Instructions for S26MC type engines componets and maintenance edition 2

The two parts which are bolted together.cooling oil is supplied through a The housing is provided with seven crosshead and passed through a bore uppermost of which are fitted with in the

Instructions for Main Engine

All references to this book should include title, edition No., and possibly page No.

Example: Instructions for S26MC Type Engines,

Edition 2, page 901.01-27.

This book is subject to copyright protection The book must not, either wholly or partly, be copied, reproduced, made public or in any other way made available to

a third party without the written consent of this effect from MAN B&W Diesel NS.

MAN B&W Diesel A/S

Stamholmen 161 Teleph.: +45 31 49 25 01DK-2650 Hvldovre Telex : 16592 manbw dk

CYllta:R COVER

Plate 90101

The cylinder cover is made of steel

and has a central bore for the

ex-haust valve, which is attached by

means of four studs. The cover

furthermore has bores for the fuel

valves Other bores have been

provi-ded for starting valve, starting air

inlet, safety valve and indicator

valve.

Cooling water is suppli ed through

cooling water connections from the

cooling jacket around the upper part

of the cylinder liner to an annular

duct at the periphery of the cover.

From this duct the water is passed

through bores on the entire

circum-ference of the cover to another

annular duct which is situated at the

exhaust valve bore, and on through

cooling water connections to the

ex-haust valve proper.

The cylinder cover is tightened

against the top of the cylinder liner

by means of nuts and studs fitted on

the frame box The studs are

tighten-ed by means of hydraulic jacks.

12

REPlJU]JtENT IF

STARn, VALVE Edition 67

Page 1 (1)

1 Shut off the stsrting air and

con-trol air inlet.

Dismount the control sir pipe.

Unscrew the four fixing nuts of

the stsrting valve.

2 Loosen the stsrting valve by

tigh-tening the four nuts on the studs

against the valve housing Remove

the vslve when it comes loose, and

screw the nuts back again.

3 Carefully clean the stsrting valve

bore in the cylinder cover snd, if

necessary, recondition the seat

for the starting valve in the

bore, see 901-3.

After fitting a new O-ring,

lubri-cate an overhauled starting valve

with molybdenum disulphide,

(MoS2)' (for overhauling, see

907-4) Then mount the valve in

the bore of the cylinder cover.

Mount and tighten up the distance

pieces and nuts with the torque

stated in Data.

Mount the control air pipe and

admit starting air and control

air.

Edition 67 EXHAUST VALVE

Page 1 (2) Dismantling

1 Close the cooling water inlet and outlet, and drain the exhaust valve.

Disconnect the cooling water let pipe from the exhaust valve Remove the plate jacket with insu- lation from the intermediate pipe and remove this, see 901-1.1.

out-2 Dismount the high-pressure pipe for the hydraulic valve actuation Dismount the drain oil pipe, the sealing air pipe and the air pipe from the pneumatic exhaust valve Unscrew the four nuts which fasten the exhaust valve.

Attach the crane to the lifting fitting on top of the valve and lift away.

Clean the exhaust valve bore in the cylinder cover carefully and recondition the seating of the bore, if required (see 901-3).

PISTON WITH ROO AND

STlfHNG BOX

rod foot into the crosshead

Plate 90201

PISTON ROO STUFfING BOX

The piston consists of two main

which is designed to prevent theThe piston crown is tightened to the lubricating oil in the crankcase fromupper end of the piston rod by means being drawn up into the scavenge air

of screws The piston skirt is tight- space The stuffing box also preventsened to the piston crown by means of scavenge air (in the scavenge air

crank-case

The piston crown is provided with

chromium-plated grooves for four The stuffing box is mounted with apiston rings All the piston rings flange bolted to the bottom of thehave oblique cuts - two have right- scavenge air space The stuffing boxhand, and two have left-hand cuts At is removed together with the pistonthe top, the piston crown has a rod during piston inspection, but cangroove for the fitting of tools when also be dismantled for inspection in

the piston is to be lifted. the crankcase while the piston

re-mains mounted in the engine

The piston rod has a through-going

bore for the cooling oil pipe, which The stuffing box housing consists of

is secured to the piston rod top The two parts which are bolted together.cooling oil is supplied through a The housing is provided with seven

