62 Diesel Technology Copyright Goodheart-Willcox Co., Inc. rocker arms rod cap scavenge efficiency specific gravity stroke sump supercharger swirl chamber systems timing gears top dead center torque torsional harmonics turbocharger two-stroke cycle engine unit injector fuel system valve guide valve overlap valve rotators valve train valve seat volumetric efficiency V-type engine vibration damper water jackets To begin to explain the service and repair of diesel engines, it is necessary to understand the function of each part or system and how all systems work together in a diesel engine. This chapter discusses the major components and assemblies of both two-stroke and four-stroke diesel engines. Major Engine Components It is often easier to think of an engine as a number of subassemblies or part groups rather than as a single assembly of many components. Figure 4-1 illustrates the Figure 4-1. The major subassemblies of a diesel engine. The number and types of components will vary by engine design and manufacturer. (Cummins Engine Co., Inc.) 1 2 3 4 6 5 7 8 9 10 11 12 14 13 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 1. Capscrew 2. Crankshaft pulley 3. Vibration damper 4. Fan idler pulley 5. Pulley, accessory drive 6. Gear cover 7. Gear cover 8. Camshaft gear 9. Capscrew and lockplate 10. Camshaft thrust support 11. Camshaft 12. Idler gear assembly 13. Idler gear assembly 14. Idler gear assembly 15. Crankshaft gear 16. Crankshaft 17. Cap, main bearing 18. Thermostat housing 19. Water pump 20. Thermostat housing 21. Cylinder block 22. Turbocharger 23. Charge air cooler housing 24. Exhaust manifold 25. Lubricating oil cooler 26. Lubricating oil filter assembly 27. Coolant filter 28. Coolant filter head assembly 29. Cylinder liner 30. O-ring, liner 31. Fuel filter 32. Oil pan 33. Piston rings 34. Piston 35. Connecting rod 36. Connecting rod 37. Rocker housing cover 38. Rocker arm assemblies 39. Rocker arm housing 40. Fuel injector 41. Cylinder head 42. Cam follower assembly 43. Flywheel housing 44. Flywheel 45. Air compressor 46. Fuel pump (PT) 47. Fuel pump (transfer)