Engine Repair Engine Repair Student Book COURSE CODE: 32S05T1 ORDER NUMBER: FCS-14567-REF Updated January, 2006 Ford Customer Service Division Technical Training IMPORTANT SAFETY NOTICE Appropriate service methods and proper repair procedures are essential for the safe, reliable operation of all motor vehicles, as well as the personal safety of the individual doing the work This manual provides general directions for accomplishing service and repair work with tested, effective techniques Following them will help assure reliability There are numerous variations in procedures, techniques, tools and parts for servicing vehicles, as well as in the skill of the individual doing the work This manual cannot possibly anticipate all such variations and provide advice or cautions as to each Accordingly, anyone who departs from instructions provided in this manual must first establish that he compromises neither his personal safety nor the vehicle integrity by his choice of methods, tools or parts As you read through the procedures, you will come across NOTES, CAUTIONS, and WARNINGS Each one is there for a specific purpose NOTES give you added information that will help you to complete a particular procedure CAUTIONS are given to prevent you from making an error that could damage the vehicle WARNINGS remind you to be especially careful in those areas where carelessness can cause personal injury The following list contains some general WARNINGS that you should follow when you work on a vehicle • • Always wear safety glasses for eye protection • • • To prevent serious burns, avoid contact with hot metal parts such as the radiator, exhaust manifold, tail pipe, catalytic converter and muffler Be sure that the ignition switch is always in the OFF position, unless otherwise required by the procedure • • Do not smoke while working on the vehicle Set the parking brake when working on the vehicle If you have an automatic transmission, set it in PARK unless instructed otherwise for a specific service operation If you have a manual transmission it should be in REVERSE (engine OFF) or NEUTRAL (engine ON) unless instructed otherwise for a specific service operation • Keep hands and other objects clear of the radiator fan blades Electric cooling fans can start to operate at any time by an increase in underhood temperatures, even though the ignition is in the OFF position Therefore, care should be taken to ensure that the electric cooling fan is completely disconnected when working under the hood Use safety stands whenever a procedure requires you to be under the vehicle • Operate the engine only in a well-ventilated area to avoid the danger of carbon monoxide • Keep yourself and your clothing away from moving parts when the engine is running, especially the fan and belts To avoid injury, always remove rings, watches, loose hanging jewelry, and loose clothing before beginning to work on a vehicle Tie long hair securely behind your head The recommendations and suggestions contained in this manual are made to assist the dealer in improving his dealership parts and/or service department operations These recommendations and suggestions not supersede or override the provisions of the Warranty and Policy Manual, and in any cases where there may be a conflict, the provisions of the Warranty and Policy Manual shall govern The descriptions, testing procedures, and specifications in this handbook were in effect at the time the handbook was approved for printing Ford Motor Company reserves the right to discontinue models at any time, or change specifications, design, or testing procedures without notice and without incurring obligation Any reference to brand names in this manual is intended merely as an example of the types of tools, lubricants, materials, etc recommended for use Equivalents, if available, may be used The right is reserved to make changes at any time without notice WARNING: MANY BRAKE LININGS CONTAIN ASBESTOS FIBERS WHEN WORKING ON BRAKE COMPONENTS, AVOID BREATHING THE DUST BREATHING THE ASBESTOS DUST CAN CAUSE ASBESTOSIS AND CANCER Breathing asbestos dust is harmful to your health Dust and dirt present on car wheel brake and clutch assemblies may contain asbestos fibers that are hazardous to your health when made airborne by cleaning with compressed air or by dry brushing Wheel brake assemblies and clutch facings should be cleaned using a vacuum cleaner recommended for use