crosshead and passed through a bore uppermost of which are fitted with

in the foot of the piston rod and on sealing rings to prevent scavenge airthrough the cooling oil pipe in the from passing downwards along thepiston rod to the piston crown piston rod The uppermost of these

sealing rings is a combined sealingThe oil is passed on through a number and scraper ring, provided with an

of bores in the thrust part of the oblique edge, which serves to preventpiston crown and to the space around sludge from the scavenge box fromthe cooling oil pipe in the piston being drawn down to the other sealing

rod From the bore in the piston rod rings

foot the oil is led through the

crosshead to a discharge spout and to The four lowermost ring grooves are

a slotted pipe inside the engine fitted with scraper rings, whichframe as well as through a control scrape the lubricating oil off thedevice for checking the flow. piston rod from the three lowermost

grooves the oil is returned to theThe piston rod foot rests on the crankcase, through bores in the stuf-crosshead, and is guided by a recess fing box housing

in the crosshead Furthermore, the

piston rod foot has an exchangeable Through bores in the housing and ashim to match the different layout of pipe, the uppermost scraper ringthe engine The rod is secured to the groove communicates with a controlcrosshead by means of four screws funnelon the outside of the engine

37

This funnel provides a means ofchecking that the sealing rings andacraper rings are functioning cor-rectly: - blow-by of air indicates adefective sealing ring, while escap-ing oil points to defective scraperrings.

Each of the two sealing rings sists of a four-part base ring whichaccommodates eight sealing segmentsguided by four cylindrical pins Theparts are held in place round thepiston rod by means of a helical

con-spring which is bedded in a machinedgroove on the outside 0f the basering

Each of the four scraper rings is in

three parts and, like the sealing

rings, the scraper rings are held inplace round the piston rod by means

of helical springs

Gaps at the ends of the ring segmentsand slight flattening at the ends ofthe curved contact surface of the

sealing and scraper ring segmentsensures that the rings will bearagains t the piston rod even in worncondition

38

42

MOUNTING OF PISTON 902-2.2

Edi tion 50Page 3 (3)

8 Turn the crosahead into TOC

Re-move the lifting tool for the

piston and the guide ring for the

piston rings

9 Turn the crosshesd downward until

it gives sccess for fitting snd

tightening the four screws in the

piston rod

10 Mount the locking wire in such a

way that both parts are tightened

when the screw ia turned left

11 Turn the crosshead to BDC and

smear the piston rod with

molyb-denum disulphide (MoS2)' Then

turn the crankshaft a couple of

revolutiona

Mount the cylinder cover See

901-1.2

12 Start the engine and keep it

run-ning for approx 15 minutes at a

number of revolutions

correspond-ing to very slow Then stop the

engine and inspect the piston rod

and stuffing box

Edition 50Page 1 (1)

1 Lift the piston high enough togive snple room over the cylindercover studs Mount the clamp onthe piston ',rod so that the dis-tance piece of the clamp lies trueagainst the piston

2 Place the supporting tools on thecylinder cover studs and thenlower the piston until the clamprests on the tools

Remove the li fting tool from thepiston

Hook on the transverse piece tothe crane and attach it to theclamp for tilting the piston

3 Lift the piston to the maximumheight of the crane

Run the crane athwartship and, atthe same time, tilt the piston.Keep the piston rod clear of thecylinder liner and studs whilecarrying out the tilting

4 When the space condit ions allow,straighten up the piston again andlead it over to the cut-out in theplat form for overhauling the pis-ton

When the piston is at a suitableheight over the plat form cut-out,position the piston support aroundthe piston rod and clamp Nowlower the piston while guiding thesupport to the plat form cut-out.After landing the piston and en-suring that it rests correctly onthe support, remove the tiltingtool

Note:

On engines with extremely low liftingheight, use the engine room double-jib crane instead of the transverse

902-2.3 TILTING or PISTONEdition 53

Page 1 (1)

1 lift the piston high enough togive ample room over the cylindercover studs Mount the clamp onthe piston rod so that the dis-tance piece of the clamp lies true

against the piston

2 Place the supporting tools on thecylinder cover studs and thenlower the pis ton until the clamprests on the tools

Remove the li fting tool from thepiston

Hook on the transverse piece tothe crane and attach it to theclamp for tilting the piston

