lmbo^qfkd fkpqor`qflk Service, W ärtsilä Finland Oy Engine section 11 Crank mechanism
Engine type
Ref. W FI–S
W20
Käyttöohje
Driftsinstruktion
Date Issue 19.01.2004 01
Document No. 2011Q002GB
Page 1(3)
Assembly procedure for connecting rod big end â
Engine type
This Operating Instruction concerns all WÄRTSILÄ 20 engines.
Background
It is essential to pay attention to the dismantling and assembly procedure procedure of the connecting rod because an incorrect assembly procedure can be a direct reason for a failure at the big end of the connecting rod. Therefore the Instruction Manual has been revised accordingly. See section 11 enclosed.
Revised routines
The following assembly routines have been revised: •
the engine block and the distance sleeves after turning the crankshaft to a crank angle of about 55º from top dead center (TDC) towards the operating side for f or the cylinder concerned. See sections 11.4.3 and 11.4.5. Check clearance between
O per pe rating side side
C h e c k th th e c l e a r a n c e !
C h e c k th th e c l e a r a n c e !
•
Lubricate the back side and the end faces of the t he big end bearing shells to ensure proper bed in of the bearing shells in the bore. See section 11.4.5. Caution: Any use of glue on a bearing shell is prohibited!
Wärt Wärtssil ilä ä Finlan nland d Oy Service, Vaasa
P.O. .O. Box 252 252 (Tar (Tarh haajan jantie tie 2) FIN-65101 Vaasa, Finland
Tele Teleccop. +35 +358 10 709 7355 Telecop. +358 6 356 7339
Tel. Tel. +35 +358 10 709 0000
Wärt Wärtssil ilä ä Fi Finlan nland d Oy Oy Service, Turku
P.O. .O. Bo Box 50 50 (S (Stålar ålarmi min nkat katu 45 45) FIN-20811 Turku, Finland
Teleco lecop p. +3 +358 10 10 70 709 32 3279 Telecop. +358 10 709 3410
Tel. Tel. +35 +358 10 10 709 709 0000
Bus Busine iness ID 0773744-3 Registered Office: Vaasa
Service, Wärtsilä Finland Oy
Operating instruction Issue 01 •
•
Document No. 2011Q002GB
Page 2(3)
Check the bearing shell alignment in the connecting rod before tightening to ensure that the bearing shells are mounted straight in the big end bore. See section 11.4.5.
Check of the exposed connecting rod screw section which is valid only for the connecting rod screw with an end plug. The reference measurement is for guidance only and will reveal the condition of the end plug. See section 11.4.5 and Technical bulletin 2011T004. Caution:
-
An end plug may under no circumstances be used with the 270 mm long connecting rod screw.
-
Check that no plug remains in the threaded holes of the connecting rod before mounting the screws.
Connecting rod screw
Replacement recommendation for the connecting rod screw is at latest every 24000 hours. See Technical Bulletin 2011T004.
Standard routines
Wärtsilä would also like to emphasize a few important routines mentioned under “Dismantling and Reassembling hydraulically tightened screw connection”. See chapter 07.3.3 and 07.3.4 in your Engine Instruction Manual. •
•
Expel (return) possible oil from the hydraulic cylinders always back to the pump before the tools are taken into use at dismantling and reassembling. Be aware of the correct turning direction when loosening or tightening the screw nut. Ø Ø
•
On loosening turn the nut counter-clockwise (CCW) On tightening turn the nut clockwise (CW)
To ensure proper hydraulic tightening, raise the pressure in two steps i.e. pump the pressure to 300 bar and turn the nut in a clockwise direction until it has a contact with the connecting rod cap. Increase the pressure further to stated pressure. Turn the nut until it has a close contact with the face again. This time the nut should move just a limited angle, but approximately the same angle for all nuts of the same kind.
Service, Wärtsilä Finland Oy
Operating instruction Issue 01
Document No. 2011Q002GB
Page 3(3)
50 hrs maintenance
Check the tightening of the connecting rod screws after t he first 50 operating hours on a new engine and after overhaul. See chapter 04.4.
