LEVEL F PPiissttoonn EEnnggiinnee FFuunnddaammeennttaallss TTCC001100--0055--0011SS Mazda Motor Corporation Technical Service Training Piston Engine Fundamentals CONTENTS TC010-05-01S 1 – INTRODUCTION ............................................................................1 Course Overview ..................................................................................1 Audience and Purpose...................................................................1 Course Content and Objectives .................................................2 How to Use This Guide .........................................................................3 Section Objectives .........................................................................3 Text and Illustrations......................................................................3 Review Exercises ..........................................................................4 2 – BASIC OPERATION.......................................................................5 Objectives .............................................................................................5 How Power is Developed......................................................................6 Harnessing Power..........................................................................6 Controlling Combustion..................................................................7 The Four-Stroke Cycle..........................................................................9 Intake Stroke................................................................................ 10 Compression Stroke .................................................................... 11 Power Stroke ............................................................................... 11 Exhaust Stroke ............................................................................ 11 Summary ..................................................................................... 12 Review Exercise 1 .............................................................................. 12 Basic Design Characteristics .............................................................. 13 Cylinder Configuration ................................................................. 14 Valve Train Type.......................................................................... 15 Bore, Stroke, and Displacement .................................................. 17 Compression Ratio ...................................................................... 18 Engine Components and Systems...................................................... 19 Review Exercise 2 .............................................................................. 19 page i Piston Engine Fundamentals CONTENTS TC010-05-01S 3 – SHORT BLOCK............................................................................ 21 Objectives ........................................................................................... 21 Overview............................................................................................. 22 Cylinder Block ..................................................................................... 23 Construction................................................................................. 24 Crankcase.................................................................................... 24 Crankshaft Main Supports and Bearings ..................................... 24 Crankshaft........................................................................................... 25 Features....................................................................................... 26 Construction................................................................................. 27 Number of Journals...................................................................... 28 Vibration Damper......................................................................... 28 Main Bearings ..................................................................................... 29 Lubrication ................................................................................... 30 Clearance .................................................................................... 31 Thrust Bearings ........................................................................... 32 Review Exercise 3 .............................................................................. 32 Connecting Rods ................................................................................ 34 Construction................................................................................. 35 Cylinder Wall Lubrication ............................................................. 35 Pistons ................................................................................................ 36 Construction................................................................................. Clearance .................................................................................... 37 Piston Rings........................................................................................ 39 Compression Rings...................................................................... 40 Oil Rings ...................................................................................... 41 Review Exercise 4 .............................................................................. 42 4 – VALVE TRAIN .............................................................................. 43 Objectives ........................................................................................... 43 Cylinder Head ..................................................................................... 44 Construction................................................................................. 44 Sealing......................................................................................... 45 Valves ................................................................................................. 46 Components ................................................................................ 46 Construction................................................................................. 47 Multi-Valve Design....................................................................... 47 Valve Seats......................................................................................... 48 Valve Guides....................................................................................... 49 page ii Piston Engine Fundamentals CONTENTS TC010-05-01S Valve Springs...................................................................................... 50 Construction................................................................................. 51 Spring Tension............................................................................. 51 Working Height ............................................................................ 51 Overhead Valve Train ......................................................................... 52 Overhead Cam Valve Train................................................................. 53 Overhead Cam (OHC or SOHC).................................................. 53 Dual Overhead Cam (DOHC) ...................................................... 55 Camshaft Drives ................................................................................. 55 OHV Drive.................................................................................... 56 Chain Adjuster ............................................................................. 57 OHC Drive ................................................................................... 58 Timing Belt Auto Tensioner.......................................................... 59 Belt and Chain Drive.................................................................... 60 Gear-Driven Camshaft with Friction Gear.................................... 61 Camshaft Design ................................................................................ 62 Auxiliary Drives ............................................................................ 63 Lubrication ................................................................................... 63 Camshaft Measurements............................................................. 63 Review Exercise 5 .............................................................................. 64 Valve Adjustment ................................................................................ 65 Valve Clearance .......................................................................... 65 Hydraulic Lash Adjusters (HLA) .......................................................... 66 Description and Operation ........................................................... 66 Bucket-Type HLA......................................................................... 67 Rocker Arm-Mounted HLA........................................................... 68 Regular Oil Changes.................................................................... 68 Pushrods (OHV).................................................................................. 69 Rocker Arms ....................................................................................... 69 Review Exercise 6 .............................................................................. 70 5 – LUBRICATION SYSTEM.............................................................. 71 Objectives ........................................................................................... 71