CHAPTER 708.

01-4OD
Bearings
PAGE 1(1)

1. General Bearing Requirements 2. Bearing Metals

and Criteria
2.1 Tin based White Metal
Bearings are vital engine components; Tin-based white metal is an alloy with mini-
therefore, the correct bearing design and mum 88% tin (Sn), the rest of the alloy
the proper choice of bearing metal is ne- composition is antimony (Sb), copper (Cu),
cessary for reliable engine performance. cadmium (Cd) and small amounts of other
elements that are added to improve the
Bearing design criteria depend on the bear- fineness of the grain structure and homo-
ing type and, in general, on: geneity during the solidification process.
This is important for the load carrying and
a) Bearing sliding surface geometry. sliding properties of the alloy. Lead (Pb)
. content in this alloy composition is an irnpu-
rity, as the fatigue strength deteriorates with
b) The surface roughness of the journal or
' pin, which determines the permissible increasing lead content, which should not
, bearing pressure and required oil film exceed 0.2 % of the cast alloy composition.
thickness. This is necessary to ensure
effective and .safe functioning of the Tin based white metal is used in the main
bearing. bearings, crankpin bearings, crosshead
bearings, guide shoes, camshaft bearings
c) The correct flow of cooling oil to pre- and thrust bearings because of its excellent
vent heat accumulation, which is ob- load carrying and sliding properties.
tained through a flow area, provided
either through the clearance between 2.2 Tin Aluminium (AISn40)
the journal and the bearing bore or
through axial grooves in the bearing Tin aluminium is a composition of alumi-
sliding surface (see ltem 5.3 concern- nium (Al) and tin (Sn) where the tin is trap-
ing grooves a?d wedges). ped in a 3-dimensional mesh of aluminium.
I AISn40 is a composition with 40% tin. The
The compactness of engines and the en- sliding properties of this composition are
gine ratings influence the magnitude of the very similar to those of tin based white
specific load on the bearing and make the metal but the loading capacity of this mate-
correct choice of bearing metals, production rial is higher than tin based white metals for
quality and, in certain bearings, the applica- the same working temperature; this is due
tion of overlayer an absolute necessity. to the ideal combination of tin and alumi-
(See ltem 3). nium, where tin gives the good embedability
and sliding properties, while the aluminium
Scraping of the bearing surfaces is strictly mesh functions as an effective load absor-
prohibited, except in those repair situations ber.
mentioned in Items 7.7 and 7.10. it is
strongly recommended to contact MAN Tin aluminium is used in main bearings and
B&W Disesl for advice before starting any crosshead bearing lower shells.
repairs, as incorrect scraping has often
proved to have an adverse effect on the 3. Overlayers
sliding properties of the bearing, and has
resulted in damage. An overlayer is a galvanic coating of 90%
lead (Pb) and 10% tin (Sn), which is applied
directly on to the white metalltin aluminium
sliding surface of the bearing; the thickness
 CHAPTER 708,0240
Bearings
PAGE I(*)

of the coating is 0.02-0.03mm. The over- shells to create bore reliefs. Their main ob-
layer is a soft and ductile coating, its main jective is to compensate for misalignments
objective is to ensure good embedability which could result in a protruding edge
and conformity between the bearing sliding (step) of the lower shell's mating face to
' surface and the pin surface geometry..
that of the upper shell. Such a protruding
edge can act as an oil scraper and cause
4. Flashlayer, Tin (Sn) oil starvation. Main bearing (Plates 70801,
70802). and crankpin bearing (Plate
A flash layer is a 100% tin (Sn) layer which 70804).
is applied galvanically; the thickness of this
layer is from 2 w to 5 W . The coating of 5.3 Axial Oil Grooves and Oil Wedges
tin flash is applied all over and functions (Plates 70803, 70806, FigA-A)
primarily to prevent corrosion (oxidation) of Qil grooves and wedges have the following
the bearing. functions:
The tin flash also functions as an effective
dry lubricant when new bearings are instal- a) To enhance the oil distribution over the
led and the engine is barred. load carrying surfaces. (The tapered
areas give improved oil inlet condi-
tions).
5. Bearing Design
(Plates 70801, 70802, 70803, 70804) b) Especially in the case of crosshead
bearings (Plate 70803) - to assist the
Plain bearings for MC engines are manu- formation of a hydrodynamic oil film
factured as steel shells with a sliding sur- between the load carrying surfaces.
face of white metal or tin aluminium. Tin
aluminium bearings are always of the thin c) To provide oil cooling (oil grooves).
shell design while the white metal bearings
can either be of the thick shell or thin shell In order to perform these functions, the oil
design. must flow freely from the lubricating
I grooves, past the oil wedges, and into the
The bearing surface is furnished with a supporting areas - where the oil film carries
centrally placed oil supply groove and other the load.
i
design features such as tangential run-outs,
oil wedges and/or bore reliefs. 5.4 Thick Shell Bearings
(Plate 70801)
5.1 Tangential Runout
(Plates 70801, 70802, 70804, Fig. B-6) This type of bearing has a steel back with
the required stiffness
A tangential runout is a transition geometry
between the circumferential oil supply a) To ensure against distortion of the
groove and the bearing sliding surface. This sliding surface geometry, and
special oil groove transition geometry pre-
vents an oil scraping effect and reduces the b) To support the cast-on white metal in
resistance to the flow of oil towards the regions where the shell lacks support,
loaded area of the bearing (Main bearing for example in the area of the upper
Plates 70801, 70802 and crankpin bearing shell mating faces.
Plate 70804).
The top clearances in this bearing design
5.2 Bore Relief are adjusted with shims, while the side
70801, 70802, 708041 Fig. A-A) clearances are a redetermined result of
m e bearing sliding surface is machined at the summation of 'the housing bore, shell
the mating faces of the upper and lower wall thickness, journal tolerances, and the
 CHAPTER 708.03-40D

a influence of the staybolt tensioning force For new thin shell bearings and new/
which deforms the bedplate around the overhauled thick shell bearings the
bearing assembly. clearances must lie within the limits
specified in the maintenance manual
5.5 Thin Shell Bearings (see Volume 11, 904 and 905).
(Plate 70802)

Thin shell bearings have a wall thickness 2. as an indicator to determine the condi-
between 2% and 2.5% of the journal dia- tion of the bearingata periodic check
meter. The steel back does not have the without opening up, see ltem 7.1,
sufficient stiffness to support the cast-on Checks without openin-up '
white metal alone. The bearing must there-
fore be supported rigidly over its full length. The stated maximum top clearance
This type of bearing is manufactured with- does not influence the functioning of
a circumferential overlength (crushlnip) the bearing nor does it have any rela-
which, when the shells are mounted and tion to the wear limit rejection criteria
tightened up, will produce the required for bearings (see ltem 7. 8: Bearing
radial pressure between the shell and the Wear Rate).
bearing housing.
In both cases, it is vital that the clearance
The maximumlminimum top clearance in values from the previous check are avail-
this shell is predetermined and results from able for comparison.Therefore, it is neces-
a summation of the housing bore, shell wall sary to enter clearances in the engine log
thickness, journallpin diameter tolerances book with the relevant date and engine
and, for main bearings, the deformation of sewice hours (see e.g. Plate 70813).
the bedplate from the staybolt tensioning
force. 5.7 Wear
\ .
5.6 Top Clearance Under normal service conditions, bearing
3 wear is negligible. Excessive wear is due to
Correct top cleafance in main bearings, abrasive or corrosive contamination of the
- crankpin hearings, and crosshead bearings
is necessary to sustain the required oil flow
system oil which will affect the roughness of
the journallpin and increase the wear rate
through the bearing, and hence stabilize the of the bearing. (Item 7.8 Bearing Wear
i bearing temperature at a level that will Rate).
ensure the fatigue strength of the bearing
metal. In the main and crankpin bearings, 5.8 Undersize Bearings
the clearance ensures the necessary space
to accommoc~atethe journal orbit so as to a) Crankwin bearings are thin shell bear-
avoid mechanical overload tendencies on ings, with a relatively long production
the bearing sliding surface (especially in the time; therefore, to ensure delivery in
main bearing). the case of an emergency, the engine
builder has a ready stock of semi-pro-
The bearings are checked in general by duced shells (blanks) that cover a
measuring the top clearances. range from nominal diameter to 3 mm
undersize, see also ltem 6.4. Semi-
In sewice, clearance measurements can be produced shells for journals with under-
regarded: sizes lower than 3 mm are not stocked
as standard. Furthermore, undersizes

- 1. as a check of the correct re-assembly

of the bearing.
lower than 3 mm can also involve modi-
fication such as the bolt tension, hy-
draulic tool,.etc.
 7
CHAPTER 708.04-4013
Bearings
HEIW INDUBTRES PAGE 1(1)

For advice on the application of under- 6.2 Spark Erosion

size bearings, it i s recommended to
contact MAN 6.5W Diesel. Spark erosion is caused by a voltage dis-
charge between the main bearing and jour-
.b) The ' n bearinas for the MC engine nal surface.
series can be of the thick or thin. shell
type (see 70801, 70802); the informa- The cause of the potential is the develop-
tion under point a) is also valid here. ment of a galvanic element between the
ship's hull, sea water, and the propeller
c) Crosshead bearing~are only available shaftlcrankshaft.
as standard shells, as the recondition-
ing proposal for offset grinding of the The oil film acts as a dielectric. The punc-
pin (refer to 6.4 b) 2) facilitates the use
of standard shells.
ture voltage in the bearing depends on the
thickness of the oil film.
-
It is recommended to contact MAN
B& W Diesel for advice on such recondi-
With increasing engine ratings, the specific
tioning. load in the main bearing is increased. This
will reduce the oil film thickness, and en-
able the discharge to take place at a lower
voltage level.
6.1 Surface Roughness Since the hydrodynamic oil film thickness
varies through a rotation cycle, the dis-
Journallpin surface roughness is important charge will take place at roughly the same
for the bearing condition. instant during each rotation cycle, i.e when
Increased surface roughness can be the film thickness is at its minimum. The
caused by: roughening will accordingly be concentrated
in certain areas on the journal surface.
; a) Abrasive damage due to contamination
of the system oil. See also ltem 7.4 b). In the early stages, the roughened areas
I
can resemble pitting erosion - but later, as
b) Corrosive damage due to sea water the roughness increases, the small craters
contamination of the system oil (acidic) will scrape off and pick up white metal -
i or oxidation of the journals due to con- hence the silvery white appearance.
densate. See also ltem 7.4 b).
Therefore, to ensure protection against
c) Spark erosion (only in main bearings). spark erosion, the potential level must be
See also ltem 6.2. kept at maximum 80 mV, which is feasible
today with a high efficiency earthing device.
With increasing journaVpin roughness, a If an earthing device is installed, its effect-
level will be reached where the oil film iveness must be checked regularly. Spark
-hickness is no longer sufficient, causing erosion is only observed in main bearings
netal contact between journallpin and the and main bearingjournals. Regarding repair
bearing sliding surface. This will cause of the journals, see ltem 7.11.
white metal to adhere to the journallpin,
giving the surface a silvery white appear- The condition of the bearings must be eva-
ance. When such a condition is observed, luated to determine whether they can be
the journallpin must be reconditioned by reconditioned or have to be discarded.
polishing, and the roughness of the surface It is recommended to contact MAN B&W
made acceptable. In extreme cases, the Diesel if advice is required.
joumallpin must be ground to an undersize
(see undersizejoumalwpins, ltem 6.4).
 P CHAPTER 708.05-40D
Bearings
HEAW INWSTRIES PAGE 1(1)