Tool maintenance
The hydraulic tool set should be stored in a suitable place and corrosion protected. The set should be regularly checked and worn or damaged parts replaced. See chapter 07.3.2. Special attention should be paid to the following components. •
Pressure gauge: Regularly calibration checked.
•
Hydraulic couplings and hoses: Condition check
•
Hydraulic pump: Condition check.
•
Hydraulic cylinder o-ring: Wear and condition check.
Note! If the hydraulic cylinder o-ring has been exposed outside the cylinder
the oil has to be removed from the cylinder before the cylinder with the oring can be re-installed. To return the o-ring with the oil in the cylinder will only damage the o-ring. It is prohibited to use a malfunctioning hydraulic tool. Recommendation
Replace the old chapters in the Engine Instruction Manual with the new, implement them in the maintenance schedule and follow the revised assembly and maintenance routines.
Warranty
Unless otherwise expressly set forth, no recommendation contained in this document is to be construed as provided due to a defect in the engine, but merely as an improvement of the engine and/or the maintenance procedures relating thereto. Any actions by the owner/operator as a result of the recommendations are not covered under any warranty provided by Wärtsilä and such actions will thus be at the owners/operators own cost and expense.
Letter distribution
Wärtsilä Service Network and owners/operators of WÄRTSILÄ 20 engines.
Letter validity
Until further notice.
Enclosure
Chapter 11 of the Instruction Manual.
ã
â
2004 Wärtsilä Finland Oy – All rights reserved
No Part of this publication may be reproduced or copied in any form or by any means (electronic, mechanical, graphic, photocopying, recording, taping or other information retrieval systems) without the prior written permission of the copyright holder. Wärtsilä Finland Oy makes no representation, warranty (express or implied) in this publication and assumes no responsibility for the correctness, errors or omissions for information contained herein. Information in this publication is subject to change without notice. NO LIABILITY WHETHER DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL, IS ASSUMED WITH RESPECT TO THE INFORMATION CONTAINED HEREIN. THIS PUBLICATION IS CONFIDENTIAL AND INTENDED FOR INFORMATION PURPOSES ONLY.
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Crank Mechanism
11
11. Crank Mechanism: Crankshaft, Connecting Rod, Piston 11.1
Crankshaft 11.1.1 Description of crankshaft
Data and dimensions Material: Weight:
Forged, alloyed steel 750 kg (4L20) 770 kg (5L20) 790 kg (6L20) 1000 kg (8L20) 1110 kg (9L20)
The crankshaft is forged in one piece and provided with two counter-weights per cylinder. The counter-weights are fastened w ith t w o screws ea ch. 4L20 ha s integra ted count er-w eight s. At t he driving end of the engine, th e cra nksha ft is equipped with a V-ring for sealing of the crankcase. The axial clearance is cont rolled by a combined flywh eel/th rust bear ing. A shrink fitt ed gear wheel for driving of the camshaft is located in the driving end. The ma in bear ings a re described in cha pter 10. At t he free end, t here is a gear for driving of w a ter pumps an d the lubricating oil pump. Usually a vibration damper is also installed (separate instructions for the vibration damper are submit ted, if th e engine is equipped w ith such). The crankshaft can be turned by a manual turning device operat ing th e flywheel. The lubricat ing oil is supplied th rough t he side screw h oles in th e engine block to th e ma in bear ings. The oil flow s furt her from the main bearing through the bores in the crankshaft to the connecting rod big end bea ring a nd up in th e connecting r od a nd piston. Due to a special design of th e bores in th e cra nksha ft, th e flow to t he conn ectin g rod is in term itt ent. The oil is forced t o flow in one direction only.
11.1.2 Balancing of crankshaft Data and dimensions Material: Weight:
Steel plate 21 kg
Note!
WÄRTSILÄ 20
The crankshaft is balanced by means of counterweights on the crank webs, two weights per cylinder. The counter-weights are fast ened to th e web with tw o screws (4L20 ha s integra ted count erweights).
The counterweight shall always be assembled with the guide pin to make sure the right position, see Fig 11-1
11 - 1
11
Crank Mechanism
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Positions of counterweights A
Cyl. No.
