43 44
45
46
47
8
A
511.0÷70.0 01.0÷70.0 11.0÷530.0 11,0÷70,0
B
80.0÷40.0 80.0÷50.0 90.0÷050.0 90,0÷50,0
C
70.0÷30.0 570.0÷40.0 780.0÷030.0 70,0÷30,0
225
315 350-400 440
- 34 -
DISASSEMBLY/REASSEMBLY
KD 225_315_350_400_440 Workshop Manual_cod. ED0053029330_1° ed_ rev.00
Piston rings, play between the slots (mm)
Replacethepistonorpistonringsifthevalueexceedsthemaximum
limit.
Piston rings, assembly order
A =1stChromiumplatedpistonring(nitridedfor225-350-400)
B =2ndpistonring(torsional)
C =3rdpistonring(oilscraper)(nitridedfor225-350-400)
D =Chromiumplatedzone
Note: Ifaword(top,orsomeotherword)iswrittenonthesurfaceof
apistonring,mountthatsurfaceupwards.
Beforeinsertingthepistonintothecylinder,oilandturnthepi-
stonringssothatthecutsarestaggered120°toeachother.
InKD350andKD225engines,thesecondpistonringisnot
torsional,whiletherstandthirdpistonringsdonothavechro-
miumplatedzonesbutarenitrided.
Lubricate the following parts with oil before mounting: the pi-
stonpin,thepiston,thecylinderandthebig-endbearing
Piston - Retting
Connect piston to connecting rod, lubricate piston pin and introduce
it into the piston/connecting rod assembly by exerting pressure with
yourthumb.
Fitbothpistonpincirclipsandcheckthattheyarewellseated.
When introducing both the connecting rod and the piston into the
cylindermakesurethatthelargercrownsurfaceA (ifcomparedtothe
combustionchamber)isonthesamesideasthepushrodopeningB.
Clearance
A =Clearance
C =Headgasket
Thethicknessofgasket Cdeterminestheclearance A,whichmustbe
0.45-0.55mmforKD315withinjectionpumpserialN°6590-259;itis
0.50-0.60mmwithinjectionpumpserialN°6590-281.
Theclearanceis0.45-0.55mmforKD225inallcases.
Theclearanceis0.50-0.60mmforKD350-400-440inallcases.
ForthecorrectthicknessofgasketCseetableing.49÷50.
There are gaskets with inner diameters oversized by 1 mm for KD
315andKD350,requiredifthecylindersareground.