WORKSHOP MANUAL - lombardini service

4
Disassembly / Reassembly
PISTON
Remove the connecting rod big end cap.
Remove the piston-connecting rod assembly.
Note: The combustion chamber is a Ricardo type.
81
82
Stop pin rings, dismounting and remounting
Extract the ring inserting a pointed tool in hollow A.
On remounting, insert rings with the points turned downwards inside
the corners ( α = 15°).
83
84
Piston, disassembly and inspection
Remove the stop rings and remove the pin (see fig. 83).
Remove the piston rings and clean the slot.
Measure diameter Q at height A from the base of skirt (A = 9 mm).
If the diameter is worn more than the 0.05 mm minimum given
value, replace piston and rings.
Note: The provided oversize elements are of 0.50 mm and 1.00 mm
85
Piston, class
The pistons are subdivided according to their diameters into categories: A, B, C. These references, are shown on the top of
the piston (see fig. 82).
Class Ø Cylinder - mm Ø Piston - mm Clearance - mm
A 74,990÷75,000
74,930÷74,940
B 75,000÷75,010
74,940÷74,950
0,050÷0,070
C 75,010÷75,020
74,950÷74,960
Piston supply:
Pistons at the nominal diameter are only supplied in category A.
Pistons oversized by 0.50 and 1.00 mm are supplied with reference to the increased level on the piston crown: Ø 75.5 – 76.0 .
- 42 - FOCS Workshop Manual_cod. 1.5302.858_1° ed_ rev. 00