6.3 Surface Geometry

7. Practical Information
~ " r f a c e geometries such as roundness
defect, conicity, barrel form, and misalign- 7.1 Check without Opening up
ment may give rise to operational difficul-
ties. Such abnormal cases of journaltpin Follow the check list in accordance with the
geometry and misalignment may Occur after programme stated in Vol. I 'Maintenance',
a repair. 904 and 905. Enter the results in the engine
I t is recommended to contact MAN B&W log book. See also Item 7.12 'Inspection of
Diesel for advice. bearings:

6.4 Undersize JournaldPins a) Stop the engine and block the main
starting valve and the starting air distri-
fl-
In case of severe damage, .it may become. butor.
necessary to recondition the journallpin by
grinding to an undersize. The final under- b) Engage the turning gear.
size should as far as possible be selected
2s a half or full millimetre. This is advisable c) Just afler stopping the engine, while the
in order to simplify production and availabi- oil is still circulating, check that uniform
lity of undersize bearings for emergencies, oil jets appear from all the oil outlet
as for example in the following cases: grooves in the crosshead bearing lower
shell and the guide shoes. The oil flow
t a) Main and crankpin journals can be from the main and crankpin bearings
ground to 3 mm undersize; undersize must be compared from unit to unit;
journals below this value require spe- there should be a similarity in the flow
cial investigations of the bearing as- patterns.
\ . sembly.
It is recommended to contact MAN d) Turn the crankthrow for the relevant
3 B&W Diesel for advice. cylinder unit to BDC position and stop
the lube oil circulating pump.
b) In service, crodsheads pins can be:
r
e) 1. Check the top clearance with a feel-
- 0.15 mm)
1. Polished to (DnOminal er gauge. The change in clearances
i as the minimum diameter. must be negligible when compared
with the readings from the last in-
2. Offset to a maximum of 0.3 mm spection (overhaul).
and ground.
2. For guide shoe and guide strip
In both cases, since standard bearings clearances and checking procedure,
are used, the bearing top clearances see Vol. I :'Maintenance', 904.
will increase depending on the surface
condition of the pin to be reconditioned. f) Examine the sides of the bearing shell,
The offset value used for grinding must guide shoes and guide strips, and
be stamped clearly on the pin. check for squeezed-out or loosened
I t i s recommended to contact M A N metal; also look for white metal frag-
B&W Diesel for advice. ments in the oil pan.
 Bearings CHAPTER
PAGE
708.0640D
1(1)
-
g) In the following cases, ihe bearings ing surface. The white metal in the
must be dismantled for inspection, see damaged area is seen clearly with a
ltem 7.2: sharply defined overlayer border. This
defect is regarded as a cosmetic de-
fect, if it is confined to small areas of
1. Bearing running hot. the bearing surface without intercon-
nection.
2. Oil flow and oil jets uneven, reduced
or missing. b) W i ~ i n aof overlaver manifests itself by
parts of the overlayer being smeared
3. Increase of clearance since previous out. Wiping of overlayer can take place
reading larger than 0.05 mm. when running-in a new bearing; how-
See also ltem 7.8 ever, if the wiping is excessive, the

4. White metal squeezed ' out, dis-

lodged or missing at the bearing,
- cause must be found and rectified. One
of the major causes of wiping is pin1
journal surface roughness.
7

' guide shoe or guide strip ends..

c) White metal w i ~ i n gis due to metal
If Items 1 is observed in crosshead bearings contact between the sliding surfaces
or crankpin bearing, measure the diameter which causes increased frictional heat,
of the bearing bore in several positions. If resulting in plastic deformation (wiping)
the diameter varies by more than 0.06 mm, (see ltem 7.4).
send the connecting rod complete to an
authorised repair shop. 7.4 Causes for Wiping

If Items 1. 3 or 4 are observed when in- a) Hard Contact Spots, e.g. originating from:
specting main bearinas, we will recommend
\ . to inspect the two adjacent bearing shells, 1. Defective pinljournal, bearing, or
crosshead guide surfaces.
3 to check for any abnormalities.

7.2 Open up 1nspectio)l and Overhaul

(Plate 70849)
2. Scraped bearing or guide shoe sur-
faces.
. - ~

3. Hard particles trapped between the

-
Note: Record the hydraulic pressure level housing bore and the back of the
when the nuts of the bearing cap go loose. shell.

Carefully wipe the running surfaces of the 4. Fretting on the back of the shell and
pinljournal
. . and the bearing shell with a in the housing bore.
clean rag. Use a powerful lamp for inspec-
tion. b) Increased pinljournal surface rough-
ness.
Assessment of the metal condition and
journal surface is made in accordance with In most cases the increase in rough-
the directions given below. The results ness will have occurred in service, and
should be entered in the engine log book. is attributed to:
See also ltem 7.12, 'Inspection of bearings:
1. Hard particle ingress:
7.3 Types of Damage
Hard particle ingress may be due to
The overlay er and white metal the malfunction of filters and/or
can exhibit the following types of damage. centrifuges or loosened rust and
7
scales from the pipings.
a) Tearina of the overlaver is due to sub- Therefore, always pay careful atten-
standard bonding. The damage is not tion to oil cleanliness.
confined to specific areas of the bear-
 ,--
Bearings CHAPTER 708.07-~OD
HUW HIXISTRIES PAGE l(1)

i 2. Corrosive attack: b) Crack development after a short work-

ing period may be due to a misalign-
If the oil develops a week acid. ment (e.g. a twist between the bearing
cap and housing) or geometric irregula-
It strong acid anhydrides are rities (e.g. a step between the contact
added to the oil which; in combi- faces of the bearing shell, or incorrect
nation with water, will develop oil wedge geometry).
acid.
c) High local loading: for example, if, dur-
If the salt water content in the ing running-in, the load is concentrated
lube oil is higher than 1%. The on a few local high spots of the white
water will attack the white metal. metal.
and result in formation of a ver;
,- hard black tin-oxide encrustation. Note: Bearings with cracks cannot be re-
(SnO) which mav scratch and paired.
roughen the pin suiace.
The formation of tin oxide is inten- 7.7 Repair of Oil Transitions
sified by rust from the bottom (Wedges, tangential run out and
tank. Therefore, keep the internal bore relief) .
surface, especially the "ceiling",
clean. Note: It is strongly recommended to contact
MAN B&W Diesel for advice before starting
t c) Inadequate lube oil supply. any repairs.

d) Misalignment. Formation of sharp ridges or incorrect incli-

nation of the transition to the bearing sur-
face will seriously disrupt the flow of oil to
7.5 Cracks
the bearing surface, causing oil starvation
Crack development is a fatigue phenome- at this location.
3
non due to increased dynamic stress levels
in local areas of thq bearing metal. Oil transitions are reconditioned by carefully
.7 cleaning for accumulated metal with a
In the event of excessive local heat input, straight edge or another suitable tool. Oil
the fatigue strength of the white metalltin wedges should be rebuilt to the required
6 aluminium will decrease, and thermal inclination (maximum 11100) and length,
cracks are likely to develop at the normal see Plate 70803.
dynamic stress level.
A small cluster of hairline cracks develops Note: Check the transition geometries be-
into a network of cracks. At an advanced fore installing the bearings, see Item 14.
stage, increased notch effect and the influ-
ence of the hydrodynamic oil pressure will 7.8 Bearing Wear Rate
tear the white metal from the steel back and
produce loose and dislodged metal frag- The reduction of shell thickness in the load-
ments. ed area of the main, crankpin and cross-
head bearing in a given time interval repre-
7.6 Cause for Cracks sents the wear rate of the bearing. Average
bearing wear rate based on service experi-
a) Insufficient strength of the bonding ence is 0.01 mm/10,000 hrs. As long as the
between the white metal and the steel wear rate is in the region of this value, the
back (tinning or casting error). bearing function can be regarded as nor-
. mal. See also Item 7.1, point g).3
 HEAW INOUIITREJ
Bearings CHAPTER
PAGE
708.084OD
1(1)
--
For crosshead bearings, the .wear limit is a) 1. Overlayer wiping in crosshead bear-
confined to about 50% reduction of the oil ing lower shells is not serious, and
wedge length, see Plate 70803. Of course, is remedied by careful use of a
if the bearing surface is still in good shape, scraper.
.the shell can be used again after the oil
wedges have been extended to normal 2. Hard contact on the edges of cross-
length. Check also the pin surface condi- head bearings is normally due to
tion, see ltems 6.1 and 7.9. galvanic build-up of the overlay.
This is occasionally seen when
Far further advice, please contact MAN inspecting newly installed bearings
B& W Diesel A'S. and is remedied by relieving these
areas with a straight edge or an-
7.9 Surface Roughness (journaVpin)
other suitable tool.
a) Limits to surface rouahness
. 7