with asbestos fibers Dust and dirt should be disposed of in a manner that prevents dust exposure, such as sealed bags The bag must be labeled per OSHA instructions and the trash hauler notified as to the contents of the bag If a vacuum bag suitable for asbestos is not available, cleaning should be done wet If dust generation is still possible, technicians should wear government approved toxic dust purifying respirators OSHA requires areas where asbestos dust generation is possible to be isolated and posted with warning signs Only technicians concerned with performing brake or clutch service should be present in the area Copyright © 2002 Ford Motor Company Produced and Coordinated by Technical Support Operations Ford Customer Service Division September, 2002 CUSTOMER EXPECTATIONS Customer Expectations: Service Make it convenient to have my vehicle serviced at your dealership The Service Advisor should Provide me with a clear and thorough explanation of the service performed Call me within a reasonable amount of demonstrate a genuine concern for my service needs time after my service visit to ensure that I'm completely satisfied Fix it right the first time Complete servicing my vehicle in a Be responsive to questions or concerns I bring to your attention timely and professional manner Expectation “Fix It Right The First Time, on Time.” Both service advisors and technicians are important players when it comes to Expectation #3 Why Customers tell us “Fixing It Right The First Time, on Time” is one of the reasons they would decide to return to a dealer to buy a vehicle and get their vehicles serviced Technician Training It is our goal to help the technician acquire all of the skills and knowledge necessary to “Fix It Right The First Time, on Time.” We refer to this as “competency.” Technician’s Role Acquire the skills and knowledge for competency in your specialty via: STST New Model – Self Study – Self Study – FordStar Broadcasts – FordStar Broadcasts – Ford Multimedia Training (FMT) – Instructor Led – Instructor Led The Benefits The successful implementation of expectations means: – Satisfied customers – Repeat vehicle sales – Repeat service sales – Recognition that Ford and Lincoln/Mercury technicians are “the Best in the Business” TABLE OF CONTENTS DAY ONE INTRODUCTION INTRO-1 Engine Repair Curriculum Path Intro-2 Curriculum Prerequisites Intro-2 Curriculum Goals Intro-3 Engine Repair Curriculum Intro-4 Course Objectives Intro-5 Day One Agenda – Morning Intro-6 Day One Agenda – Afternoon Intro-6 Day Two Agenda – Morning Intro-7 Day Two Agenda – Afternoon Intro-7 Day Three Agenda – Morning Intro-8 Day Three Agenda – Afternoon Intro-8 Day Four Agenda – Morning Intro-9 Day Four Agenda – Afternoon Intro-9 PREREQUISITE KNOWLEDGE REVIEW DAY ONE-1 Student’s Answer Sheet Day One-2 DAY ONE INTRODUCTION TO WORKSTATIONS DAY ONE-19 Introduction Day One-20 WORKSTATION DAY ONE-23 Student’s Answer Sheet Day One-29 WORKSTATION DAY ONE-41 Workstation – Run Stand B Student’s Answer Sheet Day One-47 WORKSTATION DAY ONE-63 Workstation – On-Vehicle Student’s Answer Sheet Day One-69 WORKSTATION DAY ONE-79 Workstation – Bench Student’s Answer Sheet Day One-85 DAY TWO Day Two Agenda – Morning Day Two-2 Day Two Agenda – Afternoon Day Two-2 INTRODUCTION TO DAY TWO WORKSTATIONS DAY TWO-9 Workstation Introduction Day Two-10 WORKSTATION DAY TWO-13 Workstation – Engine On Stand Student’s Answer Sheet Day Two-21 Engine Repair September, 2002 i TABLE OF CONTENTS WORKSTATION 6A DAY TWO-31 Workstation 6A – Cylinder Head Disassembly and Measurement Student’s Answer Sheet Day Two-37 WORKSTATION 6B DAY TWO-51 Workstation 6B – Engine Block Disassembly and Measurement Student’s Answer Sheet Day Two-57 WORKSTATION DAY TWO-65 Workstation – Cylinder Heads to Block Student’s Answer Sheet Day Two-73 DAY THREE Day Three Agenda – Morning Day Three-2 Day Three Agenda – Afternoon Day Three-2 Introduction Day Three-4 WORKSTATION AND DAY THREE-11 Workstation – Timing Chain Installation Student’s Information Sheet Day Three-19 DAY FOUR Day Four Agenda – Morning Day Four-2 Day Four Agenda – Afternoon Day Four-2 Introduction Day Four-4 WORKSTATION AND DAY FOUR-11 Student’s Information Sheet Day Three-19 GLOSSARY GLOSSARY-1 ii September, 2002 Engine Repair INTRODUCTION DAY ONE Engine Repair September, 2002 Intro-1 INTRODUCTION ENGINE REPAIR CURRICULUM PATH ENGINE REPAIR CURRICULUM PATH Automotive Measuring