Detroit Diesel 638 Series Diesel Engine Workshop Manual

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GENERAL INFORMATION SCOPE AND USE OF THIS MANUAL This manual contains complete instructions on operation, adjustment (tune-up), preventive maintenance and lubrication, and repair (including complete overhaul). This manual was written primarily for persons servicing and overhauling the engine. In addition, this manual contains all of the instructions essential to the operators and users. This manual is divided into numbered sections. The first section covers the engine (less major assemblies). The following sections cover a complete system such as the fuel system, lubrication system or air system. Each section is divided into subsections which contain complete maintenance and operating instructions for a specific engine sub-assembly. Each section begins with a table of contents. Pages and illustrations are numbered consecutively within each section. Information can be located by using the table of contents at the front of the manual or the table of contents at the beginning of each section. Information on specific sub-assemblies or accessories within the major section is listed immediately following the section title. SERVICE PARTS AVAILABILITY Service parts are available throughout the world. A complete list of all Detroit Diesel Corporation (DDC) distributors and dealers is provided in the Detroit Diesel Corporation World Wide Parts and Service Directory , 6SE280. This publication can be ordered from any authorized DDC distributor. The dealer must have the engine identification and model number (located next to the transfer pump) to fill a parts order. CLEARANCE OF NEW PARTS AND WEAR LIMITS New parts clearances apply only when all new parts are used at the point where the various specifications apply. This also applies to references within the text of the manual. The column entitled Limits must be qualified by the judgement of personnel responsible for installing new parts. THE FOUR-CYCLE PRINCIPLE The diesel engine is an internal combustion engine, in which the energy of burning fuel is used to drive the engine cylinders. Air is compressed in each cylinder, increasing its temperature. After the air has been compressed, a charge of fuel is injected into the cylinder, and the hot, compressed air ignites. See Figure 20000 . Page 1 of 17 Service Doc

The Four-Cycle Principle Intake Stroke During the intake stroke, the piston travels downward, with the intake valves open and the exhaust valves closed. The downstroke enables air from the intake manifold to enter the cylinder through the open intake valve. The turbocharger, by increasing the air pressure in the intake manifold, ensures a full charge of air is provided to the cylinder. Compression Stroke At the end of the intake stroke, with the exhaust valves still closed, the intake valves close, and the piston starts upward on the compression stroke. At the end of the compression stroke, the combustion chamber air has been compressed to occupy a space about one-twentieth the size it occupied at the start of the stroke. Thus, the compression ratio is 21:1. The air is compressed into a small space, causing the temperature of that air to rise. During the last part of the compression stroke and the early part of the power stroke, a small metered charge of fuel is injected into the combustion chamber. Almost immediately after the fuel charge is injected into the combustion chamber, the fuel is ignited by the hot air and starts to burn, beginning the power stroke. Power Stroke During the power stroke, the piston travels downward with intake and exhaust valves closed. As fuel is added and ignites, the pressure increases, forcing the piston down and rotating the crankshaft. Exhaust Stroke During the exhaust stroke, the intake valves are closed; the exhaust valves are open, and the piston is on Page 2 of 17 Service Doc

its upstroke. The burned gases are forced out of the combustion chamber through the open exhaust valve port by the upward travel of the piston. From the preceding description, it is apparent that the proper operation of the engine depends upon the two separate functions: first, compression for ignition, and second, that fuel be measured and injected into the compressed air in the cylinder in the proper quantity and at the proper time. GENERAL DESCRIPTION The Turbotronic 638 described in this manual is a four-stroke cycle, high speed, indirect injection (IDI) diesel engine. It uses an inline cast iron block and has six cast aluminum cylinder heads. The camshaft actuates via push rods the valves for both the intake and exhaust valves. Coolant is circulated by the water pump through the crankcase washing over the liners, filling the cylinder heads. It enters the collection pipes to reach the thermostat bypass valve. It is channeled off according to the water temperature: if below 805 C (1765 F), it sends the water to the water pump; if above, it sends it to the radiator and then on to the water pump. The lubrication system has a rotor-type pump which delivers oil from the sump via the oil suction pipe circuit, where it is kept under pressure by the pressure relief valve and forced through the various passages to lubricate all moving parts. Oil is cooled by an air to oil cooler connected to the filter body by delivery and return hoses. Oil is then filtered through the cartridge, which is fitted with a bypass valve that allows oil circulation even when the filter is clogged. Fuel is drawn from the fuel tank by a transfer pump fixed to the crankcase and operated by a lobe on the camshaft. Priming of the fuel pump is manual. The fuel passes from the pump through a cartridge filter and is delivered to the injection pump. The injection pump is a distributor type and fitted with a built-in centrifugal speed governor driven by a gear that is in turn driven by the camshaft gear. The injection pump is fitted with an automatic advance mechanism that allows for advance variation according to pump flow rate. An external pipe collects excess fuel from the injection pump and injectors and returns it to the fuel tank. ELECTRONIC CONTROL UNIT The electronic control unit (ECU) has been programmed to monitor many different circuits for diesel powered vehicles. If an engine problem is sensed by a monitoring device, an electrical signal is sent to the ECU where a diagnostic fault code will be logged. The diagnostic fault code will be stored in the ECU memory for eventual display to the service technician. The diagnostic fault code can be displayed using either of two techniques: flash code or by way of a hand held diagnostic data reader (available late 1996). For the ECU to log a diagnostic fault code, certain parameters must be present. The parameters may be a specific range of engine speed, engine temperature, and input voltage to the ECU. A diagnostic fault code for a monitored circuit may not always be logged by the ECU even though a fault condition exists. This event may happen when one of the diagnostic fault code parameters for the circuit Page 3 of 17 Service Doc