The surface roughness of the journal1 b) White metal squeezed out or wiped:
pin should always be within the speci- 1. The wiped metal can accumulate in
fied limits. the oil grooves1 wedges, tangential
run-out or bore relief where it forms
1. For main and crankpin journals: ragged ridges. such bearings can
I New journals 0.8 Ra normally be used again, provided
II Roughness approaching 1.6 Ra that the ridges are carefully removed
(journal to be reconditioned). with a suitable scraping tool and the
t
original geometry is re-established
2. For crosshead pins: (see ltem 7.7). High spots on the
I New or repolished 0.05 Ra bearing surface must be levelled out
II Acceptable in service 0.05-0.1 Ra by light cross-scraping.
\ . III Repolishing if over 0.1 Ra
2. In cases of wiping where the bearing
; b) Determination of the pin1 surface geometry is to be re-estab-
journal rouahness ! lished, it is important:
7
Measure the roughness with an elec- I to assess the condition of the
tronic roughness tester, or damaged area and, if found ne-
i
cessary, to check the bearing
Evaluate the roughness with a Ruko surface for hairline cracks under
tester, by comparing the surface of the a magnifying glass and with a
pinljournal with the specimens on the penetrant fluid, if necessary.
Ruko tester. When performing this test,
the pin surface and the Ruko tester II to check the surface roughness
must be thoroughly clean and dry. Hold of the journallpin.
the tester close to the surface and
compare the surfaces. If necessary, 3. In extreme cases of white metal
use your finger nail to run over the wiping, the oil wedges in the cross-
pinljournal surface and the Ruko speci- head bearing may disappear. In that
mens to compare and determine the event, the shell should be replaced.
roughness level.
c) For evaluation and repair of spark ero-
7.10 Repairs of Bearings on the Spot sion damage, refer to ltem 6.2.
7

Note: It is strongly recommended to contact d) Cracked bearina metal surfaces cannot

MAN B&W Diesel for advice before starting be repaired. The bearing must be re-
any repairs. placed (see Items 7.5 and 7.6).
 CHAPTER 708.09-40D
Bearings
HEAVY V I O U S ~ I E S PAGE 1(1)

;
7.11 Repairs of Journalk/Pins applied to the rope at regular inter-
vais. During the polishingoperation,
Crosshead c ins the rope must move slowly from one
Pin surface roughness should be less end of the pin to the other.
than 0.1 Ra (see ltem 7.9).If the Ra
value is higher than 0.1 pm, the pin can The polishing is continued until the
often be repolished on the spot, as roughness measurement proves that
described below. If the pin is also scrat- the surface is adequately smooth
ched, the situation and extent of the (see ltem 8.4).
scratched areas must be evaluated. If
there are also deep scratches, these This is a very time consuming ope-
must be levelled out carefully with 3M ration and, depending on the sur-
polishing paper, or similar, before the face roughness, about three to six
polishing process is started. . hours may be needed to complete
the polishing.
Use a steel ruler, or similar, to support
b) Journals
the polishing' paper, as the fingertips (Main and crankpin journals)
are too~flexible.
1. The methods for polishing of cross-
The surface roughness after .polishing head pins can also be used here,
should be 0.05 Ra. and method 1) Polishing with micro-
finishing film, will be the most suit-
The following methods are recommend- able method. A 30 micron micro-
ed for repolishing on the spot. finishing film is recommended here.

1. Polishina with microfinishinafilm 2. Local damage to the journal can

The polishing process is carried out also be repaired. The area is to be
with a "microfinishing film", e.g. 3M ground carefully and the transitions
aluminium oxide (30 micron and 15 to the journal sliding surface are to
micron), which can be recom- be rounded carefully and polished.
mended as a fairly quick and easy We recommend to contact MAN
method, although the best solution B& W Diesel for advice before such
will often be to send the crosshead a repair is carried out.
ashore.
7.12 Inspection of Bearings
The microfinishing film can be slung
around the pin and drawn to and fro Regarding check o f bearings before
by hand and, at the same time, installation, see item 14.
moved along the length of the pin,
or it is drawn with the help of a hand For the ship's own record and to ensure the
drilling machine; in this case, the correct evaluation of the bearings when
ends of the microfilm are connected advice is requested from MAN B&W Diesel,
together with strong adhesive tape. we recommend to follow the guidelines for
inspection, which are stated in Plates
2. Braided hemp roDe method 70809 - 70814.
This method is executed with a See the example of an Inspection Record
braided hemp rope and jeweller's on Plate 70813.
rouge.

A mixture of polishing wax and gas

oil (forming an abrasive paste of a
suitably soft consistency) is to be
 Bearings CHAPTER
PAGE
708.1M O D
1(1)
-
, 8. Crosshead Bearing ~ss'ernbl~ installed bearing types, Plate 70801,and
(See Vol. I ,'Components: housing assemblies, Plate 70805).
Plate 90401)
9.1 The Thick Shell Bearing Assembly,
.8.1 Bearing Type (Plate 70805,Fig. 1)

The type of bearing used in the crosshead The tensioning force of a thick shell bear-
assembly is a thin shell (insert) bearing ing assembly (Fig. 1) is transferred from the
(see ltem 5.5).The lower shell is a trimetal bearing cap (pos. 1) to the upper shell (pos.
shell, i.e. the shell is composed of a steel 2) and via its mating faces to the lower
back with cast-on white metal and an over- shell (pos. 3).
layer coating. The upper shell is a bimetal
shell, as it does not have the overlayer
coating; both the upper and lower.shells are
The bearing bore is equipped with the fol- ,
lowing geometry:
protected against corrosion with tin flash
(see ltem 4).
a) central oil supply groove and oil inlet in
8.2 B&aringFunction and Configuration the upper shell which ends in a tangen-
:
tial run-out (Item 5.1.) in both sides of
Because of the oscillating movement ,and the lower shell, see Plate 70801.
low sliding speed of the crosshead bearing,
the hydrodynamic oil film is generated b) the bearing bore is furnished with a
t through special oil wedges (see Item 5.3) bore relief (Item 5.2) at the mating
on either side of the axial oil supply faces of the upper and lower shell, see
grooves situated in the loaded area of the Plate 70801 .
bearing. The oil film generated in this man-
ner can be rather thin. This makes the de- 9.2 The Thin Shell (Insert Bearing)
> .
mands for pin surface roughness and oil Bearing Assembly
?. , wedgegeometry very important parameters (Plate 70805,Fig. 2)
for the assembly to fuvction. A further re-
quirement is effective moling which is en- This is a rigid assembly (Fig. 2). The bear-
. . sured by the transverse oil grooves. The ing cap (pos. 1) which has an inclined ver- 7

pin surface is superfinished (see ltem 7.9a) tical and horizontal mating face, is wedged
i 2).The lower shell is executed with a spe- into a similar female geometry in the bed-
cial surface geometry (embedded arc) plate (pos. 2), which, when the assembly is
which extends over a 120 degree arc, and pretensioned, will ensure a secure locking
ensures a uniform load distribution on the of the cap in the bedplate.
bearing surface in contact with the pin. The
lower shell is coated with an overlayer (see The lower shell is positioned by means of
ltem 3),which enables the pin sliding geo- screws (Pos. 3). During mounting of the
metry to conform with the bearing surface. lower shell it is very important to check that
the screws are fully tightened to the bed-
plate. This is to prevent damage to the
9. Main Bearings screws and shell during tightening of the
bearing cap. See also Vol. I , Maintenance,
The MC engine series can be equipped with 905.
'Thick shell bearings" (Item 5.5) or
'Thin shell bearings" (Item 5.4). See also ltem 5.5 earlier in this section.
For information regarding inspection and
The bearing type, i.e. "thick shell" or 'thin repair, see ltem 7.
shell" determines the main bearing housing
assembly described below (see table of
r
Bearings CHAPTER 708.1I - ~ O D
HEAW INDUSTRIES PAGE l(1)

10. Crankpin Bearing ~ s s e m b l ~ shims between the list and the guide
. (See Vol. I,'Components', shoe.
Plate 90401)
The sliding surfaces of the guide shoes
This assembly is mounted with a thin shell, and guide strips are provided with cast-
and has two or four tensioning'studs, de- on white metal and furnished with
pending on the engine type. Crankpin bear- transverse oil supply grooves and wed-
ing assemblies with four studs must be ges (see ltem 5.3, Plate 70803 and
tensioned in parallel, for example first the Plate 70806).
two forward studs and then the two aftmost
studs; the tensioning may be executed in For inspection of guide shoes and
two or three steps. This procedure is re- guide strips, see ltem 7.1, 7.3 c) and
7.4 a) 1 and a) 2 and Vol. 1, 'Mainten-
commended in order to avoid a twist (angu-
lar displacement) of the bearing cap to the
n?ating face on the connecting rod.
- ance', 904.

The oil supply groove transition to the bear- 12. Thrust Bearing Assembly
ing sliding surface is similar to that of the (Plate 70807)
main bearing geometry.
For information regarding inspection and The thrust bearing, which is integrated into
repair, see ltem 7. the chain drive, is a tilting-pad bearing of
the Michell type. There are eight pads (seg-
11. Guide Shoes and Guide Strips ments) placed on each of the forward and
(Plate 70806) aft sides of the thrust collar. They are held
(See also Vol. P, 'Components', Plate in place circumferentially by stops. The
90401) segments can be compared to sliding
blocks and are pivoted in such a manner
a) The w i d e shoes, which are mounted that they can individually take up the angle
on the fore a?d aft ends of the cross- of approach necessary for a hydrodynamic
head pins, sli6e between guides and lubricating wedge. The lubricatinglcooling
transform the translatory movement of oil is sprayed directly on to the forward and
the pistonlpiston rod via the connecting aft sides of the thrust collar by means of
rod into a rotational movement of the nozzles positioned in the spaces between
crankshaft. the pads. The nozzles are mounted on a
semicircular delivery pipe.
The guide shoe is positioned relatively
to the crosshead pin with a positioning For clearances and max. acceptable wear,
pin screwed into the guide shoe, the see Vol. I , 'Maintenance', 905.
end of the ~ositionina in orotrudes
into a hole 'in the crosshead pin and
restricts the rotational movement of the 13. Camshaft Bearing Assembly
crosshead pin when the engine is turn- (Plate 70808)
ed with the piston rod disconnected.
The camshaft bearing assemblies are posi-
The guide strips are bolted on to the tioned between the exhaust and fuel cams
inner side of the guide shoes and en- of the individual cylinder units. The bearing
sure the correct position of the piston assembly is of the underslung design, i.e.
rod in the fore-and-aft direction. This the shaft rests in rigid bearing caps that are
P
alignment and the clearance between bolted from below to the horizontal face in
the guide strips and guide is made with the cam housings. The correct position of
the caps is ensured by dowel pins.
 7
CHAPTER 708.12-40D
Bearings
HEAW INWSTRES PAGE l(1)

The bearings used are of the thin shell type 14.2 Check Measurements
without overlayer (Item 5.5) and the shell
configuration can be: Place the shell freely, as illustrated in Plate
70827,Fig. I.
a) a two-shell assembly (upper and lower
shell), Plate 70808, Fig. 1. Measure the crown thickness, with a ball
micrometer gauge. Measure in the centre
b) a one-shell assembly (lower shell only), line of the shell, 15 millimetres from the
Plate 70808, Fig. 2. forward and aft sides.

