin thickness (Minimum)

IN: 1.62 mm {0.0637 in}
EX: 1.82 mm {0.0716 in}

2. Measure the length of each valve. Replace the

valve if necessary.

• If it is less than the specification, replace the

valve.

Valve length (Standard)

IN: 102.99—103.79 mm {4.055—4.086 in}
EX: 104.25—105.05 mm {4.105—4.135 in}

Valve length (Minimum)

IN: 102.99 mm {4.055 in}
EX: 104.25 mm {4.104 in}

3. Measure the stem diameter of each valve in X

and Y directions at the three points (A, B, and C)
as indicated in the figure.

• If it exceeds the specification, replace the

valve.

Valve stem diameter (Standard)

IN: 5.470—5.485 mm {0.2154—0.2159 in}
EX: 5.465—5.480 mm {0.2152—0.2157 in}

Valve stem diameter (Minimum)

IN: 5.440 mm {0.2142 in}
EX: 5.435 mm {0.2140 in}

4. Measure the inner diameter of each valve guide in

X and Y directions at the three points (A, B, and
C) as indicated in the figure.

• If not as specified, replace the valve guide.

Valve guide inner diameter (Standard)

5.509—5.539 mm {0.2169—0.2180 in}

MARGIN THICKNESS

IN : 33.5 mm {1.31 in}

EX : 28.3 mm {1.14 in}

C3U0110E051

L

B3E0110E068

X

Y

A

B

C

ADJ2224E024

X

Y

A

B

C

ADJ2224E026

MECHANICAL

01–10–13

01–10

5. Calculate the valve stem to guide clearance by

subtracting the outer diameter of the valve stem
from the inner diameter of the corresponding
valve guide.

• If it exceeds the specification, replace the

valve and/or the valve guide.

Valve stem to guide clearance (Standard)

IN: 0.024—0.069 mm {0.0009—0.0027 in}
EX: 0.029—0.074 mm {0.0012—0.0029 in}

Valve stem to guide clearance (Maximum)

0.10 mm {0.004 in}

6. Measure the protrusion height (dimension A) of

each valve guide without lower valve spring seat.

• If not within the specified, replace the valve

guide.

Valve guide protrusion height (standard)

12.2—12.8 mm {0.481—0.503 in}

End Of Sie

VALVE GUIDE REPLACEMENT

E5U011012111E02

Valve Guide Removal

1. Remove the valve guide from the combustion

chamber side using the SST.

Valve Guide Installation

1. Assemble the SSTs so that depth L is as

specified.

Valve guide protrusion height (standard)

12.2—12.8 mm {0.481—0.503 in}

VALVE STEM

VALVE GUIDE

CLEARANCE

ADA2224E027

A

VALVE GUIDE

CYLINDER HEAD

C3U0110E004

VALVE GUIDE

49 B012 015

C3U0110E005

L

49 L012 004A

49 L012 003A

49 L012 002A

B3E0110E071

MECHANICAL

01–10–14

2. Tap the valve guide in from the top of the cylinder

head until the SSTs contacts the cylinder head.

3. Verify that the valve guide protrusion height

(dimension A) is within the specification.

Valve guide protrusion height (standard)

12.2—12.8 mm {0.481—0.503 in}

End Of Sie

VALVE SEAT INSPECTION/REPAIR

E5U011010102E01

1. Measure the seat contact width.

• If not within the specification, resurface the

valve seat using a 45

° valve seat cutter and/or

resurface the valve face.

Valve seat contact width (Standard)

1.2—1.6 mm {0.048—0.062 in}

2. Verify that the valve seating position is at the

center of the valve face.
(1) If the seating position is too out side, correct

the valve seat using a 70

° (IN) or 65° (EX)

cutter, and a 45

° cutter.

(2) If the seating position is too inner side, correct

the valve seat using a 35

° (IN) cutter, and a

30

° (EX) cutter, and a 45° cutter.

3. Inspect the sinking of the valve seat. Measure the

protruding length (dimension L) of the valve stem.

• If not specified, replace the cylinder head.

Valve protrusion height (Standard)

IN: 40.64—42.24 mm {1.600—1.662 in}
EX: 40.50—42.10 mm {1.595—1.657 in}

49 L012 004A

49 L012 003A

49 L012 002A

VALVE GUIDE

B3E0110E072

A

VALVE GUIDE

CYLINDER HEAD

C3U0110E004

SEAT CONTACT
WIDTH

ADA2224E019

IN

70

°

45

°

35

°

EX

65

°

45

°

30

°

B3E0110E133

L

C3U0110E006