Cylinder Bore

Piston-to-bore Clearance:

1. Using a bore gauge, measure cylinder bore for wear, out-of-round and taper.
Standard inner diameter: 89.000 - 89.030 mm (3.5039 - 3.5051 in)
Limit: 0.2 mm (0.008 in)

Out-of-round (X - Y):
Limit: 0.015 mm (0.0006 in)

Taper (A - B):
Limit: 0.010 mm (0.0004 in)

NOTE: If it exceeds the limit, rebore all cylinders. Replace cylinder block if necessary.

2. Check for scratches and seizure.
If seizure is found, hone it.

Piston Grade Numbers:

NOTE: If both cylinder block and piston are replaced with new ones, select piston of the same grade number punched on cylinder block upper surface.

Piston Skirt Diameter:

3. Measure piston skirt diameter.
Piston diameter "A". Specifications

Measuring point "a"
(Distance from the top):
Approximately 52 mm (2.05 in)

4. Check that piston-to-bore clearance is within specification.
Piston-to-bore clearance "B": 0.020 - 0.040 mm (0.0008 - 0.0016 in)

5. Determine piston oversize according to amount of cylinder wear.

NOTE: Oversize pistons are available for service. Refer to Specifications for Cylinder Block.

6. Cylinder bore size is determined by adding piston-to-bore clearance to piston diameter "A".
Rebored size calculation:
D = A + B - C

where,
D: Bored diameter
A: Piston diameter as measured
B: Piston-to-bore clearance
C: Honing allowance: 0.02 mm (0.0008 in)

7. To prevent distortion of cylinder bores in final assembly install main bearing caps, and torque to: 46 - 52 N-m (34 - 38 ft.lb.)

Tightening Sequence - Main Bearing Beam:

CAUTION: Tighten bearing cap bolts gradually in two or three stages. Start with center bearing and move outward sequentially.

8. Cut cylinder bores.

NOTE: When any cylinder needs boring, all other cylinders must also be bored. Do not cut too much out of cylinder bore at a time. Cut only 0.05 mm (0.0020 in) or so in diameter at a time.

9. Hone cylinders to obtain specified piston-to-bore clearance.
10. Measure finished cylinder bore for out-of-round and taper.

NOTE: Measurement should be done after cylinder bore cools down.