Tools T – FMT Prerequisites q Leg gend = Self Study d (SS) – NVH – – = Ford r Multimedia Training r (FMT) – oom – = FORDSTAR T – = Instructor Led – Classroom r – – Electronic System Diagnosis (Classroom) - Intro-2 September, 2002 34S19T0 Engine Repair INTRODUCTION Curriculum Goals The goals of this curriculum are: – To provide the necessary training to enhance the technician’s ability to identify, diagnose, and perform timely “Fix It Right The First Time-On Time” repairs – Increased customer satisfaction – Increased technician productivity – Reduce or eliminate repeat repairs Curriculum Prerequisites All students must have completed the prerequisite courses prior to enrolling in this course Students who not show passing credit in their STARS planner for the previous courses should not be admitted to this class Their presence will slow down the course flow, as well as monopolize valuable instructor time Each technician enrolled in this course must meet the following prerequisites: – NVH – Classroom course code: 30S03T0 – Basic Electrical Theory & Operation – Web course code: 34S11W0 – Electrical Diagnostic Tools and Testing – FMT course code: 34S13M0 – Basic Electrical Diagnosis – Classroom course code: 34S14T0 – Electronics Theory and Operation – Web course code: 34S15W0 – Understanding Electronic Systems – FMT course code: 34S16M0 – Electronic System Diagnosis – Classroom course code: 34S19T0 Engine Repair September, 2002 Intro-3 INTRODUCTION ENGINE REPAIR CURRICULUM The Engine Repair Curriculum Path consists of four types of courses Each course is one of the following types: – Self-Study – This type of course is a self-paced program The technician is responsible for learning the material on his or her own The training material consists of a reference book and an accompanying videotape The videotape is designed to support the material in the reference book and should not be used on its own – Ford Multimedia Training (FMT) – This type of course is also self-paced The multimedia course allows the technician to interact with the training materials The multimedia course allows the technician to utilize the knowledge attained in the self-study course The FMT concentrates on relationships, such as the causeand-effect relationships between symptoms and components – FORDSTAR – This type of course is instructor led, distance learning The technicians interact with the instructor through an interactive satellite communications system – Classroom – The classroom course allows for practical, real-world application of skills and knowledge learned in the other courses The courses included in the Engine Repair Curriculum are as follows: – Engine Repair Fundamentals – Self-Study course code: 32S01S0 – Automotive Measuring Tools – FMT course code: 32S02M0 – Basic Engine Operation and Diagnosis – FMT course code: 32S03M0 – Engine Repair – Classroom course code: 32S05T1 – Servicing Overhead Cam Engines – FORDSTAR course code: 32S06F0 Intro-4 September, 2002 Engine Repair DAY THREE WORKSTATION TIMING CHAIN INSTALLATION STUDENT INFORMATION SHEET TECHNICIAN’S NAME: DIRECTIONS: Follow the workshop manual procedures for timing chain installation Be sure to use all special tools and procedures Modular engine: Perform timing chain installation (be sure crankshaft keyway is set to 12:00 position) – Install front cover – Install oil pickup tube and oil pan – Install valve covers – Install intake manifold Day Three-4 September, 2002 Engine Repair DAY THREE WORKSTATION TIMING CHAIN INSTALLATION STUDENT INFORMATION SHEET TECHNICIAN’S NAME: DIRECTIONS: Follow the workshop manual procedures for timing chain installation Be sure to use all special tools and procedures 4.0L SOHC engine: Perform cam timing procedures – Install front engine cover – Install ladder frame – Install roller finger followers – Install crankcase vent/separator – Install valve covers – Install the lower intake manifold Engine Repair September, 2002 Day Three-5 DAY THREE NOTES Day Three-6 September, 2002 Engine Repair DAY FOUR DAY FOUR Engine Repair September, 2002 Day Four-1 DAY FOUR DAY FOUR AGENDA – MORNING ACTIVITY TIME Engine Replacement Procedure Lecture 8:30am to 10:00am (90 min) BREAK 10:00am to 10:15am (15 min) Complete Day Three workstations 10:15am to 10:40am (25 min) Review Day Three Workstations 10:40 am to 11:00am DAY FOUR AGENDA – AFTERNOON ACTIVITY TIME LUNCH 11:45am to 12:45pm (60 min) Introduce and