Shibaura N843 - Cylinder Block

3-4 109823 2/09
4. Valve spring
a. Check the valve spring visually for damage.
b. Measure the squareness of the spring using a
square on a surface plate and replace if the
service limit is exceeded.
c. Check the free length and spring force with a
spring tester and replace if the service limit is
exceeded.
Reassembly
Reassemble components in the reverse order of
disassembly. When assembling the valve spring, retainer
and cotter, be especially careful not to damage the valve
guide seal. Tighten the glow plug to the proper torque—5.6-
10.5 lb
f
•ft(8-15 Nm) {0.8~1.5 kgf•m}.
Cylinder block
Inspection and service
1. Check for cracks, damage and distortion on the top
of the block in the same way as the cylinder head.
2. Measurement of cylinder bore
a. There should be no scratches, rust, corrosion, etc.
on the cylinder bore when checked visually.
b. Measure the cylinder bore at the top, center and
bottom respectively in the crankshaft direction (A)
and the direction at right angle to it (B). If the
repair value is exceeded, replace engine with long
block.
Standard
assembling
value
Service limit
Squareness in(mm) 0.047(1.2) More than
0.079(2)
Free length in(mm) 1.38(35) Less than
1.3(33.5)
Spring force (when
compressed to
1.20(30.4) in(mm))
17.9 lb
f
(79.8
N){8.1 kgfp}
Less than
15.4 lb
f
(68.6
N){7 kgf}
Distortion on cylinder block top surface in(mm)
Standard assembling value Repair value
Less than 0.0020(0.05) More than 0.0047(0.12)
Cylinder bore dia. ø in(mm)
3.0315-3.0322
(77-77.019)
More than 3.0394(77.2)
Fig. 3-12
Fig. 3-13
Squareness
Free Length
Replace with long block assembly
AB
Front
1
 Ring Sliding Range