In case b) the mating faces of the lower Record the measurements as described in
shell rest against the horizontal partition ltem 7.12 and Plates 70809-70814.
face in the cam housing. The wall thickness 7
at the mating faces of the shell is reduced T6is will facilitate the evaluation of the
to ensure that the inner surface of the shell bearing wear during later overhauls.
is flush with the bore in the cam hou'sing.
14.3 Cautions
The transition to the bearing sliding surface
is wedge-shaped; this is to ensure un- As the bearing shells are sensitive to defor-
restricted oil supply to the bearing sliding mations, care must be taken during hand-
surface. ling,transport and storage, to avoid dam-
aging the shell geometry.
The specific load in the camshaft bearings
is low, and the bearings function trouble The shells should be stored resting on one
free provided that the camshaft lub. oillUni side, and be adequately protected against
Lube system is well maintained, see page corrosion and mechanical damage.
708.27. However, if practical information is
needed, refer to ltem 7, 'Check without Preferably, keep new bearing shells in the
opening up' and 'Open up inspection and original packing, and check that the shells
overhaul'

'Maintenance', 906 .
I
For clearances, please refer to Vol. 1 ,
are in a good condition, especially if the
packing shows signs of damage. -
During transport from the store to the en-
gine, avoid any impacts which could affect
14. Check of Bearings the shell geometry.
before installation (Plate 70827)

Clean the bearing shells thoroughly before

inspecting.

14.1 Visual Inspection

a) Check the condition of the bearing

surfaces for impact marks and burrs.

b) Check that the transition between the

bore relief and the bearing sliding sur-
face is smooth.
 ,- Alignment of Main Bearings CHAPTER 708.13-40D
HUW WDUSTRIES PAGE l(1)

1. Alignment made under nearly the same temperature

3
and load conditions.
During installation of the engine, inter-
mediate shaft and propeller shaft, the yard It is recommended to record the actual
aims to carry out a common alignment, to jacket water and lub. oil temperatures and
ensure that the bearing reactions are kept load condition of the ship in Plate 70815.
within the permitted limits, with regard to
the different factors which influence the In addition, they should be taken while the
vessel and engine during sewice. ship is afloat (i.e. not while in dry dock).

Factors like the ship's load condition, per- Procedure

manent sag of the vessel, movements in
- sea, wear of bearings etc., makes it neces-
sary to regularly check the alignments:
Turn the crankpin for the cylinder con-
cerned to Pos. B1, see Fig. 2. Place a dial
gauge axially in the crank throw, opposite
Main bearings, see Items 2;1-2.6 the crankpin, and at the correct distance
Engine bedplate, see ltem 2.7 from the centre, as illustrated in Fig. 1. The
' Shafts, see ltem 2.8. correct mounting position is marked with
punch marks on the crankthrow. Set the
dial gauge to "Zero".
2. Alignment of Main Bearings
Take the deflection readings at the posi-
Plates 70815, 7081 7 tions indicated in Fig. 2.

The bearing alignment can be checked by "Closing" of the crankthrow (compression

deflection measurements (autolog) as de- of the gauge) is regarded as negative and
scribed in the following Section. "Opening" of the crankthrow (expansion of
the dial gauge) is regarded as positive, see
Example; If two adjacent main bearings at Fig. 1.
the centre of the engine are placed too
high, then at this 'point the crankshaft cen- Since, during the turning, the dial gauge
treline wilt be lifted to form an arc. This will cannot pass the connecting rod at BDC, the
cause the intermediate crank throw to de- measurement for the bottom position is
flect in such a way that it "opens" when calculated as the average of the two adja-
turned into bottom position and "closes" in cent positions (one at each side of BDC).
top position.
When taking deflection readings for the
Since the magnitude of such axial lengthen- three aftmost cylinders, the turning gear
ing and shortening increases in proportion should, at each stoppage, be turned a little
to the difference in the height of the bear- backwards to ease off the tangential pres-
ings, it can be used as a measure of the sure on the turning wheel teeth. This pres-
bearing alignment. sure may otherwise falsify the readings.

2.1 Deflection Measurements (autolog) Enter the readings in the table Fig. 3. Then
calculate the BDC deflections, 112 (B,+B,),
Plate 708 15 and note down the result in Fig. 4.

. - As the alignment is influenced by the tem-

perature of the engine and the load condi-
tion of the ship, the deflection measure-
Enter total "vertical deflections" (opening -
closing) of the throws, during the turning
from bottom to top position in the table Fig.
ments should, for comparison, always be 5(T-B).
 7
Alignment of Main Bearings CHAPTER 708.14-~OD
HEAW INWSTRIES PAGE 1(1)

i 2.2 Checking the ~eflections' 2.4 Causes of Crankshaft Deflection

Plate 70817 and page 701.14
1. Wear of main bearing
The results of the deflection measurements
.(see Plate 70815, Fig. 5 ) should be eva- 2. Displacement of bedplate
luated with the testbed measuremenrs (re- (see 'Piano Wire Measurements' )
corded by the engine builder on page
710. If re-alignment has been carried 3. Displacement of engine alignment and/
out later on (e. g.following repairs), the or shafting alignment.
results from these measurements should be
used. This normally manifests itself by large

. .
Values of permissible "vertical deflections"
etc. are shown in Plate 70817. '
alteration in the deflection of the aft-
most crank throw (see Shafting Align-
ment). ,

2.5 Piano Wire Measurements

-
~eviaion from earlier measurements may
be due to: A 0.5 mm piano wire is stretched along
- human error each
-*
side of the bedplate:
- journal eccentricity, The wire is loaded with 40 kp horizontal

t
- the causes mentioned in ltem 2.4
force.
furtheron \
At the centreline of each cross girder the
distance is measured between the wire and
2.3 Floating journals the machined faces of the bedplate top
outside oil groove.
> . See also Item 2.2 and Plate 70817.
3 It will thus be revealed whether the latter
Use a special bearing feeler gauge to in- has changed its position compared with the
vestigate the contact between the main reference measurement from engine instal-
bearing journa!~ and the lower bearing lation.
shells. Check whether the clearance be-
tween journal and lower shell is zero. 2.6 Shafting Alignment
i

If clearance is found between journal and This can be checked by measuring the load
lower bearing shell, the condition of the at:
shell must be checked and, if found dam-
aged, it must be replaced - the aftermost main bearing

The engine alignment should be checked - the intermediate shaft bearings

and adjusted, if necessary. (plummer blocks)

To obtain correct deflection readings in - in the stern tube bearing.

case one or more journals are not in con-
tact with the lower shell, it is recommended Taking these measurements normally re-
to contact the engine builder. quires specialist assistance.

As a reliable evaluation of the shafting

alignment measurements requires a good
basis, the best obtainable check can be ,
made if the yard or repairshop has carried
out the alignment based on precalculation
of the bearing reactions.
 ,- Circulating Oil and Oil System CHAPTER 708.15-400
HEAVV INWSTRIES PAGE l(1)

i
1. Circulating Oil Pump(4) draws the oil from the bottom tank
, (Lubricating and cooling oil) and forces it through the lub. oil cooler (5),
the filter (6), (with an absolute fineness of
Rust and oxidation inhibited engine oils, of 50 rrn (0.05 mm), corresponding to a nomi-
. the SAE 30 viscosity grade, should be nal fineness of approx. 30 r m at a retaining
chosen. rate of 90%) and thereafter delivers it to the
engine via three flanges: Y,U and R.
In order to keep the crankcase and piston
cooling space clean of deposits, the oils Via the camshaft booster pumps, oil is
should have adequate dispersancyldeter- supplied to camshaft bearing, roller
gency properties. guides and exhaust valve actuators.

Alkaline circulating oils are generally supe- The main part of the oil is, via the tele-
r
rior in this respect. . scopic pipe, sent to the piston cooling
manifold, where it is distributed be-
fhe international brands of oils listed below tween piston cooling and bearing lubri-
have all given satisfactory service in one or cation. From the crosshead bearings,
more MAN B&W diesel engine installa- the oil flows thrpugh bores in the con-
tion(~). necting rods, to the crankpin bearings.

The remaining oil goes to lubrication of

the main bearings, chain drive and
thrust bearing.

BP Energol OE-HT30 The relative amounts of oil flowing to the

Castrol Marine CDX 30 piston cooling manifold, and to the main
\ . Chevron Veritas 800 Marine bearings, are regulated by the butterfly
3 . Exxon EXXMAR XA valve (7), or an orifice plate.
Fina Fina Alcano 308

. - Mobil

Texaco
i Mobilgard 300
Melina 30130s
Doro AR 30
The oil distribution inside the engine i s
shown on Plate 70819 and 70824.

i Circulating Oil Pressure:

See Chapter 710.
The list must not be considered complete,
and oils from other companies may be
equally suitable. 3. Circulating Oil Failure

Further information can be obtained by 3.1 Cooling Oil Failure

contacting the engine builder or MAN B&W
Diesel NS,Copenhagen. The piston cooling oil is supplied via the
telescopic pipe fixed to a bracket on the
crosshead. From here it is distributed to the
2. Circulating Oil System crosshead bearing, guide shoes, crankpin,
Plates 708 18A,70819 and 70824 bearing and to the piston crown.