3 Lift the piston to the maximumheight of the crane

Run the crane athwartship and, atthe same time, tilt the piston.Keep the piston rod clear of the

cylinder liner and studs whilecarrying out the tilting

4 When the space conditions allow,straighten up the piston again andlead it over to the cut-out in theplat form for overhauling the pis-ton

When the piston is at a suitableheight over the platform cut-out,position the piston support aroundthe piston rod and clamp Nowlower the piston while guiding thesupport to the plat form cut-out.After landing the piston and en-suring that it rests correctly onthe support, remove the tiltingtool

Edition 59 ROD STurrING BOX

Page 1 (4) OUTSIDE ENGIf£

1 Normally, overhaul of the pistonrod stuffing box is carried out byroutine methods in connection withdismantling (pulling) of thepistons

During overhauls the piston rests

on a support placed over one ofthe cut-outs in the top plat form.The work on the stuffing box isthen carried out on the plat formbelow

Dismantlinq

2 Lift the stuffing box a little upthe piston rod, and mount theworktable round the piston rod at

a suitable working height Landthe stuffing box on the worktable

3 Dismount the collar ring from thestuffing box Remove the O-rings

of the stuffing box If the rings are intact and are to beused again, move them up the pis-ton rod and fasten, for example,

0-by means of tape

Remove the nuts with washers fromthe fitted bolts of the stuffingbox

OVERHAULINGor PISTON 902-S.1

4 Take out the fitted bolts with

spring washers, and pull the

stuf-fing box halves apart and remove

them from the worktable

S Press all sealing rings and

scra-per rings down against the

work-table Measure the clearance

be-tween the ring segments (to judge

whether replacement is necessary,

see Data) After measuring,

dis-mantle and stack the rings in the

same order as when fit ted in the

stuffing box

Clean all the ring segments

care-fully.

Inspect and judge the surface

qua-lity of the sealing rings If the

sliding surfaces have scratches or

marks, replace the rings

6 Carry out check calibration of the

springs (see Data)

7 Inspect the surface of the piston

rod If small longitudinal

scrat-ches have occurred, smooth the

piston rod surface carefully with

a fine grained carborundum stone

In the case of coarse scratches,

it may prove necessary to carry

out machine grinding in a

work-shop

8 Clean the halves of the stuffing

box housing

Edition S9 ROOSTUFFINGIIIXPage 3 (4) REl«JYEDFROMENGII£

Mounting

9 lubricate the piston rod (thearea where' all the ring lS1its inthe stuffing box will be placed)

with molybdenum disulphide(MoS2)•

Assemble all ring lS1its for thestuffing box round the piston rod

on the worktable in the followingway:

Place the segments for the most scraper ring on the work-table, place the spring round thesegments and, by means of the twohooks, assemble the spring ends.Repeat this procedure for theremaining scraper rings

lower-10 On top of the scraper rings,

assemble the two sealing ringunits (each consisting of a4-part and an 8-part ring).Assemble the 8-part sealing ring

so that the two guide pins faceupwards, place the spring roundthe segments and, by means of thetwo hooks, assemble the springends Assemble the 4-part sealingring above the 8-part sealing

ring Push the two rings together

in such a manner that the guidepins in the lower sealing ringengage with the two holes in theupper sealing ring

Finally, assemble the uppermostring unit (consisting of a 4-partscraper ring and an a-part seal-ing ring)

11 Use the stuffing box half on theworktable to adjust the height ofall the assembled ring units onthe piston rod in such a mannerthat the ring units are oppositethe corresponding grooves of thestuffing box housing Subse-quently, push the stuffing boxhalf into contact with the piston

OVERHAUl or PISTON 902-5.1

ROD STUffiNG IIJX Edition 59

REMOVED fROM ENGINE Page 4 (4)

12 Check the ring clearance.

Then place the other half of the

atuffing box housing on the

work-table, pushing it into place

round the rings.

Mount and tighten up the bolts.

Mount the O-rings in the groove

of the stuffing box.

13 Mount the collar ring on the

stuffing box Ensure that the

guide pin of the collar ring fits

correctly in the stuffing box

housing.