begin Final Exam 12:45pm to 4:00pm (195 min) Day Four ends Day Four-2 4:00pm September, 2002 Engine Repair GLOSSARY GLOSSARY Engine Repair September, 2002 Glossary-1 GLOSSARY After Top Dead Center (ATDC) – The location of the piston after it has reached the top of its stroke Piston location is measured in degrees of crankshaft rotation Anodizing – An oxidation process in which the work piece surfaces are converted to a hard and porous oxide layer that provides wear and corrosion resistance Anodizing is also used as a decorative finish Babbitt – A low-friction metal alloy It is up to 90 percent tin, to which copper, antimony, lead, zinc, and sometimes other metals are added in small amounts A soft material with a low (600° F) melting point, Babbitt is widely used to coat friction bearings of harder metals Backpressure – A resistance to the free flow of gases or liquid For example, a plugged catalytic converter causes backpressure in the exhaust system which exerts a force back to the engine Excess backpressure makes an engine work too hard to purge itself, reducing engine power Balance Shaft – A shaft located in the cylinder head or block of some engines The balance shaft is driven by the timing chain or belt, and is used to cancel out engine vibration and roughness Base Circle – On a camshaft, the side opposite a lobe (or cam) that is essentially the center of the camshaft from which the lobe rises Bearing – A device placed between two moving parts to reduce friction Bearing Clearance – The space between a bearing and moving component where a lubrication film can be maintained Before Top Dead Center (BTDC) – The location of the piston before it has reached the top of its stroke Piston location is measured in degrees of crankshaft rotation Ignition timing is normally specified in degrees BTDC (example: 12° BTDC) Bottom Dead Center (BDC) – The piston’s location at its lowest point of travel Brake Horsepower – Actual horsepower delivered by an engine at the crankshaft Normally measured by means of a dynamometer or pony brake Burned Valve – A valve that has been deformed or damaged by excessive heat Burned valves should not be reused Bushing – A removable, circular, one-piece component placed between two parts, either or both of which may move The bushing may absorb shock, perform bearing-like functions, or help to position parts Camshaft – A rotating shaft with lobes (cams) that open intake and exhaust valves Cam Followers – A valve train component found between the camshaft and valve stem Supported at one end, typically by a hydraulic lifter, allows the downward force of the cam lobe in the middle to push on the valve at the other end Carbon-Fouled – The buildup of carbon deposits on spark plug electrodes Fouled spark plugs are prone to misfire, causing a loss of power and poor performance and fuel economy Combustion Chamber – That portion of the cylinder between the piston and cylinder head in which combustion takes place Glossary-2 September, 2002 Engine Repair GLOSSARY Compression – Increasing the pressure of a gas by reducing its volume Compression Ratio – Volume of cylinder and combustion chamber with piston at Bottom Dead Center (BDC) as compared with volume of chamber at Top Dead Center (TDC) Compression Ring – Type of piston ring fitted to the uppermost grooves of a piston to prevent combustion gases from passing into the crankcase Most automotive pistons have two compression rings Compression Stroke – Upward movement of a piston that squeezes the air/fuel mixture into a tiny space, raising its pressure and causing it to explode with greater force when ignited Connecting Rod – Steel part connecting the piston to the crankshaft Coolant – A mixture, usually an ethylene glycol solution and water, used to carry excess heat from the engine to the radiator Coolant Recovery Tank – An auxiliary tank designed to receive the overflow when coolant in the radiator expands When coolant in the radiator contracts, the overflow is drawn back from the recovery tank Core Plug – A small metal disc that is force-fit into openings in the water jacket of an engine block If the coolant freezes, one or more core plugs may pop out to relieve pressure so that the block does not fracture Also called a freeze plug Crankcase – Component that houses the crankshaft and related components, a section of which is the oil pan Crankshaft – The component in an engine that converts the