For engine without Uni-Lube system, see Failing supply of piston cooling oil, to one
r Plates 708188 and 70819 or more pistons, can cause heavy oil coke
deposits in the cooling chambers. This will
result in reduced cooling, thus increasing
 7
Circulating Oil and Oil System CHAPTER 708.16-40D
HEAW INWSTRIES PAGE 1(1)

the material temperature above the design Feel over 15-30 minutes after starting,
level. . again one hour later, and finally also after
reaching full load (see also 'Checks during
In such cases, to avoid damage to the pis- starting', Check 9 'Feel-over sequence' ,
'ton crowns, the cylinder loads should be Chapter 703).
reduced immediately (see slow-down be-
low), and the respective pistons pulled at
the first opportunity, for cleaning of the
cooling chambers.

Cooling oil failure will cause alarm and

slow-down of the engine. See Chapter 710.

For CPP-plants with a shaft 'generator

coupled to the grid, an auxiliary engine will
be started automatically and coupled to the
grid before the shaft generator is discon-
nected and the engine speed reduced.
See Plate 7031 1, ' Sequence Diagram'.

After remedying a cooling oil failure, it must

be checked (with the circulating oil pump
running) that the cooling oil connections in
the crankcase do not leak, and that the oil
outlets from the crosshead, crankpin bear-
ings, and piston cooling, are in order.

3.2 Lubricating Oil Failure

If the lub. oil pressure falls below the pres-

sures stated in- Chapter 710, the engine's
safety equipment shall reduce the speed to
SLOW DOWN level, respectively stop the
engine when the SHUT DOWN oil pressure
level has been reached.

For CPP-plants with a shaft generator

coupled to the grid, an auxiliary engine will
be started automatically and coupled to the
grid before the shaft generator is discon-
nected and the engine speed reduced.
See Plate 7031 1, ' Sequence Diagram'.

Find and remedy the cause of the pressure

drop.

Check for traces of melted white metal in

the crankcase and oil pan (see also Checks
A 1 and A2, Chapter 702).
 r
Maintenance of the circulating Oil CHAPTER 708.17-~OD
HEAW INDUSTRIES PAGE I(1]

j 1. Oil System Cleanliness In addition, particles may also appear in the

circulating oil coolers, and therefore we
In a new oil system, as well as in a system recommend that these are also thoroughly
which has been drained owing to repair or cleaned.
oil change, the utmost care must be taken
to avoid the ingress and presence of abra- 2.2 Flushing Procedure,
sive particles, because filters and centri- Main Lub. Oil System
fuges will only remove these slowly, and
some are therefore bound to find their way Regarding flushing of the camshaft lube oil
into bearings etc. pipes:

For this reason - prior to filling-up the Engines with Uni-Lube system, see
system - careful cleaning of pipes, coolers
r

and bottom tank is strongly recommended.

'
'
Camshaft lubrication for engines
with Uni-Lube system ltem 3.

Engines without Uni-Lube system,

2. Cleaning the Circulating see Separate camshaft lube oil
Oil System :
system ltem 2.3.

The recommendations below are 'based on However, experience has shown that both
our experience, and laid out in order to give during and after such general cleaning,
yards and operators the best possible ad- airborne abrasive particles can still enter
vice regarding the avoidance of mishaps to the circulating oil system. For this reason it
a new engine, or after a major repair. is necessary to flush the whole system by
continuously circulating the oil - while by-
The instruction given in this book is an passing the engine bearings, etc.
abbreviated version of our flushing proce-
dure used prior to shoptrial. A copv 'of the This is done to remove anv remainina ., abra-
complete fiushin procedure is available sive particles, and, before the oil is again
.r
d
through MAN B& or the engine builder. led through the bearings, it is important to
definitely ascertain that the system and the
2.1 Cleaning before filling-up oil have been cleaned adequately.
i

In order to reduce the risk of bearing dam- During flushing (as well as during the
age, the normal careful manual cleaning of preceding manual cleaning) the bearings
the crankcase, oil pan, pipes and bottom must be effectively protected against the
tank, is naturally very important. entry of dirt

However, it is equally important that the The methods employed to obtain effective
system pipes and components, between the particle removal during the oil circulation
filter@) and the bearings, are also carefully depend upon the actual plant installations,
cleaned for removal of "welding spray" and especially upon the filter(s) type, lub. oil
oxide scales. centrifuges and the bottom tank layout.

If the pipes have been sand blasted, and Cleaning is carried out by using the lub. oil
thereafter thoroughly cleaned or "acid- centrifuges and by pumping the oil through
washed", then this ought to be followed by the filter. A special flushing filter, with fine-
c "washing-out" with an alkaline liquid, and ness down to 10 pm, is often used as a
immediately afterwards the surfaces should supplement to or replacement of the system
be protected against corrosion. filter.
 CHAPTER 708.18-40D
Maintenance of the circulating Oil
H U W INDUSTRES PAGE 111)

, The following items are by-passed by such a level that the pressure in the cooler
blanking off with special blanks: is kept low.
a) The main bearings
b) The crossheads In order to obtain a representative control of
c) The thrust bearing the cleanliness of the oil system during
d) The chain drive flushing, "control bags" are used (e.g. 100
e) The turbocharger(s) (MAN B&W,MET) mm wide by 400 mm long, but with an area
f) The axial vibration damper of not less than 1000 cmz, and made from
g) The torsional vibration damper 0.050 mm filter gauze). Proposals for
(if installed) checkbag housings are shown on Plate
h) The moment compensators (if installed) 70821.
See also Plates 70820, 70821.
To ensure cleanliness of the oil system
It is possible for dirt to enter the crosshead after the filter, two bags are placed in the
bearings due to the design of the open system, one at the end of the main lub. oil
beariig cap. It is therefore essential to line for the telescopic pipes, and one at the
cover,the bearing cap with rubber shielding end of the main lub. oil line for the bear-
throughout the flushing sequence. ings.

As the circulating oil cannot by-pass the To ensure cleanliness of the oil itself, an-
bottom tank, the whole oil content should other bag is fed with circulating oil from a
t partake in the flushing. connection stub on the underside of a hori-
zontal part of the main pipe between circu-
During the flushing, the oil should be heat- lating oil pump and main filter. This bag
ed to 60-65t3 and circulated using the full should be fitted to the end of a 25 mm pla-
capacity of the pump to ensure that all stic hose and hung in the crankcase.
< . protective agents inside the pipes and com-
- 3 ponents are removed. At i n t e ~ a l sof approx. two hours, the bags
are examined for retained particles, where-
It is essential to obtain $n oil velocity which after they are cleaned and suspended
causes a turbu!ent flow in the pipes that are again, without disturbing the oil circulation 7
being flushed. in the main system.
i
Turbulent flow is obtained with a Reynold The oil flow through the "control bags"
number of 3000 and above. should be sufficient to ensure that they are
continuously filled with oil. The correct flow
"
Re= -x 1000, where
v
is obtained by restrictions on the bag sup-
ply pipes.
Re = Reynold number
V =Average flow velocity (mls) The max. recommended pressure differen-
v = Kinematic viscosity (cSt) tial across the check bag is 1 bar, or in
D = Pipe inner diameter (mm) accordance with information from the check
bag supplier.
The preheating can be carried out, for in-
On condition that the oil has been circu-
stance, by filling the waterside of the circu-
lated with the full capacity of the main
lating oil cooler (between the valves before
pump, the oil and system cleanliness is
and after the cooler) with fresh water and
judged sufficient when, for two hours, no
then leading steam into this space. During abrasive particles have been collected.
the process the deaerating pipe must be >
open, and the amount of steam held at
 CHAPTER 708.19-400
Maintenance of the circulating Oil
HEAVY INDUSTRIES PAGE 1(1)

As a supplement, and for reference during a) due to the oil temperature being higher
later inspections, we recommend that in than that during flushing,
parallel to using the checkbag, the clean-
liness of the lub. oil is checked by particle b) due to actual engine vibrations, and
counting, in order to find particle concentra- ship movements in heavy seas.
tion, size and type of impurities. When
using particle counting, flushing should not Important: When only a visual inspection
be accepted as being complete until the of the lub. oil is carried out, it is import-
cleanliness is found to be within the range ant to realise that the smallest particle
in I S 0 4406 level 1 19115 (corresponding to size which is detectable by the human
NAS 1638, Class 10). eye is approx. 0.04 mm.
In order to improve the cleanliness, it is During running of the engine, the lub. oil
recommended that the circulating oil centri-. film thickness in the bearings becomes as
fuges are in operation during the flushing low as 0.005 mm. Consequently, visual
procedure. The centrifuge preheaters ought inspection of the oil cannot protect the
to be used to keep the oil heated to the bearings from ingress of harmful particles.
$roper level. it is recommended to inspect the lub. oil in
accordance with ISO 4406.
Note: If the centrifuges are used without
the circulating oil pumps running, then they
3. Circulating Oil Treatment
will only draw relatively clean oil, because,
on account of low oil velocity, the particles
3.1 General
will be able to settle at different places
within the system.
Circulating oil cleaning, during engine ope-
A portable vibrator or hammer should be ration, is carried out by means of an in-line
used on the outside of the lub. oil pipes oil filter, the centrifuges, and possibly by-
pass filter, if installed, as illustrated on
during flushing in order to loosen any impu-
rities in the piping system. The vibrator is to Plate 70818.
be moved one d e t r e at least every 10
minutes in order not to create fatigue fail- The engine as such consumes about 0.1
ures in piping and welds. g/BHPh of circulating lub. oil, which must
be compensated for by adding new lub. oil.
i

A flushing log, see Plate 70822, is to b e

used during flushing and for later reference. It is this continuous and necessary refresh-
ing of the oil that will control the TBN and
As a large amount of foreign particles and viscosity on an acceptable equilibrium level
dirt will normally settle in the bottom tank as a result of the fact that the oil consumed
during and after the flushing (low flow velo- is with elevated figures and the new oil
city), it is recommended that the oil in the supplied has standard data.
bottom tank is pumped to a separate tank
via a 10 pm filter, and then the bottom tank In order to obtain effective separation in the
is again cleaned manually. The oil should centrifuges, it is important that the flow rate
be returned to the tank via the 1Opm filter. and the temperature are adjusted to their
optimum, as described in the following.
If this bottom tank cleaning is not carried
out, blocking up of the filters can frequently 3.2 The Centrifuging Process
occur during the first service be-
r
cause settled particles can be dispersed Efficient oil cleaning relies on the principle
again: that - provided the through-put is adequate
and the treatment is effective - an equili-
brium condition can be reached, where the
 Maintenance of the circulating Oil CHAPTER 708.20-40~
HEAW WWSTRIES PAGE l(1)

i engine contamination rate is balanced by A centrifuge can be operated at greatly

the centrifuge separation rate i.e.: varying flow rates (Q).