1
2
3
4
5
6
SECTION A-A
Guide pin A
Fig 11-1
3211599601
11.1.3 Crankshaft alignment 1 Turn crank of the first cylinder n e a r B D C ( b o t t o m d e a d centre) a nd a tt a ch th e cra nksha ft dial indica tor to the centre ma rks in t he tw o cra nk w ebs. The dista nce betw een t he indica tor a nd t he conn ectin g rod should be a s sma ll as possible.
2 Set indicator at zero. 3 Read deflections when turning crank to the rear side, TDC (top dead centre), opera ting side a nd B DC . Record rea dings in the form “Cra nksha ft a lignment”.
Note!
During the alignment procedure the crankshaft should be turned in the anti-clockwise direction, only. 4 Repeat this procedure with other cylinders. 5 Following limits of misalignment a r e s t a t e d for a n e n g in e having normal running temperature (within 5 minutes after run ning a t 60 %loa d or higher for 6 h or more):
a) on the same crank The difference betw een t w o diamet rically opposed rea dings m ust not exceed 0.04 mm a fter inst a lling or rea ligning. Realignm ent is necessa ry if this limit is exceeded by more th a n 0.02 mm.
b) on two adjacent cranks The difference between two corresponding readings must not exceed 0.04 mm. Realignment is necessary if this limit is exceeded.
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Crank Mechanism
11
c) when the crank pin of cyl. 1 is at TDC (reading C) The r ea din g sh ould be nega t ive, ma x. -0.04 mm (-0.08 mm if flex. coupling). B efore realigning th e engine a nd t he driven ma chinery, a control measurement of the ma in bea rings should be made.
Note!
In an engine having a normal ambient temperature, the corresponding values must be based on experiences from the particular installation. Dial indicator position and reading
A
+ 0 -
E
Operating side
Rear side
B
D
107mm
C As seen from flywheel end
Punched points
Fig 11-2
11.2
2011539601
Flywheel 11.2.1 General description of flywheel
Data and dimension Material : Steel plate Weight: about 350 kg
WÄRTSILÄ 20
The steel flywheel is fitted to the crankshaft with four fitted screws and four normal screws. The correct position of the flyw heel is determined by t hree sma ller screws. A gear rim is fitted t o the flywh eel. A crank angle scale is stamped on flywheel. The scale starts from zero for t he TDC for cylinder 1 a nd is divided in 360 ° crank a ngle. The TDC is ma rked for a ll cylinders. The flywheel position indicator is marked with a scale for rea ding of the engine cra nk a ngles, at a n a ccura cy of one (1) degree cra nk a ngle, on t he gra dua tion of the flywheel.
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Crank Mechanism
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Reading of flywheel indicator
A
E N I G N E G N I T A T O R E C I W K C O L C
340
12
5 4 3 2 1 0 1 2 3 4 5
350
Cyl 1 TDC 0 CYL 1, 6 TDC
VIEW A
Fig 11-3
2011690119
11.2.2 Replacing the gear rim If the gear rim is damaged or worn it can be replaced without removing the flyw heel a s follow s:
1 Open the screws which are holding the gear rim a n d remove th e gea r rim fr om t he flywh eel.
2 Cut the ring in suitable pieces. E n s u r e t h a t t h e f ly w h e e l is not da ma ged during t his opera tion.
3 The spare part gear rim is delivered in two pieces, w hich ea sily ca n be mounted on th e flyw heel. Additiona l screw holes for the ring half ends ar e prema chined a t t he fa ctory.
4 Mount the gear rim halves and tighten the fastening screw s t o sta ted t orque, see section 07.1.
5 Check the base tangent lenght over t he number of teeth spa nned , see F ig 11-4.
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Crank Mechanism
11
Base tangent lenght over the number of teeth spanned 1. Gear rim half
1
W /k = 317 .7 48
- 0. 32 0 - 0. 6 40 / 30
Fig 11-4
11.3
3211549418
Turning device The cra nksha ft can be tur ned by a ma nua l turning device opera ting on the flyw heel. The tur ning device consist s of a gear , wh ich is operated with a ratchet. The rotational direction for turning ca n be reversed by a ltering the ra tch position of the ra tchet.
Note!
