Lombardini CHD series - Precombustion Chamber and Tappets; Precombustion chamber; Hydraulic tappet valve control; Hydraulic diagram for feeding the tappets

- 34 - Workshop Manual LDW CHD _ cod. 1.5302.345 - 6° ed_rev. 05
A
120,32÷000,32
640,0÷040,0 01,0
B
579,22÷069,22
4
36
35
33
31
34
32
Precombustion chamber
The precombustion chamber can be extracted from the head banging
with a punch into the hole from the injector housing.
This procedure implies irreversible damages to the precombustion
chamber which will have to be replaced. In the assembly stage
line up the dowel 1 with the reference notch 2 located in the head.
Driving must be carried out evenly
The clearance allowance between the precombustion chamber
and its bore on the cylinder head is equal to 0.05 mm.
Using a depth gauge check that the precombustion chamber
plane protrusion does not exceed 0.04 and does not receed
over 0.02 mm from the head plane level.
The precombustion chamber plugs of the CHD PLUS series engines
have a different internal volume from the CHD series; therefore,
they are not interchangeable.
Disassembly / Reassembly
Hydraulic tappet components:
a) Tappet body
b) Plunger
c) Non-return valve
d) Spring
e) Push rod
f) Low-pressure chamber
g) High-pressure chamber
The hydraulic tappet is a device that enables elimination of
clearance between timing system components and provides the
following advantages:
- Reduces noise levels during operation.
- Reduces wear of the timing system components, thanks to there
being no collisions at the opening with consequent breaking of
theoillm.
- No maintenance.
Hydraulic diagram for feeding the tappets
1 Rocker-arm pin
2 Rocker arm
3 Push rod
4 Oil drainage
5 Hydraulic tappet
Hydraulic tappet valve control
Nota: If tappet is worn out along diameter B replace it.
No oversize tappets are available. If tappet/camshaft
surface is worn - replace
Clearance
(mm)
Limit value
(mm)
Dimensions
(mm)
Ref.