22
COMPILER TECO/ATI
ENDORSED
DATE
23.06.2003
REG. CODE
1-5302-607
MODEL N°
50889
DATE OF ISSUE
06-03
REVISION
00
X
20
21
22
23
0,30
÷
0,50
0,25
÷
0,50
0,80
0,80
A = 0,22
B = 0,18
C = 0,16
0,003
÷
0,013
0,050
79,93
÷
79,958
84,910
÷
84,940
19,997
÷
20,002
21,997
÷
22,002
0,023
÷
0,038
0,023
÷
0,038
0,070
0,070
25LD330-2
25LD425-2
25LD330-2
25LD425-2
CHECKS AND OVERHAUL
Piston rings - Pistons - Piston pins
Check the wear of piston rings by fitting them into the cylinder
through the lower end and measuring the end gap (fig.20). The
values should be:
Check that the rings move freely in the grooves and check the ring/
groove clearance using a feeler gauge (fig.21).
If the clearance exceeds the values shown in the table, renew the
piston and the piston rings.
Piston rings must always be renewed after dismantling
the piston.
Piston diameter check: The diameter of the piston must be
measured at approximately 18 mm from the base (fig.22).
Fitting mm
Max. wear mm
Piston ring
1st Compression
2nd Compression
3rd Oil scrapper
Max. wear mm
Engine
Diameter mm
Check the clearance between cylinder and piston, if it is greater
than 0.120 mm both cylinder and piston must be replaced.
Assembly clearance between piston pin and piston in millimetres:
Fitting mm
Max. wear mm
Connecting rods
The connection between the connecting rod small end and the wrist
pin is without a bushing. Assembly clearance between connecting
rod small end and piston pin in millimetres:
Checking parallelism between the two axes of the connecting rod
(fig.23):
1. Fit the wrist pin in the hole in the small end of the connecting
rod and fit a calibrated pin into the big end (with bush fitted).
Engine
Ø Piston pin
mm
Assy.clearance
mm
Max wear
mm
Piston ring
Compression
Oil scrapper