Contaminant quantity added to the oil per Practical experience has revealed that the
' hour = contaminant quantity removed by content of pentane insolubles, before and
the centrifuge per hour. after the centrifuge, is related to the flow
rate as shown in Fig. 2.
It is the purpose of the centrifuging process
to ensure that this equilibrium condition is Pentane insolubles %
reached, with the oil insolubles content (difference, beforelafter centrifuge)
being as low as possible.

Since the cleaning efficiency of the centri-

fuge is largely dependent upon'the flow- Fig. 2
rate, it is very important that this is opti-
mised.

The above considerations are further ex-

plained in the following.

3.3 The System Volume, i n Relation t o Fig. 2 illustrates that the amount of pentane
< the Centrifuging Process insolubles removed will decrease with rising
Q.
As mentioned above, a centrifuge working
on a charge of oil will, in principle, after a
It can be seen that:
certain time, remove an amount of contami-
nation material per hour which is equal to
< .
the amount of contamination material pro- a) At low Q, only a small portion of the oil
- ?? is passing the centrifugelhour, but is
; duced by the engine in the same span of
being cleaned effectively.
time.
I

This means that the system (engine, oil and b) At high Q, a large quantity of oil i s
passing the centrifugelhour, but the
centrifuges) is in equilibrium at a certain
cleaning is less effective.
level of oil contamination (Peq) which is
usually measured as pentane insolubles %.
Thus, by correctly adjusting the flow rate,
an optimal equilibrium cleaning level can be
In a small oil system (small volume), the
obtained (Fig. 3).
equilibrium level will be reached sooner
than in a large system (Fig. I ) - but the Pentane insolubles equilibrium level %
final contamination level will be the same
for both systems - because in this respect b
the system oil acts only as a carrier of con- Fig. 3
tamination material.
Pentane insolubles %

Fig. 1

Time
 CHAPTER 708.21 -4OD
Maintenance of the circulating Oil
HEAVY INDUSTRIES PAGE 1(1)

This minimum contamination level is ob- In general,

tained by employing a suitable flow rate
that is only a fraction of the stated maxi- a) the optimum centrifuge flow rate for a
mum capacity of the centrifuge (see the detergent oil is about 20-25% of the
centrifuge manual). maximum centrifuge capacity,

3.4 Guidance Flow Rates b) whereas, for a straight oil, it is about

50-60%.
The ability of the system oil to ''carry" con-
tamination products is expressed by its c) This means that for most system oils of
detergencyldispersancy level. today, which incorporate a certain de-
tergency, the optimum will be at about
This means that a given content of contami- 30-40% of the maximum centrifuge
nation - for instance 1% pentane insolubles. capacity.
- will, in a detergent oil, be present as
$mailer, but more numerous particles than The preheating temperature should be
in a straight oil. about 80 C

Furthermore, the particles in the detergent

oil will be surrounded by additives, which 4. Oil Deterioration
results in a specific gravity very close to
that of the .oil itself, thereby hampering 4.1 General
particle settling in the centrifuge.
Oil seldom loses its ability to lubricate, i.e.
This influences the position of the minimum to form an oil film which reduces friction,
in Fig. 3, as illustrated in Fig. 4. but it can become corrosive.

Pentane insolubles equilibrium level % If this happens, the bearing journals can be
attacked, such that their surfaces become
too rough, and thereby cause wiping of the
Fig. 4
white metal.

Straight mineral oil In such cases, not only must the bearing
metal be renewed, but also the journals
(silvery white from adhering white metal)
will have to be re-polished.

Lubricating oil corrosiveness is either due

to advanced oxidation of the oil itself (Total
As can be seen, the equilibrium level in a Acid Number, TAN) or to the presence of
detergent oil will be higher than in a straight inorganic acids (Strong Acid Number, SAN).
oil, and the optimum flow rate will be lower. See further on in this Section.

However, since the most important factor is In both cases the presence of water will
the particle size (risk of scratching and multiply the effect, especially an influx of
wear of the bearing journals), the above- sea water.
mentioned difference in equilibrium levels is
of relatively minor importance, and the 4.2 Oxidation of Oils
following guidance figures can be used:
At normal service temperature the rate of
oxidation is insignificant, but the following
three factors will accelerate the process:
 CHAPTER 706.22-40D 7
Maintenance of the circulating Oil
HEAW *IDUSTRIES PAGE 1(1)

i a) Hiah Temperature 4.3 Signs of Deterioration

The te'mperature level will generally in-
If oxidation becomes grave, prompt action
crease if the coolers are not effective.
is necessary because the final stages of
deterioration can develop and accelerate
Local high-temperature areas will arke in
very quickly, i.e. within one or two weeks.
pistons, if circulation is not continued for
about 15 minutes after stopping the engine.
Even if this seldom happens, it is prudent to
be acquainted with the following signs of
The same will occur in electrical preheaters,
deterioration, which may occur singly or in
if circulation is not continued for 5 minutes
combinations.
after the heating has been stopped, or if the
heater is only partly filled with oil (insuffi- -
cient venting).
- The sludge precipitation in the centri-
fuge multiplies.
b) Air Admixture - The smell of the oil becomes bad (acrid
Good,venting of the bottom tank should be or pungent).
arranged.
- Machined surfaces'in crankcase be-
The total oil quantity should be such that it come coffee-brown (thin layer of lac-
is not circulated more than about 15-18 quer).
t times per hour. This ensures that sufficient
time exists for deaeration during the period - Paint in crankcase peels off, or blisters.
of "rest" in the bottom tank.
- Excessive carbon deposits (coke) are
It is important that the whole oil content formed in piston cooling chambers.
\ . takes part in the circulation, i.e. stagnant
- 3 .oil should be avoided. In serious cases of oil deterioration, the
system should be cleaned and flushed
c) Catalytic Action i thoroughly, before fresh oil is filled into it.

Oxidation will bk considerably accelerated if 4.4 Water in the Oil

oxidation catalysts are present in the oil.
i
Water contamination of the circulating oil
In this respect, wear particles of copper are should always be avoided.
especially bad, but also ferrous wear par-
ticles and rust are active. The presence of water, especially salt
water, will:
In addition, lacquer and varnish-like oxida-
tion products of the oil itself have an acce- - accelerate oil oxidation (tend to form
lerating effect. Therefore, continuous clean- organic and inorganic acids)
ing is important to keep the "sludge" con- - tend to corrode machined surfaces and
tent low. thereby increase the roughness of
bearing journals and piston rods, etc.
As water will evaporate from the warm oil in (see e.g. 'Crosshead Bearings' in this
the bottom tank, and condense on the tank Chapter).
ceiling, rust is apt to develop here and fall - tend to form tin-oxide on white metal
into the oil, thereby tending to accelerate (see 'Crosshead Bearings').
oxidation. This is the reason for advocating
the measures mention in Chapter 702, point In addition, freshwater contamination can
B5, concerning cleaning and rust preven- enhance the conditions for bacteriological
tion. attack.
 CHAPTER 708.23-40D
Maintenance of the circulating Oil
~ U V Y INDUSTRIES PAGE 1(1)

For alkaline oils, a minor increase in the In addition to the above, oil samples should
freshwater content is not immediately detri- be sent ashore for analysis at least every
mental, as long as the engine is running, three months. The samples should be taken
although it should, as quickly as possible, while the engine is running, and from a test
be reduced again to below 0.2% water cock on a main pipe through which the oil is
content. circulating.

If the engine is stopped with excess water Kits for rapid on-board analyses are avail-
in the oil, then once every hour, it should able from the oil suppliers. However, such
be turned a little more than 112 revolution kits can only be considered as supplemen-
(to stop in different positions), while the oil tary and should not replace laboratory ana-
circulation and centrifuging (at preheating lyses.
temperature) continue to remove the water.
This is particularly important in the case of'
sea water ingress.

Water in the oil may be noted by "dew"

formation o n the sight glasses, or by a
milky appearance of the oil.

Its presence can also be ascertained by

heating a piece of glass, or a soldering iron,
to 200-300'C and immersing it in an oil
sample. if there is a hissing sound, water is
present.

If a large quantity of (sea) water has enter-

ed the oil system, it may be profitable to
suck up sedimented water from the bottom
of the tank. Taste the water for salt.

In extreme cases it may be necessary to

remove the oillwater mixture, and clean
andlor flush the system, before filling up
again with the cleaned oil, or the new oil.

4.5. Check on Oil Condition

As described in the foregoing sub-sections

4.3 and 4.4, the on board surveillance of oil
condition involves keeping a check on:

- alterations in separated sludge amount

- appearance and smell of the oil
- "dew" on sight glasses
- lacquer formation on machined surfaces
- paint peeling and/or blistering
- "hissing" test
- carbon deposits in piston crown.
 \
CHAPTER 708.24-40D
Maintenance of the circulating Oil
HEAW INWSTRlES PAGE 1(1)

5. Circulating Oil: Analyses & Characteristic Properties

Used-oil analysis is most often carried out at oil company laboratories. It is normal sewice
for these to remark upon the oil condition, based upon the analysis results.
The report usually covers the following characteristics:

. Remarks Guiding Limits

for used oils
Oil Type Alkaline detergent (for 2-stroke engines)

Specific Gravity Usually 0.90-0.98. Mainly used for identification of the

oil.
* 5%
(of initial value)

Viscosity The viscosity increases with oil oxidation, and also by max. + 40%
contamination with cylinder oil, heavy fuel, or water. min. - 15%
A decrease in the viscosity may b$ due to dilution with (of initial value)
diesel oil.

Lowest temperaiure at which the oil gives off a com-

bustible vapour. Gives an indication of possible fuel oil min. 1 8 0 t
contamination.

