Student Text - Mechanical - 38-73 PDF

c c G c c c c c c c c c c c c c Engine Components & Construction c c1 c c Physical Layout c The GM 567,645 and 710 Diesel engines are of a "V" design, and are manufactured in 8, 12, 16 and 20 cyl...

c c G c c c c c c c c c c c c c Engine Components & Construction c c1 c c Physical Layout c The GM 567,645 and 710 Diesel engines are of a "V" design, and are manufactured in 8, 12, 16 and 20 cylinder models. Most engines use a left hand c (or counterclockwise)rotation, as viewed from the rear, or flywheel end. Some marin applications use a right hand (clockwise)rotation engine paired with a left hand rotation c engine so the propellers will spin in opposite directions. Others use a right and left c rotation engine coupled to each side of a common gearbox to turn a single propshaft. G The camshaft gear train and turbocharger or rootes blower are located on the rear of the engine. c The governor, oil pumps, water pumps, and strainer housing are located on the G front, or accessory end of the engine. c An important point is that the engine is mounted backwards in the locomotive, c the rear of the engine faces the front of the locomotive. G The engine is arranged into pairs of cylinders, each pair using a common throw on c the crankshaft. The cylinders are divided into two banks, left and right. If you view the engine from the rear facing towards the governor, or accessory end, the left bank is on c the left side, and the right bank is on the right side. b CJ c - ITS LocomotiveTraining Series Student Text 3-1 I G  3 3 3 On a 16 cylinder engine, for instance, the cylinders are numbered one to eight on the right bank, starting with the front right. On the left bank of the engine the cylinders 3 are numbered nine to sixteen, starting with the front left. This gives us pairs of cylinders such as 1 and 9,8 and 16. 3 Opposing cylinders fire 45 degrees of crankshaft rotation apart due to the 45 3 degree "v"layout of the engine. A 16 cylinder engine has one cylinder firing every 3 22 -1/2 degrees of crankshaft rotation (360/16).Since the timing between each power pulse is equal (22 1/2 degrees), the 16 cylinder engine has a balanced firing order. 3 The firing order for a 16 cylinder example engine is 1,8,9, 16, 3,6, 11, 14,4, 5, 12,13, 2,7,10, 15. 3 d 3 3 Icg 8 22-1/2" 22-1/20 3 9 45" 3 16 67- 1/2" 90" u) 112-1/20 135" 3 157-1/2" 3 180" 202-1/20 3 225" 247-312" 3 270" 292-1/2" u 315" 3 3 37-1n o 1c3 9 On 12 and 20 cylinder engines, the firing order is unbalanced, with an unequal number of degrees of crankshaft rotation between power pulses. T o have a balanced es firing order, a 20 cylinder engine would need a power pulse every 18 degrees, and a 12 1) cylinder every 30 degrees, both of which are not practical due to the 45 degree "V" arrangement.The following charts show the firing order and top dead center for 12 and 3 20 cylinder left hand rotation engines. u, u 3 r3 \ * A Ls a 3-2 Electro-Motive Model 567,645 & 710 Series Diesel Engines LJ L) c c L L c 1 19 0" 9" c 8 36" 11 45" c 5 72" 81" c 18 7 108" c 15 2 117O 144" d. 12 17 153" 7 10 180" c 4 12 189" 3 c 10 3 20 216" 225" c 9 5 165" 6 13 252" 261" L 2 4 288" 11 16 297" c 8 9 324" c 6 14 333" c On the 12 cylinder 710 engine, the firing order has been changed in an effort to c smooth out the torsional vibrations caused by the unbalanced firing order of previous engines. This is made possible by using a different crankshaft and camshafts along with a G specially tuned pendulum trpe torsional damper. ci The following is the firing order / top dead center chart for the 12N left hand rotation engine for comparison to the 12 cylinder chart on the previous page. The 12N c engine is only available in left hand rotation versions. 