Maintenance
0330−1/A1
RT-flex50-D
Wärtsilä Switzerland Ltd
19/ 25
Group
Key No.
Description Measuring
direction
(method of
measuring)
Nominal
dimension
(normal, new)
[mm]
Maximum clearance,
dimension
(due to wear)
[mm]
3403 Piston crown
1 Crown outer ∅
495
0
− 0.2
2 Crown outer ∅
497.7
0
− 0.2
3403
3425
Piston ring grooves
3 Height of the uppermost groove vertical
15
+ 0.38
+ 0.33
4 Height of the two lower grooves vertical
15
+ 0.33
+ 0.28
5 Groove depth radial 17.50
3425 Piston rings
Ring height vertical
15
0
− 0.03
6 Ring clearance vertical 0.33−0.41 0.63
7 Ring clearance vertical 0.28−0.36 0.58
*8 Ring width radial
16.5 ± 0.25
for Running-in Coated
(RC) piston ring see
diagram on page 18
3403 Piston skirt
9 Skirt outer ∅
499.4
−0
− 0.2
min. 497.7
3403 Piston rod
10 Rod outer ∅
200
− 0.050
− 0.096
min. 199.30
The ring width at positions A, B and C is the decisive criterion for refitting of used
piston rings.
Used piston rings may be refitted if they will keep within their min. ring width till the
next overhaul (for judging and reusing piston rings see also 3425−1).
* Pay attention to measuring point!
50−D / 2010
learance Table
iston and Piston Rings