14 lift the stuffing box a little.

Remove the worktable and lower

the stuffing box until the 'ears'

rest against the piston rod foot.

902-5.2 OVERHAUl or PISTON Edition 59 ROD STUffING BOX Page 1 0) INSIDE THE ENGlf£

If, in the period between piston overhauls, it becomes necessary to inspect the piston rod stuffing box, this can be done according to the following procedure:

1 Turn the crosshead to about 900

from TDC Mount the rubber hose around the piston rod for protect- ing the crosshesd bearing Mount the collsr ring for the stuffing box on the piston rod.

2 Release the stuffing box through the scavenge space by removing the screws from the collar ring of the stuffing box in the bottom of the cylinder frame box.

3 Mount the collar ring around the piston rod above the stuffing box Turn the crosshead to BDC, thereby withdrawing the stuffing box from the crankcase topplate.

ROO STUffIM; IIJX Edition S9

INSIDE 1H[ EHGIt£ Page 2 0)

4 Lift the stuffing box a little up

the piston rod and mount the

work-table round the piston rod at a

suitable working height Land the

stuffing box on the worktable.

For overhauling the stuffing box,

see procedure 902-S.1.

S Lift the stuffing box a little and

remove the worktable.

Mount the collar ring around the

piston rod below the stuffing box.

Turn the crosshead upwards until

the stuffing box is in place in

the crankcase topplate.

6 Mounting the collar ring around

the stuffing box takes place

through the scavenge space Ensure

that the guide pin of the collar

ring fits correctly in the

stuf-fing box housing.

fdition S9 ROO STUffING BOX

Page 3 0) INSIDE THE ENGIt£

7 When mounting the screws which tighten the collsr ring to the bottom of the cylinder frsme, make sure thst the screw holes in the cylinder frame snd the holes in the collar ring coincide The cir- cular half of the collar ring should face the camshaft side Tighten the screws, see Oata D and secure with the locking plstes.

B Remove the collar ring, below the stuffing box, from the piston rod Remove the protecting rubber hose from the piston rod and crosshead Smear the piston rod with molyb- denum disulphide Then turn the crankshaft a couple of revolu- tions Start up the engine and keep it running for approx 1S minutes at a number of revolutions corresponding to "Dead Slow" After this, stop the engine and inspect the piston rod and stuf- fing box.

902-5.1 OVERHAlLIF PISTON

Edit ion 64 ROOSTLI'FlN; BOX

Page 3 (4) ,REMOVEDFROMEN;II£

.- - Mounting

"-9 Lubricate the piston rod (the

area where' all the ring units in

the stuffing box will be placed)

with molybdenum disulphide

(MoS2)•

Assemble all ring units for the

stuffing box round the piston rod

on the worktable in the following

way:

Place the segments for the

lower-most scraper ring on the

work-table, place the spring round the

segments and, by means of the two

hooks, assemble the spring ends

Repeat this procedure for the

remaining scraper rings

10 On top of the scraper rings,

assemble the two sealing ring

units (each consisting of a

4-part and an a-part ring)

Assemble the a-part sealing ring

so that the two guide pins face

upwards, place the spring round

the segments and, by means of the

two hooks, assemble the spring

ends Assemble the 4-part sealing

ring above the a-part sealing

ring Push the two rings together

in such a manner that the guide

pins in the lower sealing ring

engage with the two holes in the

upper sealing ring

Finally, assemble the uppermost

ring unit (consisting of a 4-part

scraper ring and an a-part

seal-ing rseal-ing)

11 Use the stuffing box half on the

worktable to adjust the height of

all the assembled ring units on

the piston rod in such a manner

that the ring units are opposite

the corresponding grooves of the

stuffing box housing

Subse-quently, push the stuffing box

half into contact with the piston

ROOSTLI'FIN; BOX Edition 64RO«IVEDFROMENGII£ Page 4 (4)

12 Check the ring clearance

Then place the other half of theatuffing box housing on the work-table, pushing it into placeround the rings

Mount and tighten up the bolts.Mount the O-rings in the groove

of the stuffing box

13 Lift the stuffing box a little.Remove the worktable and lowerthe stuffing box until it restsagainst the piston rod foot