6. c, c. G ic c c c c t2 c c c r NOTE: Always consult your Engine Maintenance Manual for the correct firing order and timing of your engine. This information may be found in Section 0 of the EMM. IlS Locomotive Training Series -Student Text 3-3 I CJ  3 I - 567 645 - 710 Engine Evolution 1 I MODEL YEARS # CYLS 16CYL H.P. IMPROVEMENTS I Top Deck Cover Exhaust Valve Rocker A n Camshaft injector Rocker A n E x h m v.hn, Bridge OVemPOSd Trip Shoe Exhawt Valve Spring F d Manifold Exhaust Valve Injector control Shafl Cylinder Head Injaater Rack Cylinder Test Valve Piaton ThM WMher Fuel injector PMon Carrier Cylinder Head Crab Bon Piaton Pin Air inlel Porn Cnnkcuo Cyl1nd.r Liner Air Box Blade Connecting Rod Water inlet Jumper Oil Drain M d V M ' Water Inla MMlfold Air Box Handhola Cover Main Lube Oil Manifold Piston Cooling Oil Plpe Fork CoMlectlng Rod \' Piaon Cooling Conwcllng Rod B ~ l u t Oil Manifold Main Beating 'A' Frame oil PMl Handhole Cowr Mdn Bearing Cap oil P M ClWlk0haft 0 11h i Qnug. CnnlohaftCoumennl~ Oil Pan Sump \**A L x " l. 4= y Figure 3.1 Cross Sectional Engine Diagram mWAmR mMLa 645 SERIES DIESEL ENGINE I3-4 ElectroMotive Model 567.645 & 710 Series Diesel Engines c c c G G Components L In this section we will look at the major components of the diesel engine, their c;: function and location. This section is intended to aid in identification of engine components and systems. Repair and inspection is covered in the engine maintenance c manual, maintenance instructions documents and in subsequent training manuals. c c Crankcase c The main structural component of the engine is the crankcase or engine block as c shown in Figure 3.2 below. c c G c c c c c G c c c c1 G CI G c c Figure 3.2 Engine Block c c G c c c ITS Locomotive Training Series -Student Text 3-5 I c  3 ' 3 r \ 450 Figure 3.3 Airbox Section (Left) and Airbox Sections in 45 Degree "V" (Right) The engine block is constructed from four lengths of channel welded together to form the 45 degree air box as illustrated in Figure 3.3. The two air box sections then have a tie plate added at the top and a curved plate added in the "V" to form the main oil gallery. Power pack retainers, base rails and " A frames are added to complete the inner air box assembly as shown in Figure 3.4. 3 ! Power Pack Retainers \ Tie Plate curved Plat 3 3 Figure 3.4 Airbox Sub-assembly (Left) and Completed Airbox Assembly (Right) 3j Figure 3.5 illustrates the application of the remainder of the items such as side cover plates, crab supports, cylinder test valve retainers, etc., to complete the construction of the crankcase or engine block. The completed assembly is then measured to ensure there is enough material for the machining processes. The engine block is then heated to between 1050°F and 1200°F to relieve any stress from welding. After being allowed to cool, the block is peened with steel shot, then sent for machining. The block supports the power assemblies and crankshaft, and serves as a mounting for accessories such as the oil pumps, turbocharger, etc. It is the main structural component of the engine, everything else is attached to it. 3-6 ElectroMotiveModel 567,645 & 710 Series Diesel Engines L) c c LJ ci Top Deck Upper Water Manifold c c c c c c c c c c c c Mainframe Member c Figure 3.5 Completed Crankcase Assembly c This engine is called a dry block design, because the engine coolant circulates c through water jackets built into the individual cylinder liners. c Earlier engines (567UV, 5674 and 567B) used "water decks'' and O-rings on the liners and cylinder heads to contain the engine coolant. c c Discharge Water Manitold I c r Water Manifold c c G G c c niet Water Manifold c c c c Figure 3.6 567 W ,5674 abd 567B Block Cross Section c G - l?S LocomotiveTraining Series Student Text 3-7 I L  d Cylinder bores on opposite banks use the same centre line because they share one throw of the crankshaft. This feature allows for a relatively compact design. Exhaust 3 passages are built in to carry the exhaust gasses from the cylinder heads to the exhaust manifold. 3 The crankcase assembly has handholes to allow inspection and servicing of 3 components in the airbox surrounding the cylinder liners. 3 O n the underside of the crankcase are A-frames which form the main bearing 3 ! supports for the crankshaft. Above the A-frames is a standpipe running the full length of the engine which provides a passage for main bearing lubrication. 3 O n each side of the crankcase are located piston cooling manifolds that deliver oil 3 to the underside of each cylinder assembly. 3 Base rails along each side of the crankcase allow for mounting of the oil pan. 3 CRANKCASE COMPARISON 567 - 645 Comparison Crankcase Construction A-Frame Attachment Weld Sizes 567C and Earlier 114" I 5670 and early 645E 318" 645E, I968 and later 112" d31 l 645E, serial ## starting with 1971 I "D" and later (heavy "A" frame) 31 shown below StVldPlp. 31 31 Figure 3.7 "A"-FrameWeld Locations CRANKCASE'A' FRAME SIDE VIEWS 'cpl PREVIOUS 'A' M E NEW HEAW 'A' W E i (pr&To 71D t h n ) (71D QuuAnd On) , Figure 3.8 "A" Frame Configurations U ' L 3-8 ElectrMotive Model 567,645 & 710 Series Diesel Engines LJ c L....