11.4
The engine must not be started while the turning gear is engaged.
Connecting rod and piston 11.4.1 General description of connecting rod
Data and dimension Material: Special steel, drop forged Weight: 38 kg Bearing type: Bi-metal bearing
WÄRTSILÄ 20
The conn ect ing r od is of th e drop-forged ty pe w ith H -section sha ft . The big end is of “ st epped split line ” design an d precision serra ted at the mating surfaces. This design offers the maximum crank pin diam eter but st ill ma kes it possible to pull the connectin g rod th rough th e cylinder liner. The big end bearing shells are, for correct assembling, axially guided by lugs. The design of the cran ksha ft ena bles the use of a non-grooved upper bearing shell. The tw o connecting rod screw s a re hydr a ulica lly tight ened. The gudgeon pin bear ing bush is st epped to give a la rger bea ring surface on the more loaded lower side. It is lubricated via bores in t he connecting r od. The gudgeon pin is of t he full floa ting design, secured a xially w ith reta iner rings. The oil flow from th e connecting rod is passed through the gudgeon pin further up to the piston. The gudgeon pin ha s shrink fitted plugs in the ends.
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11.4.2 General description of piston Data and dimension Composite piston Material skirt: Nodular cast iron or forged steel Material crown: Forged steel Screw: 10.9 Weight: 22 kg
Note!
The piston is of composite t ype w ith a forged st eel or a nodula r cast iron skirt and a forged steel crown screwed together. The piston skirt ha s a phospha te/gra phite overla y. The piston crow n is cooled w ith lubrica ting oil by mea ns of the cocktail shaker effect. The lubricating oil is led from the main bearing, through the bores in the crankshaft, to the big end bearing, and further through the bores in the connecting rod, gudgeon pin an d piston skirt , up to the cooling space, from w here it is dra ined back to the oil sump. The pistons a re provided w ith Wä rtsilä pat ented skirt lubrica ting system. The combustion chamber in the top of the piston is deep, preventing t he fuel jets t o touch t he cylinder liner. The compression ring grooves are hardened for better wear resistance.
Always handle the pistons with care. Do not damage or remove the phosphate/graphite overlay. The piston ring set consists of two compression rings and one spring-loa ded oil control ring. I n t his t hree-ring pa ck, every rin g is specially dimensioned and profiled for the task it has to perform. The top ring is provided with a special wear resistant coating. The second compression ring is chrome-plated. The oil cont rol ring is a spring-loa ded, chrome-plat ed oil scra per ring. The side to be upwards of the compression rings is always marked “ TOP ” .
11.4.3 Removing and dismantling of piston and connecting rod Data and dimension Weight: 75 kg
836 003 836 002
1 Remove the cylinder head,see chapter 12 section 12.2.1 Scra pe off ca rbon deposits ca refully from t he slots of th e an tipolishing ring a nd a round th e upper pa rt of the cylinder liner. It is advisable to cover the piston top with cloth or paper pressed tight ly (by a n old piston ring) a ga inst t he cylinder w a ll to collect th e deposits removed.
2 Remove the anti-polishing ring. Use the tool 836002 to extra ct th e ring a nd 836003 to keep th e liner in pla ce during the extracting procedure. By turning the engine, the piston pushes th e a nt i-polishing ring out.
3 Clean the threaded hole in the piston crow n a nd fast en th e liftin g t ool 832002.
4 Turn the crankshaft about 55 ° from TDC tow a rds t he opera t ing sid e for t he cylinder concern ed, see Fig 11-5.
11 - 6
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Crank Mechanism
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5 Lift the distance sleeves 861153 into position on the connecting rod screws and screw on the hydraulic tools 861159 w ith extens ion pieces 861157.
Note!
Check that there is clearance between the distance sleeves and the engine block, before and after applying the pressure on the hydraulic tool. If necessary turn the crankshaft slightly to get the clearance for both sleeves. Dismantling of piston and connecting rod 832 002
Operating side
Check the clearance !
861 153 Distance sleeve 861 157 Extension piece 861 159 Hydraulic cylinder 832 002 Lifting tool for piston
861 153 861 159 861 157 861 159 Check the clearance !