reciprocating power produced by the pistons into rotary power, which is transmitted to the drive wheels Named for the offsets, called “cranks” or “crank throws,” to which connecting rods are attached Cylinder Sleeve – A liner or tube inserted between the piston and cylinder wall or cylinder block to provide an easily renewable wear surface for the piston Cylinder sleeves that come in contact with coolant are referred to as wet sleeves Those that only contact the parent bore of the block are called dry sleeves Deep Skirt Block – A cylinder block whose skirt goes below the centerline of the crankshaft Detonation – In a gasoline engine, a sound created by ignition occurring prior to the spark The ignition commonly occurs in a recess in the combustion chamber and upsets the normal pressure pulse in the combustion chamber Also known as knock, ping, dieseling, after-run, and run-on Dieseling – A situation where a gasoline engine continues to run after the key is turned off Often referred to as “afterrunning.” Double Overhead Camshaft (DOHC) – An engine design in which two camshafts are located on top of the cylinder head One camshaft operates the intake valves and a second operates the exhaust valves Drop Forged – This type of forging is produced by impact or pressure that drives the hot and pliable metal to conform to the shape of the dies Drop forging uses a steam hammer or gravity drop hammer in combination with closed–impression dies Exhaust Port – Opening in the cylinder head through which exhaust gas leaves a cylinder Engine Repair September, 2002 Glossary-3 GLOSSARY Fillet – A rounded filling between two parts joined at an angle Four-Cycle Engine – Engine in which combustion in a cylinder occurs every other revolution of the crankshaft Strokes are: intake, compression, power, exhaust This cycle is also known as the Otto Cycle Freeze Plug – See “Core Plug.” Gallery – A passageway through which a liquid flows In automotive engines, the liquid is normally lubricating oil Glaze – An extremely smooth or glossy engine cylinder surface polished over a long period of time by friction of piston rings Harmonic Balancer – A device designed to reduce torsional vibration in the crankshaft of a multiple cylinder engine Hydraulic Lifter – A valve-lifter design using oil pressure to keep the lifter itself in contact with the camshaft on one end and the valve stem on the other This eliminates all clearance in the valve train when the engine is running Ignition – The start of burning of the air/fuel mixture in a combustion chamber Ignition Coil – The part of an ignition system that acts as a transformer changing pulsed low-voltage direct current in the primary winding to high-voltage spark impulses in the secondary winding It accomplishes this via a collapse of the magnetic field within the coils Impeller – An internal, enclosed wheel equipped with blades to move gas or liquid Intake Manifold – An engine component that conducts the air or air/fuel mixture from the throttle body assembly to the cylinders Intake Port – The opening in the cylinder head of an engine through which the air or air/fuel mixture enters the cylinder Intake Valve – The valve that opens the intake port, permitting the air or air/fuel mixture to enter the cylinder of an engine, and then closes, trapping it in the cylinder Intercooler – A device used to cool air compressed by a turbocharger or supercharger prior to entering the intake manifold Intercoolers rely on engine coolant (jacket water intercooler) or air (air-to-air intercooler) to cool the air going through them Also called a Charge Air Cooler Internal Combustion Engine – An engine that derives its power from fuel that is burned within the engine Journal – The smoothly finished part of a shaft that turns on a bearing Knock – Sound produced when a car’s air/fuel mixture is ignited by something other than the spark plug, such as a hot spot in the combustion chamber Light knock is normal in modern engines during heavy acceleration or under other high-load conditions, such as climbing steep grades Severe knock may be caused by fuel with too low an octane rating or by improper adjustment of the ignition system, and it will harm the engine Also called “detonation” or “ping.” Glossary-4 September, 2002 Engine Repair GLOSSARY Ladder Frame - A device used to support a number of bearing caps into one main structure Lash – The amount of play or free movement