~. G G 645E - 645F Comparison G 645F, 1977, legs extended through base rail and welded on both sides LJ (shown Below) c thicker base rail and top deck plate c E CRANKCASE i ThMTopDr* F CRANKCASE G c c c c c c c c c Figure 3.9 645E and 6453 Crankcase Comparison c c 645F - 710 Comparison +1.12"- = c 710G, A frame attachment (+28.45mm) +1.62"7 I I c same as 645F c Note: Additional improvements c to the "G" case: c 1" larger main bearing bore c and cap G 1.5" taller head retainer 6 forging Improved head retainer to c caseceld c 1/16" thicker side sheets 1.62" taller and 1.12" wider G than "F" G G Figure 3.10 645 - 710 Crankcase Comparison c. c ITS Locomotive Training Series - Student Text 3-9 I c i 3 L) 3 Main Bearings and Crankshaft LJ The next components to be covered are the main 3 bearings and crankshaft. Figure 3.6 shows a typical (3 main bearing application. Iys During final machining 3 of the crankcase, all main bearing caps are installed, and 3 the main bearings are line bored; serial numbers are r3 stamped on both the “A” 3 frames and bearing caps on the right side, including 3 position number. 3 The bearing caps are not interchangeable between 3 positions or engines. u Figure 3.1 1 Main Bearings 3 You can see from this illustration that the main bearing caps are held in place by 4 studs with nuts on the top and bottom. 3 The top nuts (culled D nuts) are shaped to fit into recesses in the top of the “ A 3 frame; this prevents them from turning. The studs have a hole drilled through the top; a retainer clip is inserted through this hole and mates with a slot in the top of the D nut to 3 lock the stud and nut together. A special nut and hardened washer complete the bottom of the assembly. Newer 710 engines, due to a new machining process, use an automotive 3 style main bearing cap retaining system. Threads are cut in the “A”frame and the main bearing caps are held in place with cap screws. 3 3 The bearing itself is in two parts, an upper insert and a lower insert, the bearing is a steel backed bronze bearing with a leadkin (babbitt)overlay called a tri-metal bearing. u, The bearing is prevented from turning in the bore by tangs that fit into recesses in 3 the “Kframe and bearing cap. The bearings can be replaced with the crankshaft in the 3 engine by rotating the engine opposite to normal rotation. The upper and lower inserts are not interchangeable. u, Excessive longitudinal movement of the crankshaft is controlled by thrust collars 3 located on the #3 main bearing of the 8 cylinder engine, #3 on the 12 cylinder, #5 and #6 on the 16 cylinder and #6 and #7 on the 20 cylinder. 3 3 Oil passages are drilled through the “A” frames up into the oil gallery to provide main bearing lubrication. A stand pipe protrudes up into the oil gallery from each of 0) these passages to reduce dirt migration to the main bearings by taking the supply from 1 the middle of the gallery instead of the bottom. 13 13 3-10 Electro-tvlotive Model 567,645& 710 Series Diesel Engines L) L L  Crankshaft The crankshaft as shown in Figure 3.12 is a drop forged carbon steel assembly with induction hardened journals (mainand throws). In the 16 and 20 cylinder engines, the shaft is in two parts, bolted together between the #5 & 6 main bearings on the 16 cylinder and #6 & 7 on the 20 cylinder. Figure 3.12 Crankshafts Crankshafts are dynamically balanced, by using counterweights, which compensate for the rotating mass of the crankpin and lower part of the connecting rod. Oil passages (Figure3.13) are drilled in the shaft to allow oil from the main bearings to lubricate the lower connecting rod bearings. Figure 3.13 Oil Passages ITS LocomotiveTraining Series - Student Text 3-11 I......-.....I.-...... -........... -... ,.-. 3 3 3 The ring gear and coupling disc bolted to the rear L) of the crankshaft provides the coupling for the generator, ring I) gear for engagement of the starting motors and holes for an 3 engine turning bar to manually c3 rotate the crankshaft. Degree and top dead center markings 3 are stamped on the outer rim of the coupling disc for reference 3 during maintenance procedures. 