WinGD WARTSILA RT-flex58T-D, Maintenance Manual

Page: 266 / 498

Maintenance
3425 − 1/A1
RT-flex58T-D
Winterthur Gas & Diesel Ltd.
2/ 7
2.1 Measure coating thickness with piston in situ (through scavenge ports)
Before each measurement the layer measurement tool 94356 must be calibrated.
Use the delivered calibration foils and the bare top flank of a spare top piston ring
as base material for proper setting.
⇒ Clean piston ring running surface at reachable measuring points P1 to P9.
⇒ Press the sensor of the layer measurement tool against the piston ring surface
at middle of ring height.
⇒ Measure the layer thickness and note the output value.
A
WCH01145
94356
2
1
MINIMUM
RECOMMENDED
MEASURING POINTS
ON PISTON RING
P3
P5
P7
P1 P9
P5
P1 P9
2.2 Wear rate
The chrome-ceramic coating is a lifetime coating. However, the actual wear de-
pends on operating conditions. When during a piston underside inspection a pis-
ton ring with a partially worn chrome-ceramic coating is found, we recommend
overhauling the unit at next opportunity (Fig. ’B’).
With regular done measuring you can determine the specific wear rate for each
piston ring.
The piston rings can still be used, if the remaining chrome-ceramic coating is
above the following limits:
− Uppermost piston ring ’a’ > 0.05 mm
− Lower piston rings ’b’ and ’c’ > 0.02 mm
Below those minimal coating thicknesses, a piston ring replacement must be
planned.
PARTIALLY WORN CC-COATING
B
2013-08
Checking Wear of Piston Rings and Ring Grooves with Four Piston Rings