Piston - Refitting; Piston Clearance; Connecting Rod - Kohler KD 625/3 Workshop Manual

4
Disassembly / Reassembly
61
63
65
- 36 -
62
64
66

Piston - Refitting

Caution – Warning
Lubricate the following parts with oil before mounting: the piston
pin, the piston, the cylinder and the big-end bearing
Connect piston to connecting rod in a way that the combustion cham-
ber center b is under nozzle tip a.
Lubricate piston pin and introduce it into the piston by exerting pres-
sure with your thumb.
Check that both circlips are well inside their seats.

Piston clearance

A = Clearance volume is 0,65 ÷ 0,7 mm for size S injectors and 0,55
÷ 0,6 mm for size P injectors
B = Copper seal with various thicknesses
The piston crown in the TDC (top dead centre) position may vary, and
extend or be short of the upper surface of the cylinder.
Use a dial indicator to measure the positive or negative difference
between the two surfaces (piston crown and upper cylinder surface)
and use a suitable thickness copper gasket B for the cylinder head
to adjust the clearance volume A between the cylinder head and the
piston crown, and which must be between 0,65 and 0,7 mm for size S
injectors and 0,55 ÷ 0,6 mm for size P injectors.
The table below shows how to choose the most suitable cylinder
head copper seal according to the position of the piston in relation to
the upper surface of the cylinder.

Connecting rod

Caution – Warning
When remounting the big-end bearings, remember to thoroughly
clean the parts and generously lubricate them to prevent seizure
when the engine is started up for the first time
Remove the oil sump and internal oil filter.
Remove connecting rocis and check as follows.
Important
All connecting rod/piston units should be fitted back into the
corresponding cylinders; mark them to avoid mistakes.

See page 35 fig. 71 for specifications as to the tightening of the
connecting rod big end bearing.
KD Workshop Manual_cod. ED0053029350_1° ed_ rev. 00
Seal thickness
Position