Cylinder Block - Yanmar 4LHA-HTP Operation Manual

Chapter 2 Basic Engine

2. Cylinder Block

2. Cylinder Block
The cylinder block is a thin-skinned,
short skirt type with rationally placed ribs. The side
walls are wave-shaped to maximize rigidity for
strength and low noise.
2-1 Inspection of parts
Make a visual inspection to check for cracks on engines
that have frozen up, overturned or otherwise been subject-
ed to undue stress. Perform a color check on any portions
that appear to be cracked, and replace the cylinder block if
the crack is not repairable.
2-2 Cleaning of oii holes
Clean all oil holes, making sure that none are clogged up
and the blind plugs do not come off.
Color check kit
Part code No. 97550-004560
(low-weight),
Quantity
Penetrant 1
Developer
2
Cleaner 3
2-3 Color check procedure
(1) Clean the area to be inspected.
(2) Color check kit
The color check test kit consists of an aerosol cleaner,
penetrant and developer.
(3) Clean the area to be inspected with the cleaner.
Either spray the cleaner on directly and. wipe, or wipe
the area with a cloth moistened with cleaner.
(4) Spray on red penetrant
After cleaning, spray on the red penetrant and allow
5 ~ 10 minutes for penetration. Spray on more red
penetrant if it dries before it has been able to penetrate.
(5) Spray on developer
Remove any residual penetrant on the surface after the
penetrant has penetrated, and spray on the developer.
If there are any cracks in the surface, red dots or a red
line will appear several minutes after the developer
dries.
Hold the developer 300 ~ 400mm (11.8110 ~ 15.7480in.)
away from the area being inspected when spraying,
making sure to coat the surface uniformly.
(6) Clean the surface with the cleaner.
NOTE: Be sure to read the instructions
check kit before
2-9
, 4LHA Sen
for the color
use.