between parts, such as sets of gear teeth or valve train components Leakdown Rate – The period of time it takes for a valve tappet to collapse when being tested on a leakdown tester Lifter – Cylindrical metal component in contact with the camshaft on one end and the pushrod, rocker arm, or valve stem on the other Oil inside the lifter transfers the cam’s up-and-down action to the pushrod, rocker arm or valve stem by hydraulic action Lobes – Ear-shaped projections on a rotating camshaft Main Bearings – The bearings in which the crankshaft turns Manifold Vacuum – Low pressure in the intake manifold caused by the evacuating action of the pistons and cylinders Misfiring – Condition of an engine when one or more cylinders are not producing power Nodular Cast Iron – Also called ductile iron, this alloy is composed of gray iron combined with silicon and a small amount of magnesium and/or cerium before casting The graphite that forms during the fabrication process exists in nodular form This alloyed form of gray iron produces castings that are stronger and much more ductile, with mechanical properties approaching those of steel Typical applications for this material includes valves, pump bodies, crankshafts, gears, and other automotive and machine components Normally Aspirated – An engine without a turbocharger or supercharger The cylinder air charge pressure at the start of the compression cycle is very near or slightly below atmospheric pressure OHC – Abbreviation for overhead camshaft OHV – Abbreviation for overhead valve Oil Cooler – A small radiator that is used to cool oil Oil Pan – The metal housing at the bottom of the engine Serves as an oil reservoir, part of the crankcase Oil Pump – Device that forces lubricating oil through engine Oil Ring – Bottom piston ring that prevents an excessive amount of oil from going up past the piston Also called an oil scraper because it scrapes excess oil from the cylinder walls and lets it drain back into the oil pan Oil Scraper – See “Oil Ring.” Oil Seal – Component that prevents oil from leaking along a shaft or other moving part Oil Strainer – A screen mounted at or near the oil pump to prevent the passage of large-scale solid impurities being sucked up into the engine Overhead Camshaft (OHC) – Engine design in which the camshaft is mounted on the cylinder head Overheats – An abnormal condition under which the coolant temperature becomes excessive Symptoms include temperature warning light on, temperature gauge in the overheat range or coolant overflowing the overflow tank Engine Repair September, 2002 Glossary-5 GLOSSARY Ping – See “Knock.” Piston – Sliding metal component fitted to operate within a cylinder under hydraulic, mechanical, or combustion pressures In an engine, the piston is attached to a rod and, through that rod, transfers power to the crankshaft Piston Head – Part of the piston that is above the rings Piston Lands – Parts of the piston that are between the piston rings Piston Pin – See “Wrist Pin” Piston Ring Gap – The clearance between the ends of the piston ring Piston Ring Groove – Grooves formed in the piston into which the piston rings are fitted Piston Rings – Metal (usually made of steel, cast iron, or an alloy) rings mounted in grooves in a piston that bear against the cylinder walls The rings are designed to prevent compression forces from leaking past the pistons and into the crankcase, and keep excess oil from leaking past the pistons and into the combustion chambers Piston Skirt – That portion of the piston below the piston pin that is designed to take the side thrust of the piston Plenum – Chamber in the intake manifold where air is directed via the intake runners to the ports in the cylinder head Port – An opening in the cylinder head through which the air/fuel mixture and exhaust gases flow Powdered Metal – A substance used in the fabrication of metal pieces having intricate and precise shapes by the compaction of metal powders, followed by a densification heat treatment Power Stroke – Downward movement of the piston after the ignition of the air/fuel mixture in an engine cylinder Pre-Ignition – Undesirable ignition of the air/fuel mixture prior to when the spark occurs at the spark plug Often caused by glowing carbon deposits or hot spots in the combustion chamber; can harm the engine Also called “knocking” or “pinging.” Pushrod – A rod or tube in overhead valve engines that is