Fig 11-5
2011750240
6 Connect the hoses of the hydraulic pump and proceed DISMANTLING 1. Screw on cylinders by hand 2. Connect hoses, open valve. Tighten cylinders by hand.
to open t he conn ect ing r od nut s, see cha pter 07., section 07.3
7 Remove the hydraulic tool and the distance sleeve from the connecting rod stud s.
8 Open the lower nut and remove the lower stud using t he st ud ext ra cting t ool 803011. The locking screw of the t ool ha s left-ha nd thr eads. Hydraulicoil
3. Screw cylinders 180° counter -clockwise. 4. Close valve, rise pressure. 5. Open the nut about half a turn. 6. Open release valve, remove tool.
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9 Repeat the same procedure as above with the upper nut and stud a nd lift the big end bear ing ca p together wit h th e bea ring sh ell out of th e engine.
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Crank Mechanism
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10 Lift the piston a little to remove the upper big end bearing shell. When lifting t he piston, ta ke ca re not to dam a ge the cra nk pin or t he cylinder liner w a ll.
11 Cover crank pin oil holes with tape. 12 Lift the piston together w ith t he connecting r od out of the engine. When lifting the piston, take care not to damage the cylinder liner wa ll.
13 Remove the retainer ring from the gudgeon pin hole in th e piston, on t he side w here the gudgeon pin dra w ing number is locat ed, by using th e pliers for th e reta iner ring, 843004.
Note!
Never compress the retainer ring more than necessary to remove it from the groove. 14 Drive out the gudgeon pin from t he opposite side. In low temperatures the gudgeon pin may stick but will be easily removed a fter heat ing the piston t o about 30 ° C, e.g. in oil.
15 If the rings and grooves require cleaning, measuring etc., remove the piston rings by using the pliers 843003. Before removing, note the position of the rings to ensure mounting in the same grooves. The design of the pliers prevents overst ressing of the rings. Usin g oth er mean s ma y overstress the rings.
11.4.4 Maintenance of piston, piston rings and connecting rod bearings 1 Clean all the parts carefully. Remove the piston rings, a nd remove burned ca rbon deposits from t he pist on a nd piston ring grooves. Special care should be taken not to damage the piston ma terial.
Never use emery cloth on the piston skirt. The clean ing is fa cilita ted if coked pa rt s a re soaked in kerosene or fuel oil. An efficient car bon solvent — e.g. ARD RO X No. 668 or similar — should prefera bly be used t o fa cilita te clea ning of the piston crown . When using chemica l cleaning a gents, t a ke ca re not to clean piston skirt with such agents because the phosphat e/gra phite overla y ma y be da ma ged.
2 Measure the height of t he piston rin g grooves. 3 Dismantle composite piston for inspection of mat ing surfaces betw een piston skirt a nd piston crown. I nspect a nd clea n oil spaces. See tight ening procedure mentioned in cha pter 07./Piston.
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Crank Mechanism
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When mounting a new cylinder liner, all rings are to be replaced by new ones. After honing of a liner, all rings are to be replaced by new ones. 4 Check the gudgeon bearing bush and big end bearing bore . When mea suring th e big end bea ring bore the connecting rod screws a re to be tightened t o the sta ted pressure. Wear of bimeta l bea ring shells can be sett led by mea suring t he thickness. For this purpose a ball anvil micrometer should be used. The w ear limits given in cha pter 06.2 should be applied. When replacing a big end bea ring both t he upper a nd t he low er bear ing shell should be renewed.
Mark new bearings with the bearing number.
11.4.5 Assembling and mounting of piston and connecting rod 1 Lubricate the gudgeon pin, and mount from the same side from w here it w a s removed, w ith th e end ma rked with t he drawing number in the same direction. The cylinder number is stamped on the piston crown and connecting rod. When changing the piston, mark the new piston with the same cylinder nu mber in t he sa me place as on th e repla ced one. At low t empera tu res, the gudgeon pin ma y stick but w ill be easily fitt ed after hea ting th e piston t o about 30 ° C, e.g. in oil.
