Winterthur Gas X40-B, Maintenance Manual

Page: 293 / 495

Maintenance
3403 − 4/A1
Winterthur Gas & Diesel Ltd.
1/ 2
Top Surface − Check
Tools:
1 Feeler gage 94122
1 Template 94366
1 Template 94366A
1. General 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Procedure − Piston Removed 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. Procedure − Piston Installed 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. General
Each time you remove a piston, you must do a check of the top surface of the piston
head for damage (burn scars).
The causes of burn scars are as follows:
D
Poor combustion
D Worn nozzles
D Heavy local carbon particles on top of the piston head etc.
Note: You can also do this check with the piston installed.
2. Procedure − Piston
Removed
1) Put the template (94366, Fig. 1 ) in
position on the top piston ring (1).
2) Turn the template (94366) around the
axis of the piston head.
3) Use the feeler gage (94122) to measure
the depth of the burn scar(s).
4) Remove the template (94366).
Note: You can also use a depth gauge to
measure the depth of the burn
scar(s).
5) If the burn scar(s) are less than 5.0 mm,
do step a ) and step b ):
a) Use an applicable tool to grind the
burn scars.
b) Use emery paper to make sharp
edges smooth.
6) If the burn scars are more than 5.0 mm
deep, do step a ) to step c ):
a) Remove the piston crown, refer to
3403 − 3, paragraph 2
b) Use surface welding to repair the
piston crown to its original
thickness.
c) Assemble the piston, refer to
3403 − 3, paragraph 3 and
paragraph 4 .
Note: Before you start the engine, find the
cause of the burn scars.
Piston
2016
Fig. 1
Piston
Ring
94366
WCH03663
5.0 mm