54
Repair instructions
Piston and con. rod, inspection
Checking piston wear
Check the pistons for cracks, damaged piston ring
dowels and worn piston ring grooves. If the piston has
deep grooves on the skirt surface, the piston
(liner kit) must be scrapped. Likewise, if the piston
has one or several cracks in the gudgeon pin hole or
in the base of the combustion chamber. Cracks on the
edge of the piston crown around the combustion
chamber are generally of no consequence. Carry out a
crack test by means of the chalk dust test. If any kind
of damage has occurred, the injection equipment must
be checked as well.
Check the wear on the gudgeon pin. There must not
be any noticeable slack.
The gudgeon should have a light interference fit in the
piston when cold,
max. 0.004 mm
.
NOTE!
The cylinder liner wear must be checked be-
fore piston rings, small end bushings etc. are re-
placed.
Please refer to “Cylinder liner, inspection and mea-
surement” on page 57.
Removal of piston, small end
bush replacement
Special tools: 9991801, 9992071, 9992479 (7x series),
9992669 (6x series)
Before the small end bush is replaced, the con rod
must be checked for cracking, straightness and twist.
A cracked, bent or twisted con rod must be scrapped.
1
Remove the gudgeon pin retaining circlips and press
the gudgeon pin out with mandrel 9992071.
2
Use a new gudgeon pin and measure the con rod in a
jig.
The gudgeon pin may have the following tolerances:
A. Straightness: Max. 0.05 mm per 100 mm length.
B. Twist: Max. 0.1 mm per 100 mm length.
Содержание TAMD61A
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