Opel Frontera UBS. Manual - part 253

 

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Opel Frontera UBS. Manual - part 253

 

 

6A–79

ENGINE MECHANICAL

015RV014

The size mark (1) for piston outside diameter is
represented as shown in illustration below.

Outside Diameter
Size Mark A : 93.360 mm–93.370 mm

(3.6756 in–3.6760 in)

Size Mark B : 93.371 mm–93.380 mm

(3.6760 in–3.6764 in)

Size Mark C : 93.381 mm–93.390 mm

(3.6764 in–3.6768 in)

015RS025

Measure the cylinder bore inside diameter (refer to
“Cylinder Block” in this manual).

012RS002

Piston Rings (8)

Any worn or damaged part discovered during engine
overhaul must be replaced with a new one.

1. Ring end gap measurement

D

Insert the piston ring into the bore.

D

Push the ring by the piston, at a right angle to the
wall, into the point at which the cylinder bore
diameter is the smallest.

D

Measure the ring end gap.

Compression Ring

1st ring

Standard:

0.300 mm–0.400 mm

(0.0118 in–0.0157 in)

Limit:

1.0 mm (0.0394 in)

2nd ring

Standard:

0.450 mm–0.600 mm

(0.0177 in–0.0236 in)

Limit:

1.2 mm (0.0472 in)

Oil ring

Standard:

0.150 mm–0.450 mm

(0.0059 in–0.0177 in)

Limit:

1.05 mm (0.0413 in)

6A–80

ENGINE MECHANICAL

015RS026

D

Positioning mark (1) is painted as shown in the
illustration.

Marked T : No.1 Compression ring

Marked T2 : No.2 Compression ring

015RS027

2. Measure the clearance between the piston ring

groove and the piston ring with a feeler gauge. If the
piston ring groove / piston ring clearance exceeds the
specified limit, the piston must be replaced.

Compression Ring Clearance
Standard : 0.016 mm–0.038 mm

(0.0006 in.–0.0015 in)

Limit : 0.15mm (0.0059 in)

015RS028

Piston Pin (9)

NOTE: Do not reuse the old piston pin.

1. Use a micrometer to measure the new piston pin

outside diameter in both directions at three different
positions.

2. Measure the inside diameter of the connecting rod

small end. If the fitting interference between the small
end and pin does not conform to the specified value,
the connecting rod must be replaced.

Standard : 0.023 mm–0.038 mm (0.0009
in–0.0015 in)

015RS029

3. Insert the new pin into the piston and rotate it. If the

pin rotates smoothly with no backlash, the clearance
is normal. If there is backlash or roughness, measure
the clearance. If the clearance exceeds the specified
limit, the piston must be replaced.

Clearance
Standard : 0.010 mm–0.017 mm

(0.0004 in.–0.0007 in)

Limit : 0.040 mm (0.0016 in)

6A–81

ENGINE MECHANICAL

Connecting Rods (11)

1. Check the connecting rod alignment If either the bend

or the twist exceeds the specified limit, the connecting
rod must be replaced.

Bend per 100 mm (3.937 in)
Limit: 0.15 (0.0059)
Twist per 100 mm (3.937 in)
Limit: 0.20 (0.0078)

015RS030

2. Measure the connecting rod thrust clearance. Use a

feeler gauge to measure the thrust clearance at the
large end of the connecting rod If the clearance
exceeds the specified limit, the connecting rod must
be replaced.

Standard : 0.16 mm–0.35 mm

(0.0063 in.–0.0138 in)

Limit : 0.40 mm (0.0157 in)

015RS031

3. Measure the oil clearance between the connecting

rod and the crankshaft.
1. Remove the connecting rod cap nuts and the rod

caps (12).
Arrange the removed rod caps in the cylinder
number order.

2. Clean the rod bearings and the crankshaft pins.

3. Carefully check the rod bearings. If even one

bearing is found to be damaged or badly worn, the
entire bearing assembly must be replaced as a
set. Reinstall the bearings in their original
positions. Apply plastigage to the crank pin.

015RS032

6A–82

ENGINE MECHANICAL

4. Reinstall the rod caps (12) to their original

positions.
Tighten the rod cap nuts.

Torque: 54 N·m (5.5 Kg·m/40 lb ft)

NOTE: Do not allow the crankshaft to rotate.

5. Remove the rod caps.

6. Measure the width of the plastigage and

determine the oil clearance. If the oil clearance
exceeds the limit, replace the rod bearing as a
set.

Standard : 0.019 mm–0.043 mm

(0.0007 in–0.0017 in)

Limit : 0.08 mm (0.003 in)

015RS008

7. Clean the plastigage from the bearings and the

crankshaft pins.

Con–rod Bearing Selection

Select and install the new connecting rod bearings,
paying close attention to the connecting rod big end
diameter size mark (1).

NOTE: Take care not to confuse the alignment mark (2)
and the size mark (1) during the installation procedure.

015RS034

1 Size Mark

Big end Bore 

Diameter

Crankshaft Pin 

Diameter

Connecting Rod

Bearing Thickness

(Reference)

Color of

Size

Mark

Oil Clearance 

(Reference)

A

56.994-57.000

(2.2439-2.2441)

1.512-1.516

(0.0595-0.0597)

Yellow

0.025-0.054

(0.0010-0.0021)

B

56.988-56.994

(2.2436-2.2439)

53.922-53.937

(2.1229-2.1235)

1.508-1.512

(0.0594-0.0595)

Green

0.027-0.056

(0.0011-0.0022)

C

56.982-56.988

(2.2434-2.2436)

1.504-1.508

(0.0592-0.0594)

Pink

0.029-0.058

(0.0011-0.0023)

Reassembly

1. Install connecting rod
2. Install piston

3. Install piston pin

D

Apply a thin coat of engine oil to the piston pin. Try to
insert the piston pin into the piston pin hole with
normal finger pressure.

NOTE: When  changing piston / connecting rod
combinations, do not change the piston / piston pin
combination and do not reuse the old piston pin.

 

 

 

 

 

 

 

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