TAN This expresses the total content of organic and inor-

(Total Acid Number) ganic acids in the oil: max. 2
Organic (or weak) acids are due to oxidation.
TAN = SAN +Weak acid number.

SAN This expresses the amount of inorganic (or strong)

(Strong Acid Number: acids in the oil.
These are usually sulphuric acid from the combustion
chamber, or hydrochloric acid arising from sea water
(ought to be stated in the analysis).
SAN makes the oil corrosive (especially if water is pre-
sent) and should be zero.

AlkalinitynBN Gives the alkalinity level in oils containing acid neutra- max. + 100%
(Total Base Number) liking additives. min. - 30%
(of initial values)

Water Risky if TAN and SAN are high. fresh: 0.2%

Sea water has a higher corrosive effect than fresh water (0.5% for short periods)
(see previous point 4.4). Saline: trace

Conradsen Carbon Residue from incomplete combustion, or cracked lubri- max. + 3%

cating and cylinder oil.

Ash Sdme additives leave ash, which may thereby be used

to indicate the amount of additives in the oil. The ash
can also consist of wear particles, sand and rust. max. + 2%
The ash content of a used oil can only be evaluated by
comparison with the ash content of the unused oil.

lnsolubles Usually stated as pentaneheptane and benzene in- Non-coagulated pentam

is checked as follows:
-
soluble~.The amount of ~nsolublelnaredients in the 011 insolubles
max. 2%
Equal parts of the oil sample are diluted with benzene
(C6H6)and normal pentane (C,H,) or heptane (C,H,).
As oxidized oil (lacquer and varnish-like components) is
only soluble in benzene, and not in pentane or heptane. Non-coagulated
the difference in the amount of insolubles is indicative benzene insolubles
of the degree of oil oxidation. max. 1%
The benzene insolubles are the solid contaminants.

The above limiting values are given for reference /guidance purposes only.
 CHAPTER 708.25-40D
Maintenance of the circulating Oil
HEAW INDUSTRIES PAGE l(1)

The assessment of oil condition can seldom This will remove any very fine soot and
be based on the value of a single para- oxidation products not taken out by the
meter, i.e. it is usually important, and ne- centrifuging, and thus make the oil suitable
cessary, to base the evaluation on the over- for returning to the circulating system.
all analysis specification.
Provided that the circulating oil is an alka-
For qualified advice, we recommend con- line detergent type, it is not necessary to
sultation with the oil company or engine analyse each charge of cleaned drain oil
builder. before it is returned to the system. Regular
sampling and analysis of the circulating oil
and drain oil will be sufficient.
6. Cleaning of Drain Oil from
Piston Rod Stuffing Boxes
. If, however, the circulating oil is not alka-
line, all the cleaned drain oil should be
plate 70823 checked for acidity, for instance by means
of an analysis kit, before it is returned to
The oil which is drained off from the piston the system.
rod stuffing boxes is mainly circulating oil
with an admixture of partly-used cylinder oil The "total acid number" (TAN) should not
and, as such, it contains sludge'from the exceed 2. See also item 5, Circulating oil:
scavenge air space. Analyses & Characteristic Properties '
In general, this oil can be re-used if
thoroughly cleaned. If the TAN exceeds 2, the particular charge
of drain oil should be disposed of.
Plate 70823 shows the cleaning installa-
tions.(Option)

The drain oil is collected in tank No. 1.

When the tank is nearly full, the oil is trans-
ferred, via the centrifuge, to tank No. 2, and
thereafter, via the centrifuge, recirculated a
number of times.

When centrifuging the stuffing box drain oil,

the flow-rate should be decreased to about
50% of what is normally used for the circu-
lating oil, and the preheating temperature
raised to about 90C This is because, in
general, the drain oil is a little more viscous
than the circulating oil, and also because
part of the contamination products consist
of oxidized cylinder oil, with a specific grav-
ity which does not differ much from that of
the circulating oil itself.

Water-washing should only be carried out if

recommended by the oil supplier.

Finally, the centrifuged oil, in tank No. 2,

should be filtered a number of times
through the cellulose fine filter, at a tempe-
rature of 60-80 C .
 1. System Details 1.1 Pressure Adjustment

Plate 708248 The oil pressure is adjusted in the following

way:
To prevent the circulating oil in the crank-
case from being contaminated with fuel, the 1. Open the valves in the system and start
engine is provided with a separate forced circulating pump No. 1 .
lubrication system which supplies oil to the
camshaft bearings, roller guides and hy- 2. Check that the oil circulates and that
draulically operated exhaust valves. there is sufficient oil in the tank.

This oil is taken from a special tank by one 3. Set the pump by-pass valve to open at
of the two circulating pumps, and is then
passed through a cooler and a full flow
filter.
. the maximum working pressure of the
pump - not, however, higher than 4
bar. Adjust in steps (while a valve in
7

the pressure piping is slowly closed and

The qbsolute fineness of the full flow filter opened) until the pressure, with closed
should be 50 pm (0.05 mm), corresponding valve, has the above-mentionedvalue.
to a nominal fineness of 30 1411 at a retain-
ing rate of 90%. Make the same adjustment with circu-
lating pump No. 2.
From the bearings and roller guides, the oil
drains to the bottom of the bearing hous- 4. In some cases, the pump capacity can
ings, where a suitable oil level is main- be so large that problems can arise in
tained to lubricate the running surfaces of draining the oil quickly enough out of
the cams. the roller guide housing.

1. The lub. oil is drained back to the tank It may therefore become necessary to
through a magnetic filter. reduce the spring-pressure on the
I pump by-pass valve, so that the surplus
2. The cleanjng of the camshaft oil is capacity flows back to the tank.
done by the by-pass fine filter unit
which is connected to the camshaft lub.
i
oil tank. The lub. oil is drawn from the 2. Camshaft oil
bottom of the tank by a screw pump
and is returned to the tank through a (NB: The camshaft oil also operates the
fine filter. hydraulic exhaust valves).

For check of the by-pass filtration sy- The same oil as in the engine circulating
stem, start the screw pump and check system is normally used.
the pressure drop across the fine filter.
Normal pressure drop is 0.8 bar. When H.D. oils, as used in auxiliary engines, may
1.8 bar is reached, the filter cartridge also be employed.
should be replaced and discarded.
2.1 Fuel Contamination
The system is fitted with pressure-switches,
which are activated at low oil pressure for Regularly check the camshaft lub. oil for
signal to an alarm device and for automatic fuel contamination, and change it if the fuel
start of the stand-by pump. content exceeds 10%. ,
C-
CHAPTER 708.27-40D
HEAW INDUSTRIES PAGE 1(1)

Checking is recommended at intervals of micron filter material should be inserted

max. three months. inside the filter basket.

The dilution will be indicated by: Remove one inspection hole cover on
each camshaft roller guide housing.
- increasing oil level in the tank;.
- smell of the oil; Remove the lub. oil inlet pipe sections
to all camshaft roller guide housings,
- increasing oil viscosity (see diagram, Plate 70825), and in-
(in the case of HFO contamination) spect internal cleanliness of all opened
pipes.
It can also be "measured by a flash-point
test, but this can only be done ashore.

2.2 Water Contamination

. Connect a flexible hose with a valve to
the open end of the lub. oil pipe at
point (B) of each cylinder unit, and
suspend the flexible hose through the
blso regularly check the oil for water conta- open inspection hole into the corre-
mination. - sponding camshaft oil pan.

Water ingress is indicated by: In order to monitor the cleanliness of

the system while the flushing is in pro-
1. Increased level in the oil tank gress, a 50 micron checkbag may be
fitted to the end of the flexible hose in
2. Discolouration of the lub. oil the outmost cylinder unit.

3. Sudden (momentary) increase of pres- Regarding recommended design of the

sure differential across the by-pass checkbag housing, see Plate 70821.
filter.
To improve the cleanliness, it is recom-

- l bv- ass filter cart-

The water will s ~ b ithe
ridge. ~ o p s e ~ u & l the'dater
~, has to be
removed from the oil by means of centrifug-
mended to operate the CJC-filter (fine
filter) or an additional 6-10 pm filter,
see Plate 70825.
ing, before the cartridge is replaced.
i
After flushing, the lub. oil pipe blank
NB: Before the oil is returned to the s y - flanges at points Y & 2,other possible
stem, it should be checked for possible fuel "blind ends" and the camshaft lub. oil
oil content. tank should be opened for inspection
and manual cleaning.
2.3 Flushing Procedure, Separate
Camshaft Lub. Oil System. Flushing log, see Plate 70822, is to be used
during flushing and for later reference.
Plate 70825

In principle, the flushing procedure for the

main lub. oil system is used(see 'Mainten-
ance of the lubricating oil' ,Item 2.2
'Flushing procedure' ),with the fol-lowing
modifications:
r

1. The standard 50 micron filter basket

should be either exchanged with a 6-10
micron filter basket, or additional 6-10
 Camshaft Lubrication for Engines ,,, 70728-40D
with Uni-Lube System PAGE
HEAW INDUSTRIES l(1)

b 1. System Details 3. Flushing Procedure

Plate 70824A
note: Follow these instructions together
The camshaft bearing and the fuel and with the instructions given in 'Maintenance
exhaust roller guides are lubricated by the of the circulating oil', Item 2.2 'Flusging
main lub. oil pumps. procedure' .

The exhaust valve actuators also receive oil I. Remove the inspection hole cover of
from the main lub. oil system each camshaft roller guide section.

Booster pumps are installed in order to in- 2. Remove the oil inlet pipes to all cam-
crease the oil inlet pressure. shaft roller guide sections and exhaust
valve actuators, see Plate 70825.Also
From the bearings, roller guides and ex- blank off to governor drivelstarting air
haust'valve actuators, the oil drains .to the distributor, etc.
bottom of the bearing housings, where a Inspect inrernal cleanlivess of all
suitable oil level is maintained to lubricate opened pipes.
the running surfaces of the cams. From
here, the lub. oil is drained back to the 3. Connect a flexible hose with a valve to
bottom tank. the open end of the lub. oil pipes at
t point (B) of each cylinder unit. See also
2. Pressure Adjustment Plate 70825.