has not been met. A diagnostic fault code indicates that the ECU has recognized an abnormal signal in a circuit or system monitoring the engine while running. The diagnostic fault code will indicate the result of a probable cause, but never identify the failed component. GENERAL SPECIFICATIONS The general specifications for the Turbotronic 638 are listed in Table . See Figure 20004 for the cylinder designation and firing order. Table General Specifications for the Turbotronic 638 Cylinder Designation Firing Order ENGINE MODEL AND SERIAL NUMBER The engine model number and serial numbers are stamped on the cylinder block. See Figure 27782 . General Specifications Engine Family Total Displacement (L) 3.8 Total Displacement (in. 3 ) 231 Type Four-cycle Number of Cylinders 6 Bore mm (in.) 92 (3.62) Stroke mm (in.) 94 (3.7) Compression Ratio 21:1 Number of Main Bearings 7 Page 4 of 17 Service Doc

Engine Model and Serial Number REPLACING AND REPAIRING In many cases, a service technician is justified in replacing a part rather than repairing it. Reworking or reconditioning a part may save a customer considerable expense. Exchange assemblies such as injectors, fuel pumps, water pumps and turbochargers are desirable service items. Various factors such as engine application, hours in service and the next scheduled overhaul must be considered when determining whether to rework or replace a part. For convenience and logical order in disassembly and assembly, the various subassemblies and other related parts mounted on the cylinder block will be treated as separate items in the various sections of the manual. DISASSEMBLY A service technician can be severely injured if caught in pulleys, belts or the fan of an engine that is accidentally started. Take the following precautions before starting to work on an engine. 1.Engine Model and Serial Number Page 5 of 17 Service Doc

Before any major disassembly, drain the engine of lubricating oil, coolant and fuel. When performing major repairs or an engine overhaul, the entire engine should be mounted to an overhaul stand. At that point, engine subassemblies can be removed. When only a few items need replacement, it may not be necessary to mount the engine on an overhaul stand. Whenever parts are removed, they should be kept together for easy inspection and assembly. Items with machined faces, which can be easily damaged, should be stored on suitable wooden racks or blocks, or a parts dolly. CLEANING Before removing any engine subassemblies (but after removing electrical equipment), thoroughly clean the engine exterior. Then, after each subassembly is removed and disassembled, the individual parts should be cleaned. Thorough cleaning of each part is absolutely necessary before it can be satisfactorily inspected. Various items of equipment needed for general cleaning are listed below. Steam Cleaning A steam cleaner is indispensable for removing heavy accumulations of grease and dirt from the exterior of the engine and its subassemblies. Solvent Tank Cleaning A tank of sufficient size to accommodate the largest part that will require cleaning (usually the cylinder block) should be provided and provisions made for heating the cleaning solution. Fill the tank with a commercial heavy-duty solvent. Heat the cleaning solution to 82-93 ° C (180-200 ° F). Using a hoist, lower large parts directly into the tank. Use a wire mesh basket for smaller parts. Immerse parts until grease and dirt are loosened. To avoid personal injury, disconnect the battery or batteries from the starting system by removing one or both of the battery cables from each system battery. With the electrical circuit disrupted, accidental contact with the starter button will not produce an engine start. In addition, the electronic unit injection pump will be disabled, preventing any fuel delivery to the nozzle tips. If the engine is equipped with an air starter, drain the air storage tank and disconnect the air supply to the starter before beginning engine disassembly. NOTICE: Engine sensors, and other electronic components, may be damaged if subjected to the high temperatures of a solvent tank. Therefore, ensure that all electronic components are removed from engine assemblies before they are submerged in a solvent tank. NOTICE: Aluminum parts, such as flywheel housing, pistons, air intake manifold, oil filter adaptor and the camshaft gear access cover should NOT be cleaned in this manner. Mention will be made of special procedures Page 6 of 17 Service Doc