fitted between the rocker arm and the valve lifter or tappet Sometimes referred to as a “push-tube.” Resonator – A secondary, sound-reduction device normally located behind the muffler in an exhaust system Rocker Arm – A valve train component that pivots (rocks) on a shaft or on a ball-shaped stud Rocker arms are used to change upward force on one end into downward force on the other in some valve trains Roller Lifter – A specially designed lifter that utilizes a roller bearing to contact the camshaft This lifter design generates a substantially lower friction than conventional tappets Scavenging – A siphoning effect created by the constant air flow that results from the combined force of the exhaust pulses in the header collector The constant flow creates a draw and pulls the exhaust out of the cylinders Seat – (1) The surface on which a part, such as a valve, rests (2) The final mating of parts after break in Glossary-6 September, 2002 Engine Repair GLOSSARY Serpentine Drive Belt – A single drive belt that drives all or most accessories Single Overhead Camshaft (SOHC) – An engine design with a single camshaft placed above the cylinder head Skirt – The hollow, lower part of a piston below the rings Slap – Sound made by a loose fitting piston as it strikes a cylinder wall Spark Knock – Sometimes referred to as pinging Abnormal combustion that is accompanied by an audible pinging noise Sprockets – See “Timing Gears.” Stroke – The distance a piston travels from Top Dead Center (TDC) to Bottom Dead Center (BDC) Tappet – A solid valve lifter with no hydraulic fluid See Lifter Throttle Body – The section of a fuel injection system that contains the throttle valve Timing Belt – A belt with cogs (squared teeth) that drives an overhead camshaft Timing Chain – A crankshaft driven chain that turns the camshaft to open and close valves at the proper time Timing Gears – The gears on an engine on which the timing chain runs or that form the connection between camshaft and crankshaft Top Dead Center (TDC) – The piston’s position at the highest point of travel Turbine – An internally enclosed wheel, equipped with blades, that is moved by the flow of gas or liquid Turbocharger – An assembly consisting of a turbine wheel that is driven by exhaust from an engine The turbine wheel drives a compressor wheel or impeller that draws air in and routes it to the engine’s intake air system Engine Repair September, 2002 Glossary-7 GLOSSARY Valve Clearance – The free play, or clearance between a valve and rocker arm or cam follower Valve Float – An undesirable condition in an engine when the valves cannot close before combustion begins Valve Guide – Passage in which the valve stem slides Valve Lash – Same as “Valve Clearance” Valve Overlap – Momentary interval between the intake and exhaust strokes when both the exhaust and intake valves are open Valve overlap helps to scavenge the cylinder of exhaust gases Valve Stem – The rod-like portion of a valve that moves within the valve guide Valve Stem Seal – The seal around a valve stem that prevents the excessive passage of oil down the valve guide Valve Seat Insert – A replaceable valve seat Vibration Damper – A weighted device, attached to a crankshaft, to smooth out power flow and prevent torsional vibration Volumetric Efficiency – A comparison between the actual volume drawn into a cylinder and the total amount it can actually hold if it were completely full Waste Gate – Component in a turbocharger used to relieve excess boost pressure Water Jacket – The hollow areas around an engine’s head and cylinders through which coolant flows and collects excess combustion heat Wrist Pin – A short rod that fits into two holes in the piston It passes through the small end of the connecting rod and holds the piston to the rod Also called a piston pin Glossary-8 September, 2002 Engine Repair ... GLOSSARY-1 ii September, 2002 Engine Repair INTRODUCTION DAY ONE Engine Repair September, 2002 Intro-1 INTRODUCTION ENGINE REPAIR CURRICULUM PATH ENGINE REPAIR CURRICULUM PATH Automotive... System Diagnosis – Classroom course code: 34S19T0 Engine Repair September, 2002 Intro-3 INTRODUCTION ENGINE REPAIR CURRICULUM The Engine Repair Curriculum Path consists of four types of courses... code: 32S03M0 – Engine Repair – Classroom course code: 32S05T1 – Servicing Overhead Cam Engines – FORDSTAR course code: 32S06F0 Intro-4 September, 2002 Engine Repair INTRODUCTION