1. Start the main lub. oil pumps and Suspend the flexible hoses through the
booster pump No. 1. open inspection hole into the corre-
sponding camshaft section.
3 . 2. Set the pump by-pass valve to open at
the maximum working pressure of the 4. Keep the booster pumps running during
pump-not, however,: below 3bar. the flushing procedure.

Adjust in steps (while the outlet valve is 5. In order to monitor the cleanliness of
!,
i
slowly closed and opened) until the the system while the flushing is in pro-
pressure, with closed valve, has the gress, a 50 micron checkbag may be
above-mentioned value. fitted to the end of the flexible hose in
the outmost cylinder unit.
Adjust booster pump No. 2, using the
same method. Regarding recommended design of the
checkbag housing, see Plate 70821.
3. Adjust the pressure control valve fitted
at the end of the inlet pipe, so as to 6. After flushing, open the lub. oil blank
obtain the pressure indicated in flanges and any other possible "blind
Capter 710 ends" for inspection and manual clean-
ing.

4. When the engine is running, it may 7. Use the flushing log, Plate 70822,
become necessary to readjust the pres- during flushing and for later reference.
sure control valve, to maintain the re-
quired pressure.
 CHAPTER 706.29-40D
Turbocharger Lubrication
HEAW INDUSTRIES PAGE 1(1)

1. MAN B&W TIC, ~ y s f e mDetails

The lub. oil system for the MAN B&W type

of turbocharger is shown separately on
Plate 70826.

The system is supplied from the main lub.

oil system, via inlet, U.
See also Plate 708 19.

The oil is discharged to the main lub. oil

bottom tank via outlet, AB. .
The discharge line is connected to the
.
tenting pipe, E, which leads tO the deck.
,See also Plate 70818.

In case of failing lub. oil supply from the

main lub. oil system, e.g. due to a power
black-out or defects in the system, the
engine will stop due to shut-down. Lubrica-
tion of the turbocharger bearings is ensured
by a separate tank.

The tank is mounted on top of the turbo-

charger, and is able to supply lub. oil until
the rotor is at a standstill, or until the lub.oil
supply is re-established.
I

2. MET TIC, System Details

The MET turbochargers are also lubricated

via the main lub. oil system. See descrip-
tion of turbocharger lub. oil system in Item
1 MAN B& W T/C, System Details :

2. BBC TIC, System Details

The BBCIABB turbochargers are designed

with an integrated lub. oil system, please
refer to the relevant BBCIABB-instruction
manual.
r
Main Bearing, Thick Shell Design PLATE 70801-~OD
HUVY INDUSTRIES PAGE l(1)

A-A
(Bore kelien

Engine types with thick shell main bearing assemblies:

SIWL 50 MC
SIWL 60 MC
SIWL 70 MC
SIWL 80 MC
W L 90MC
 Main Bearing, Thin Shell Design PLATE 70802-40
HEAW IWWSTRKS PAGE l(1)

A-A
(Bore FMief)

B-B
, .
(Tang. Runout)

Engine types with thick shell main bearing assemblies:

S50MC-C
SGOMC-C
S70MC-C
KBOMC-C
S9OMC-T
K90-98MC-C
 Crosshead Bearing PLATE 70803-~OD
HEAVY INDUSTRIES PAGE l(1)

Extend of oil-wedges in crosshead bearing lower shell

On each side of the axial oil groove

 Crankpin Bearing PLATE 70804-40
7

MEAWWWSTRIES PAGE l(1)

B-B
(Tong. R u n - o u t 1

A-A
( B o r e ReL iefl
 r
PLATE 70805-408
Main Bearing Assemblies
HEAW INDUSTRIES PAGE 1(1)

i Fig.1 Thick Shell

Fig.2 Thin Shell

 PLATE 7080640
Guide Shoes and Strips
HEAW NDIJSTRES PAGE 1(1)

C-C

B-B

A-A
r
Thrust Bearing Assembly PLATE 70807-40
HEAW INDUSTRIES PAGE 1(1)
 PLATE 70808-40B
Camshaft Bearing Assemblies
PAGE 1(1)

1 - Shell Assembly
~ i g . Two

Fig.2 One - Shell Assembly

 Inspection of Bearings PLATE 70809-~OD
HEAVY INDUSTRIES Recording of Observations PAGE 1(1)

i
I References to Volume 2, 'Maintenance' 1
Bearing Type Inspection without Open-up Inspection
Opening-up and Overhaul
1
I

Main bearina 905 905

Crankpin bearing 904 904
Crosshead bearing 904 904
Guide shoes 904
Crosshead guides 904
Thrust bearing 905
Camshaft bearing 996 906

Recording of Observations

use the lnspection Sheet, Plate 70814. For help, refer to example, Plate 70813

A) lnsoection without Openina-Up

State the following information:
Date / Signature I Engine running hours I Type of inspection / Bearing type (Plate 70809,
Table 1 ) / Bearing number I Observation (Plate 70812, Table 3) I Remarks / Clearances.

B) Open-Up lnspection and Overhaul

State the following information:
Date I Signature / Engine running hours I Type of inspection / Bearing type (Plate 70809,
Table 1) I Bearing number / Manufacturer's logo / Damage to (Plate 70809, Table 2) /
Observation (qlate 70812, Table 4) / Site and extent of damage (Plate 70810-70811 ) ' /
Remarks / Clearances / Hydraulic opening pressure I Roughness.

i
The site and extent of the damage is determined by:

1) The approx. centre of the damaged area (see examples I, II and Ill).
The axial location (I) of the centre should be stated in (mm) from the aft end of the
bearing or the journal.
2) The extent of the damage defined by a circle with radius (r); or a rectangle (a, b) or
(a, b, +/- c), (see examples I, II and Ill).
Note: For isolated cracks, illustration Ill is used, with the measurement b omitted.

Main Bearing Overlayer

White Metal
Crosshead Bearing
Guide Shoes
Transitions:
Thrust Bearing Oil Wedge OW
Bore Relief BR
Tang. Run-out TR
Back of Shell BS
 IHWSmEs
Inspection of Bearings PLATE
Location and Size of Damage in Bearing Shells PAGE
7081O - ~ O D -
l(1)

lnsoection of bearinas
(Site of damage and size)
0

Upper shell
Y-Y

Lower shell
X.- X

A
Centre
 Inspection of Bearings PLATE 70811- 4 0 ~
lNWSmlES Location and Damage on Pin/ Journal PAGE 1U)

Crosshead pin
(View from aft)
0

Main and crank bearing journals

(View from aft)

@ Main bearing journal

@ Crank pin bearing journal
 PLATE 70812-40
HEAW MDUSTRIES
Inspection of Bearings PAGE l(1)
Observations

i Table 3 Ins~ection - ..
without Ownina-uo 17.1),
I I
Oil Flow
Checks
OF I
U
.
Svmbol-~ - - - - . .-
Ohsenrations
1 OK, similarity
Uneven
Oil Jets . 0.1 I OK, similarity
(crosshead, Guide strips)- Reduced
Missing
Twisted
White Metal WM OK
Squeezed out
Cracks
Loose

Crosshead Guides ' CG

M

SC
. . Missing
OK
Scratches
CO Corrosion

Oil Pan OP
SW
. Silvery White
OK, clean

Oil Condition OC
WM

DK
. White metal fragment
OK
Dark
VVT Water traces
< --

Table 4 Open-up lnspecti,on and Overhaul (7.:

~ - -

Checks Symbc IS Ref.

White Metal WM OK
W Wiping
HC Hard Contact
0s Oil Starvation
CR Cracks
CRC Crack Cluster
Loose
Missing
Spark Erosion
--
Corrosion
Overlayer OL OK
(Crosshead only) Tearing
Wiping
Transitions: OK
Oil Wedge OW Ragged Ridges
Bore Relief BR Wiping
Tag. Run-out TR Disappeared
IournalIPin J/P OK
Spark Erosion
corrosion
Silvery White
Scratches
Back of Shell BS OK
Fretting
Trapped Hard Palrticles
 Plate 70718A-40D
HEAVY INDUSTRIES Circulating Oil System (Outside Engine) PAGE
l(1)
( Engine with Uni-Lube System)
 7
Circulating Oil System (Outside Engine) PLATE 708188-40D
HUW WWSTRIES PAGE 1(1)
( Engine without Uni-Lube System)
 Svstem oil outlet , Crosshead bearinas .Main bearinas

Lubricatina oil to MAN B&W and MET turbocharaers. (see also Plate 70826)
 Flushing of Main Lub. Oil System PMTE 70820-40
HEAW INDUSTRIES Location of Checkbag and Blank Flanges PAGE l(1)

Location of checkbaa and blank flanas.

.

L E ' sample
" Manometer. maximum
recommenaed pressure
Delore cnec&bag= 1 bar
eff. or in accordance
with Intormalion lrom
the checkbag supplier

Blanking off pipes:

1. Main bearing by-pass blanks
2. Crosshead bearings by-pass blanks
3. Blank-off bearings and spray nozzles at main chain
4. Blank-off thrust bearing
5. Blank-off or by-pass axial vibration damper
6. Blank-off torsional vibration damper
7. Blank-off forward moment compensator chain drive
8. Blank-off or by-pass turbocharger
9. Blank-off hrdraulic chain tightener
10. Blank-off PTO-PTI power gear
 PLATE 70821-40
HEAVY INDUSTRIES
Flushing of Main Lub. Oil System ,,,, l(1)
Dimension of Checkbag and Blank Flanges

Sketch o f Alternative Checkbag

checkbag checkbog manof iL
housing: , (inside enginel: f i l t e r c l o t h
50 um
Approx (mote
dtmenstona -
~LaxtbLahos.\

P l a t e . weLded

Checkbag f r a m s

e n c e . t o b e a p p r o x . 5mm i n
@i i , ,
d i o m a t s r . t o a v o i d dcmaga
I -880
t o t h e ch.eckbog a n d a t o o

The above f ~ 1 t . r components can be d e L ~ v e ~ efrom

d MAN BLW D i e s e l

BLank flanges f o r flushing:

A1 B l a n k c t matn b e a r t n g s .
LO_

8) BLank between t a L s s c a p \ c p ~ p e sand c r o s s h e a d e .

d2

H =-
D
i ,~ ~ ~ m e =t D
e r ,,
9 , I, 1;