3 3 O n some stationary and marine engine applications 3 where there is no generator, a heavy flywheel is fitted to the 3 rear of the engine. O n gene- Figure 3.14 Ring Gear and Coupling Disc rator applications, the flywheel 3 effect is provided by the weight of the main generator rotor. u 3 Torsional Dampers 3 A torsional damper, 3 (sometimes called harmonic balancer) is applied to the 3 front of the crankshaft, directly behind the accessory Q drive gear, to absorb crankshaft torsional vibrations. 3 Four types of torsional 3 dampers have been applied to EMD engines over the years, 3 the spring pack type, gear w e , viscous damper, and the 3 pendulum type. u The spring pack kb torsional damper is used on all 567 engines and 6 4 5 Figure 3.15 Harmonic Balancer and Accessory Drive Gear 3 blower engines only. There are two versiodj-the 3 pack --’ 3 and the 6 pack. The 6 pack damper is recommended as 3 an upgrade for any engine 3 using a 3 pack damper. 3 4 u 3-12 Electro-MotiveModel 567, 645 & 710 Series Diesel Engines LJ -L 5 c c c c c Spring Housing Oil Passage from Crankshaft c c C c c c c. e c c hF c Spring Packs c Spring Drive Pins c Figure 3.16 Spring Pack Torsional Damper with Front Coupling Removed c c Viscous Dampers have a c hollow sealed housing with a heavy inner ring rotating freely c in a thick silicone fluid to c absorb torsional vibrations. These were applied to 645E3 c turbo engines until 1978 and are no longer recommended for c use as the silicone fluid deteriorates and solidifies after c approximately 7 years. c Symptoms of a failed c viscous damper include broken water pump shafts, and severe c vibration. Replace with gear G -. type damper..... I c Figure 3.17 Viscous Damper c c c c c ITS Locomotive Training Series - Student Text 3-13 I c i  3 3 Spider 13 Front Plate intermediate Rear Plate 3 3 3 3 3 3 Figure 3.18 Gear Type Damper, Exploded View 3 4 The gear type torsional damper is a hydraulic paddle wheel device that absorbs 3 torsional vibrations by forcing engine lubricating oil from passages in the crankshaft through narrow passages in the damper.The front plate, intermediate ring and rear plate 3 are cushioned from the spider which is attached to the crankshaft, by the engine lubricating oil. 3 This damper requires no maintenance other than inspection at normal overhaul 3 time, but should be checked for free movement at intervals specified in the applicable 3 Schedualed Maintenance Program. This is done by removing the front crankcase handhole cover and rotating the damper about 10" in each direction. If the damper 3 cannot be moved it should be removed and disassembled. 3 The pendulum type torsional damper is used on the 12N engine only. It uses 3 centrifugal "throw out" weights attached to a center hub to absorb the crankshaft torsional vibrations. 3 3 3 3 3 cg 3 3 3 Figure 3.18a Gear Type Damper :1 3 b 3-14 ElectroMotive Model 567,645 81710 Series Diesel Engines L, 13/ c c c c c Oil Pan G The engine oil pan (Figure 3.19) encloses the lower part of the crankcase 0 assembly, and serves as both a base for the engine and a storage sump for lubricating oil. G CJ c c, c1 Seal O m G c c c ci c Oil 8ump scawhging oil Suctlon Line c Figure 3.19 Oil Pun (Sump) c Handholes are provided at each cylinder location for inspection and servicing of c, engine components. Tubes in the oil pan correspond with holes in the crankcase base rail, and serve as drains for the air boxes. c The oil pan also provides for checking of the oil level with a bayonet type dipstick, c and piping to drain the sump. The pan is fabricated from steel plating and bolts to the c underside of the crankcase assembly. e ci c TYPES OF OIL PANS Standard Capacity Oil Pan ’ / 1 ~00000000 - I I c c G G apacity Oil Pan - I G Marine Type Oil Pan G b G ITS Locomotive Training Series - Student Text c 3-15 1c  3 3 3 3 Power Packs (Assemblies) 3 Each cylinder of the diesel engine consists of a power pack or 3 power assembly as shown in Figure 3 3.20 which is made up of the following parts: 3 cylinder liner 3 cylinder head 3 piston and rings 3 piston carrier assembly connecting rod assembly d bl Depending on your railroads maintenance practices, the power 3 assembly can be removed from the engine piece by piece, or as a c9 complete unit. 3 3 Figure 3.20 Power Assembly 4. 0 1p Cylinder Liner 3 The cylinder liner as shown in Figure 3 3.21 is a cast iron assembly with brazed on outer sleeves. 3 Pilot Stud The unit comprises the cylinder itself, 3 cylinder water jacket, and intake ports. The intake ports are arranged in a row around WatWJacket 3 the circumference of the liner. 