!n many cases, a mechanic is justified in replacing
parts with new materiai rather than attempting repair.
However, there are times where a slight amount of
reworking or reconditioning may save a customer
considerable added expense. Crankshafts, valves and
other parts are in this category. For example, if a
cylinder is only slightly worn and within usable limits, a
honing operation to remove the glaze may make it
suitable for reuse with a standard size piston and new
piston rings, thereby saving the expense of new parts.
Various factors such as type of operation of the
unit, hours in service and next overhaul period must be
considered when determining whether new parts are
installed or used parts are reconditioned to provide
For convenience and logical order in disassembly,
the various subassemblies and other related parts
mounted on the cylinder block will be treated as
separate items in the various sections of the manual.
Before any major disassembly, the engine must be
drained of lubricating oil. Water and fuel, On engines
cooled by a heat exchanger the fresh water system and
raw water system must both be drained. Lubricating oil
should be drained from any power transmission
attached to the engine.
To perform a major overhaul or other extensive
repairs, the complete engine assembly, after removal
from the engine base and driven mechanism, should be
mounted on an engine overhaul stand; then the various
subassemblies should be removed from the unit. When
only a few items need replacement, it is not always
necessary to mount the engine on an overhaul stand.
Parts removed from an individual engine should
be kept together so they will be available for inspection
and assembly. Those items having machined faces,
which might be easily damaged by steel or concrete,
should be stored on suitable wooden racks or blocks or
a parts dolly.
The cleaning procedure used for all ordinary cast
iron parts is outlined under “Clean Cylinder Block” in
Section 1.1, while any special cleaning procedure will
be mentioned in the text wherever required.
Steam C leaning
A Steam cleaner is a necessary item in a large
shop and is most useful for removing heavy
accumulations of grease and dirt from the exterior of
the engine and its subassemblies.
Solvent Tank Cleaning
A tank of sufficient size to contain the largest part
which will require cleaning (usually the cylinder block)
must be provided and provisions made for heating the
cleaning solution to 180 degs. F.
This tank is filled with a commercial heavy-duty
solvent which is heated to the above temperature.
Large parts are lowered directly into the tank with a
hoist; smalt parts are placed in a wire mesh basket and
lowered into the lank. The parts are immersed in the
cleaning tank long enough to loosen all grease and dirt.
When lowering components into the tank mantlla
rope slings should not be used as the chemicals used in
degreasing tank will rot the rope enuring a possibility
that units could be dropped, it is advised that wire rope
slings are used.
WARNING: Caustic based solvents should not be
used for parts containing Aluminium. Check before
Another tank of similar size containing hot water
should be provided for rinsing the parts.
Before removal of subassemblies from the engine
(but after removal of the electrical equipment) the
exterior of the engine should be thoroughly cleaned,
ensure that exhaust and air intake are suitably sealed, if
steam cleaning is used. Then after each subassembly is
removed and disassembled, the individual parts should
Thorough cleaning of each part is absolutely
necessary before a part can be satisfactorily inspected.
Below are listed various items of equipment needed for
Parts may be dried with compressed air. The heat
from the hot tanks will quite frequently complete the
drying of parts without the use of air.
If parts are not to be used immediately after
cleaning, they should be dipped in suitable inhibiting
compound. Remove the rust proofing compound
before instaiing the part in an engine.