2 Mount the retainer ring. Note!
Never compress the retainer ring more than necessary to fit into the groove. If the ring is loose in its groove after mounting, it must be replaced by a new one. 3 Fasten the lifting tool 832002 to the piston crown . 4 Turn the crankshaft about 55 ° from th e TDC towa rds th e opera t ing sid e for t he cylinder concerned, see Fig 11-5.
5 Mount the piston rings by using the pliers 843003. If rings are reused, take care not to turn them upside down. Before new rings are mounted, check the height of the ring grooves. The height must not exceed t he w ear limit. The rings should be placed with gaps located 120 ° in relation to each other. Note the mar k “ TOP ” near t he ring gap.
6 Lift the piston and connecting rod.
WÄRTSILÄ 20
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Crank Mechanism
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7 Lubricate the piston a nd place the clam p device for piston rings, 843002, around the piston, checking that the piston rings slide int o their gr ooves.
8 Spread a thin oil film on the upper big end bearing shell running surface and on its back side. Both end faces to be lubrica ted w ith grea se or oil. Mount the bearing shell with the lug guiding in it s groove into th e connecting rod. Check tha t the shell is mounted st ra ight.
Caution!
Any use of glue on a bearing shell is prohibited. 9 Take off the protecting tape from t he cra nk pin oil holes a nd lubricat e the cra nk pin with clean engine oil.
10
Lower the piston/connecting rod carefully into t he cyl-
inder liner.
11 Lower the piston further unt il the connecting rod ca n be placed on th e cra nk pin.
12 Spread a thin oil film on the lower bearing shell running surface a nd on its ba ck side. B oth end fa ces to be lubrica ted w ith gr ease or oil. Mount t he bea ring shell w ith t he lug guiding in its groove into the bearing cap. Check that the shell is mounted straight.
On a connecting rod screw with an end plug the condition of the plug should be checked before assembly. Connecting rod screws 262 With plug
Plug
270
Without plug
Fig 11-6 Caution!
11 - 10
2011810349
An end plug may under no circumstance be used with the 270mm long connecting rod screw.
WÄRTSILÄ 20
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Crank Mechanism
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Check that no plug remains in the threaded holes of the connecting rod before mounting the screws. 13 Lift the bearing cap in place a nd mount t he upper screw tightening it by hand. Mount the nut. The serrations of the bearing ca p/connecting rod a nd bearing shell ends mus t be in the right relative position to each other. Tighten the nut by hand.
Check of the bearing shell alignment
Incorrect
Fig 11-7
Correct 2011820349
14 Mount the lower screw and tighten both screws with t he t ool 803011 to torq ue, see cha pter 07 sect ion 07.3. Screw on the low er nut a nd tight en it by ha nd.
Caution!
REASSEMBLING 1. Screw on nuts, attach distance sleeve. Screw on cylinders by hand. 2. Connect hoses, open valve. Tighten cylinders by hand.
Hydraulic oil
Overtightenig of the screws will damage the plug at the end of the screws.
15 Lift the distance sleeves 861153 and th e hydr a ulic tools, 861159, t ogether w ith extension pieces 861157, int o posit ion. Check a gain t he alignment of the upper serrat ion a nd bearing shell ends by h a nd before proceeding w ith tight ening of connecting rod nut s. There is no guiding pin for t he upper serr a tion. It is recommended that the pressure is applied in two steps a ccording t o descript ion in cha pter 07., sect ion 07.3.4.
3. Close the valve and pump pressure to the stated value. 4. Screw the nuts until close contact to face. 5. Open the valve and remove tool set.
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Note!
Check before and during the tightening that distance sleeves do not touch the engine block.
Note!
Check that the connecting rod is movable axially after tightening. 16 Check of the exposed section , tha t is va lid only for t he connectin g rod screw s w ith end plug a ccording t o Fig 11-6. The reference measurements are only for guidance to reveal the condition of the end plug. If the length is out of limits, check th e condition of th e plug in t he end of th e connecting rod screw.
Connecting rod screw check +1.1
35.7 -0.9
+1.1
32.7 -0.9
Fig 11-8
2011579446
17 Mount the side covers. 18 Mount the anti-polishing ring. 19 Mount the cylinder head, see cha pter 12 sect ion 12.2.3
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