3 This arrangement ensures complete Air Inlet Ports cylinder scavenging. 3 Coolant enters the liner from a water 3 Water Inlet manifold in the airbox, through a water jumper, into a flanged connection on the 3 front lower side of the liner. Inside the water Lomr &d 3 inlet is a deflector that prevents erosion and Groom cold spots on the liner. u, 3 Figure 3.21 Cylinder Liner..3 LJ m 3-16 Electro-Motive Model 567, 645 & 710 Series Diesel Engines L) c c G* G c The coolant circulates through the lower liner,up passages between the ports, and c then through the upper liner. From there, the coolant passes through 12 outlet ports on the top of the liner to the cylinder head. The discharge holes are counter bored to retain G red silicone seals with white teflon heat dams. A copper head seal is used between the liner and cylinder head. Eight stud bolts are arranged around the top of the liner to c retain the cylinder head. A special pilot stud is located at the 5 o'clock position to ensure c proper gasket and head alignment. c The liner serial number is stamped below the water inlet on the side of the liner. There are basically two main types of cylinder liner; cast iron and chrome. These terms c refer the treatment of the cylinder walls. The cylinder may have either chrome plated cylinder walls to be used with cast iron piston rings, or laser hardened cast iron walls c used with chrome rings. The type of liner applied is dependant on the type of service (I, the engine is used for. Chrome liners are generally applied when the locomotive must burn high sulphur fuels because they are particularly resistant to corrosion. c The inner surface of the cylinder can be inspected while installed in the engine by c sighting through the airbox and intake ports with the piston at bottom dead centre. c The liner bore diameter is increased approximatly.010" in the port area to relieve c piston ring tension as the rings pass the ports. c The cylinder liners also have seal grooves containing O-rings in the bottom area. These O-rings seal off the airbox from the crankcase and mate with a lower liner insert in ci the bottom of the airbox.Two types of lower liner seals are used, Viton and Polyacrylic rubber. Viton seals offer improved durability over polyacrylic rubber and are identified ci by two red stripes 1/2" wide. Polyacrilyc rubber seals can be used in the lower groove on G all blower engines and in the top groove on all except EC, F, and FB engines. Viton seals are required in the lower groove on all turbo engines and the top groove on EC, F, c and FB engines. c The lower liner insert is a cast iron, replacable, sacrificial wear surface CI that is press fit and removed from the c engine block using special hydraulic equipment. The lower liner pilot area 6 and O-rings wear away the inside diameter of the lower liner insert as a c result of engine vibration and power assembly movement. Two types of G lower liner inserts are in use, the c phosphate coated insert used on the 567 up to 645EC engines and the CI nickel plated insert used on 645F to 710G engines. The nickel plated insert c offers improved wear resistance. A.060" oversize diameter lower liner insert is 6 available for use where the insert G crankcase bore is out of specification, which allows the weld up and re-boring G Figure 3.22 Lower Liner Bore Insert of the insert bore to be postponed. c c ITS Locomotive Training Series -Student Text 3-17 c,  I.-.A_ _,L. - I _.. ,.......... ' ,.~.-,- I L , -,. Piston and Rings The pistons in EMD engines (Figure 3.23) are a cast iron alloy, one piece symetrical design which may be either phosphate coated or tin plated depending on application. Pistons on 567 and 645 engines are phosphate coated, which is not a lubricant, but absorbs engine oil to provide a barrier of lubrication between the piston and liner. The 710 piston has a ,0007" to.0015" (.02 mm/.04 mm) tin plating applied from below the #4 ring land to the bottom of the piston. This was done because of the 20% higher thrust loads from increased connecting rod angularity. Tin plating also I- reduces liner scuffing and is an aid in the " break in process. Figure 3.23 Piston Cut-Away Tin-plated pistons are also available for all types of 645 engines and are recom- mended as an upgrade for EB and later engines to reduce liner bore scuffing. The undercrown of the piston is cooled by