CYLINDER BLOCK — Inspection (Cont'd) / Crankshaft

EM-49prose procedure

Source page misprints "instructions" as "intructions" in step 8; transcribed verbatim as printed.

Inspection (Cont'd)

3
Measure piston skirt diameter. Piston diameter "A": 70.980 - 71.010 mm (2.7945 - 2.7957 in). Measuring point "a" (Distance from the bottom): 9.5 mm (0.374 in).
SEM012D
4
Check that piston-to-bore clearance is within specification. Piston-to-bore clearance "B": 0.010 - 0.030 mm (0.0004 - 0.0012 in).
5
Determine piston oversize according to amount of cylinder wear.
Oversize pistons are available for service. Refer to S.D.S.
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
Install main bearing caps, and tighten to the specified torque to prevent distortion of cylinder bores in final assembly.
8
Cut cylinder bores.
When any cylinder needs boring, all other cylinders must also be bored.
Ensure that boring machines intructions are closely followed.
9
Hone cylinders to obtain specified piston-to-bore clearance.
10
Measure finished cylinder bore for out-of-round and taper.
Measurement should be done after cylinder bore cools down.

Specification	Value
Piston diameter "A" — StandardMeasuring point 9.5 mm from bottom	70.980 - 71.010 (2.7945 - 2.7957)mm (in)
Piston measuring point "a" (distance from bottom)Reference dimension	9.5 (0.374)mm (in)
Piston-to-bore clearance "B"Standard	0.010 - 0.030 (0.0004 - 0.0012)mm (in)
Honing allowance "C"Used in D = A + B − C	0.02 (0.0008)mm (in)

Piston diameter "A" — StandardMeasuring point 9.5 mm from bottom

70.980 - 71.010 (2.7945 - 2.7957)mm (in)

Piston measuring point "a" (distance from bottom)Reference dimension

9.5 (0.374)mm (in)

Piston-to-bore clearance "B"Standard

0.010 - 0.030 (0.0004 - 0.0012)mm (in)

Honing allowance "C"Used in D = A + B − C

0.02 (0.0008)mm (in)

1
Check crankshaft main and pin journals for score, wear or cracks.
2
With a micrometer, measure journals for taper and out-of-round. Out-of-round (X − Y): Less than 0.005 mm (0.0002 in). Taper (A − B): Less than 0.002 mm (0.0001 in).
SEM316A

Specification	Value
Crankshaft journal out-of-round (X − Y)Limit	Less than 0.005 (0.0002)mm (in)
Crankshaft journal taper (A − B)Limit	Less than 0.002 (0.0001)mm (in)

Crankshaft journal out-of-round (X − Y)Limit

Less than 0.005 (0.0002)mm (in)

Crankshaft journal taper (A − B)Limit

Less than 0.002 (0.0001)mm (in)