Engine Overhaul Manual
Jabiru Aircraft
Pty Ltd
Jabiru 2200 & 3300 Aircraft Engines
This document is controlled while it remains on the Jabiru server. Once this no longer applies the document becomes uncontrolled.
ISSUE
1
2
3
4
5
6 7
Dated : 28/10/2014
Issued By: AS
Page: 56 of 201
L:\files\Manuals_For_Products\Engine_Manuals\Overhaul_Manual\JEM0001-7_Overhaul_Manual_DRAFT_(29_10_14).docx
5.7 Cleaning
5.7.1 Materials and Processes
Two processes are involved in cleaning engine parts; degreasing to remove dirt and sludge (soft
carbon) which form the bulk of the cleaning required, and the removal of hard carbon by decarbonizing,
brushing or scraping and grit-blasting.
In many cases this manual recommends washing parts using Kerosene. In these cases any similar
suitable solvent (such as diesel fuel) may be used at the discretion of the overhauler.
5.7.2 Degreasing
Degreasing is best accomplished by immersing or flooding the part in kerosene or a suitable
commercial solvent such as Varsol or Perm-A-Chlor and agitating with a brush.
Overhaulers are warned against the use of any water-mixed degreasing solutions containing caustic
compounds or soap. Such compounds, in addition to being potentially harmful to aluminium, may
become impregnated in the pores of the metal and cause oil foaming when the engine is returned to
service.
5.7.3 Removal of hard carbon
While the degreasing solution will remove dirt, grease and soft carbon, deposits of hard carbon will
almost invariably remain on some interior surfaces. To facilitate removal, these deposits must first be
loosened by immersion in a decarbonising solution (usually heated). A variety of commercial
decarbonising agents are available, including products such as Redik DKT, Gunk, Penetrol, etc. Only
hydrocarbon based decarbonisers should be used: refer to the note above regarding water-mixed
degreasing solutions.
Decarbonizing will usually loosen most of the hard carbon deposits remaining after degreasing; the
complete removal of all hard carbon, however, generally requires brushing or scraping. All of these
operations demand care on the part of the mechanic to avoid damage to machined surfaces. In
particular, wire brushes and metal scrapers must never be used on any bearing or contact surface.
At the conclusion of cleaning operations, rinse the parts in petroleum solvent, water, dry and remove
any loose particles by air blasting. Apply a liberal coating of engine oil or other anti-corrosion product to
all steel surfaces.