lubricating oil supplied by the piston cooling section of the main lube oil pump to the piston cooling pipes. This oil circulates from the piston cooling pipes through the piston carrier to the fins in the undercrown area to remove combustion heat from the piston crown area. The piston has four compression rings (3 for 567 engines) on the upper portion to seal the cylinder from the crankcase.These rings are either ductile steel for use with chrome plated Ring liners, or chrome plated for use with cast iron finished liners. The top ring for use in cast iron - & Belt finished liners is usually stainless steel with chrome plated face and sides that is pre-stressed by shot peening to improve fatigue strength. The rings may be inspected through the airbox handhole with the piston positioned so the rings are visible in the intake ports. Two different sizes of ring belts (distunce from upper side of top piston ring to the top ofthe piston) have been used. Ring belt location affects timing. Blower type 645 pistons have a 3/4"ring belt width as do 645EB and later "fire ring" pistons. O n 64533 pistons the ring belt width is 1 1/4". 100 Drain H& Surfaces Figure 3.24 Tin Plated Piston 3-18 Electro-Motive Model 567,645 & 710 Series Diesel Engines  1 CJ c --- c - -. ,... -.. -..... CI c Two oil control rings are positioned on the lower portion of the piston skirt to c control liner lubrication and prevent excess oil consumption. c c Piston Carrier PISTON CARRIER Step to hold insert % , Oil Draln Hnla (2 The piston rides on a "trunnion" type G carrier assembly (Figure BearingFace- c 3.25).The carrier is fitted inside the piston, c and a thrust washer on top of the carrier allows G the piston to rotate freely in the cylinder. c c The piston is retained by a large snap Bearing Retainer Figure 3.25 Piston Carrier, Rocking pin c ring fitting into a groove in the lower inside piston skirt. The snap ring is not loaded during normal operation as Ci the piston is driven downward with each power stroke. If an injector is cut out or a cylinder is not firing, the snap ring is loaded as it must pull the piston down. c c c CI CI G c c (i c c c Cf Old Desig c c c Figure 3.26 Piston Cooling Tube Assemblies CI c c ITS LocomotiveTraining Series - Student Text 3-19 I c  31i u'.......-._.. 3 Two different types of piston pin-carrier combinations have been used, the plain bore type and the rocking pin b-pe. The plain bore piston pin is I conventional shaped and uses a & ) / bearing insert retained in the carrier by tangs. Silver plated bearing inserts are used on 567 and 645 turbo applications and bronze lined inserts on 567 and 645 11) blower engines. d The "rocking piston pin" is machined on two offset centers.030" (.76 cm)to produce mechanical separations between the pin and bearing insert alternating between the three bearing surfaces in the course of a power cycle. This creates a pumping action to circulate lubricating oil between the pin and bearing. The rocking pin bearing insert is retained by a bolt, locking clip and bearing retainer. O n engines later than 710G3B, the insert is retained by a larger bolt (5116)torqued to 30 ft. lbs. (41 Nm)with no locking clip. 'Piston Cooling Lubrication and cooling of Pipe the carriertpiston assembly is handled by the piston cooling Figure 3.27 Piston Cooling Oil Flow portion of the lube oil system. h o n g each side of the drankcase is the piston cooling manifold, which has small "peel' I pipes for each cylinder. 3i As the pistontcarrier approaches the bottom of the stroke, oil from this pipe is vt directed through a passage in the carrier to the underside of the piston. This oil cools the piston and lubricates the assembly. 3 3-20 Electro-MotiveModel 567,645 & 710 Series Diesel Engines e c c c, c Connecting Rods c The GM diesel engine uses an interlocking connecting rod design (Figure 3.28) to c; connect the power assemblies to the crankshaft. c The connecting rods consist c of fork rods, blade rods, basket halves, and a set of connecting rod c lower bearings with the piston pins bolted directly to the connecting c rods. c Basket Bolts The connecting rod bearing c is held in place by the basket assembly of the fork rod. Two c Bearing Shell \ , dowels in the fork rod locate the ar upper bearing shell, and one c dowel in the basket locates the c Lower BasW lower bearing shell. c This bearing is a two part, steel backed, lead bronze with a c Bob Basket babbitt overlay similar in construction to the main bearings. c Figure 3.28 Connecting Rod Configuration c The blade rod slides back and forth on the back of the upper connecting rod bearing and is held in place by 6 shoulders on the inside of the fork rod. c On left hand rotation engines the fork rods are installed on the left bank of the engine with the dowel on the basket serrations facing outwards.The blade rods are c installed on the right bank with the long "toe" facing inwards. This articulated design c allows for two cylinders to share a common crank throw centerline, greatly reducing overall engine dimensions. c The fork rod has serial numbers stamped in three places; both basket halves, and c above the dowel on the fork rod itself. The blade rod serial number is stamped on the slipper foot opposite the long toe. Fork rods and baskets are not interchangeable, as they c are line bored as an assembly. G A blue color on the sides and top of the blade rod slipper foot is a result of the c hardening process, not a sign of overheating. No abrasive material should be used on the polished slipper foot surface of the blade rod. c The hinge pin type basket halves and connecting rods on 567,567A, 567B, and c 567BC engines are no longer sold or serviced. The recommended upgrade is to replace c them with the 567C type piston, carrier, pin and connecting rod assembly. cf An upgrade for fork rods manufactured before 1972 is to machine off the saddle "earsll, which eliminates the potential for fatigue cracks in that area. This modification c1 procedure is covered in EMD Pointers 6 - 1 1 - 73. c c, ITS Locomotive Training Series -Student Text 3-21 I CI  3 Cylinder Head The next component to be looked at is the cylinder head (Figure 3.29). The cylinder head is a cast iron component, with passages for coolant and exhaust gases. Four exhaust valves control the flow of gases from the cylinder, through the passages, into the exhaust runner in the crankcase. These valves are run in replaceable nitrided valve guides, and held in place by valve springs and keepers. Three basic types of exhaust valves have been used stellite, inconel, and heavy-head inconel. Stellite valves with double groove locks were originally used on the 567 engine but are no longer available. Inconel valves with single groove locks and part number stamped on the stem originally used on the 645 engine are also no longer available. Heavy-headed inconel valves, which are more durable, became the basic valve in 1979 are are retrofitable to all EMD engines. Different valve types may be mixed within low horsepower engines but not within individual cylinder heads. The bottom of the head; or fireface, forms the top of the cylinder and the mating surface with the top of the liner. The fireface has a machined suface called phonographic finish which aids in sealing the head to liner gasket. "Considerable research and development time has been spent on eliminating the main cylinder head problem, fireface cracking between the injector well and the valve seats from thermal fatigue." Fireface temperatures on the latest cylinder heads, (Diamond 6) have been RockerAnn- bb reduced by the addition of internal cooling surface spines, improvement of water flow, and the reduction of fireface metal thickness. Twelve passages around the outer Injector crab....-a diameter of the fireface allow coolant to flow from the liner to the cylinder head. The coolant flows over the inside of the fireface, around the valve guide bores and injector well, and exits the head by a discharge elbow into the engine block. From there the coolant is collected from all cylinders and flows to the radiators. The top of the head is machined for mounting of the injector, rocker arm assembly, and power assembly hold down crabs. The fuel injector is held in the injector well by a hold down crab, and is clamped against a copper seal in the bottom of the well to prevent combustion/compression leakage from the cylinder. Figure 3.29 Cylinder Head Assembly, Exploded View 3-22 ElectroMotiveModel 567,645 & 710 Series Diesel Engines G c...... c.. c c The cylinder head also has a test valve passage that allows testing of firing pressures/ c temperatures, and the expulsion of moisture from the cylinder prior to engine start up. The head is held in place by the 8 liner studs, hardened washers and lock nuts. c c -7.-r,7-"--- -.-,..