Chlorinated solvents such as 1,1,1 trichloroethane have been identified by the EPA (Environmental Protection Agency) as possessing ozone-depleting properties. Detroit Diesel recommends replacing 1,1,1 trichloroethane with environmentally friendly Tech Solv 340 branded solvent wherever the former solvent was used. Tech Solv 340 is a petroleum-based solvent which contains no chlorinated or fluorinated compounds, has a controlled evaporation rate, leaves no residue, is odorless, has a high flash point, and provides outstanding cleaning. To enhance its cleaning and drying properties, it may be heated to 5255 C (9775 F). Spills can be cleaned up with commercially available oil absorbents, and conventional waste treatment methods for petroleum-base products can be used when disposing of this product. Tech Solv 340 is manufactured by and available from the following supplier: Chemical Technologies, Inc.* 1610 Clara Street P. O. Box 1366 Jackson, MI 49204 Telephone: 800-688-8262 FAX: 517-782-2448 * We believe this source and their Tech Solv 340 solvent to be reliable. There may be other manufacturers of solvents that replace 1,1,1 trichloroethylene. Detroit Diesel does not endorse, indicate any preference for, or assume any responsibility for the solvents from these firms or for any such products that may be available from other sources. Rinsing Bath Provide a tank of similar size, filled with hot water, to rinse parts. Drying Parts may be dried with compressed air. Heat from the hot tanks will frequently dry the parts, making blow drying unnecessary. Rust Preventive If parts are not to be used immediately after cleaning, dip them in a suitable rust preventive compound. The rust preventive compound should be removed before installing the parts in an engine. when necessary. To avoid personal injury when blow drying, wear adequate eye protection (safety glasses or face plate) and do not exceed 276 kPa (40 lb/in. 2 ) air pressure. Page 7 of 17 Service Doc

Removal of Gasket Eliminator The gasket eliminator used on numerous mating surface joints in the Turbotronic 638 engine results in a very thin film that must be removed from both surfaces prior to reassembly. As many of the surfaces are aluminum and dimensionally critical, conventional scraping methods, or the use of emery cloth for removing gasket eliminator is not recommended. Four-inch, 3M Scotch-Brite Surface Conditioning Discs, used with an electric or air powered hand drill (with a speed of 15,000-18,000 r/min), have proven successful in removing the gasket eliminator without damaging the mating surfaces of engine parts. See Figure 20007 . Gasket Eliminator Removal INSPECTION A thorough parts inspection determines the parts to be reused and the parts to be replaced. While the engine overhaul specifications provided throughout the manual help indicate when parts should be replaced, the service technician must also exercise his judgment. Note: The parts must be fully cleaned prior to inspection. 1. Determine the clearance between the mating parts and the wear rate of each part. 2. Reinstall the used part if the current wear rate will maintain the clearances within the specified maximum allowable limits until the next scheduled overhaul. Note: Wear rate is determined by dividing the amount of part wear by the hours in service. In addition to making accurate parts measurements, the parts should also be inspected for cracks, scoring, chipping, and other detrimental conditions. For complete information on service parts availability, contact your local Detroit Diesel distributor. SAFETY PRECAUTIONS Page 8 of 17 Service Doc

The following safety measures must be observed when working on the Turbotronic 638 engine. Stands Stands must be used in conjunction with hydraulic jacks or hoists. Do not rely on a jack or hoist alone. When lifting an engine, make sure the lifting device is securely fastened. Also ensure that the weight of the load being lifted does not exceed the lifting capacity of the device. Glasses Wear appropriate safety glasses. Safety glasses are especially important when tools, such as hammers, chisels, pullers, and punches, are used. Welding Wear welding goggles and gloves when welding or using an acetylene torch. Ensure that a metal shield separates the acetylene and oxygen tanks. These must be securely chained to a cart. The exhaust products of an internal combustion engine are toxic. They may cause injury or death if inhaled. All engine installations, especially those within enclosed spaces, should be equipped with an exhaust discharge pipe so that exhaust gases are delivered into the outside air. An enclosed space must be adequately vented. Some means of providing fresh air into an enclosed space must be ensured. To avoid possible personal injury when arc welding, gas welding or cutting, wear required safety equipment such as arc welder's face plate or gas welder's goggles, plus welding gloves and protective apron, long sleeve shirt, head protection, and safety shoes. Always perform welding or cutting operations in a well-ventilated area. The gas in oxygen/acetylene cylinders used in gas welding and cutting is under high pressure. If a cylinder should fall due to careless handling, the gage end could strike an obstruction and fracture, resulting in a gas leak which could lead to fire or an explosion, both of which could cause personal injury or property damage or both. If a fall should result in the gage end breaking off, the sudden release of high pressure gas could turn the cylinder into a dangerous projectile, which could cause severe personal injury or property damage or both. Observe the following precautions when using oxygen/acetylene gas cylinders: 1. To avoid possible foot injury, always wear required safety toed shoes. 2. Do not handle tanks in a careless manner or with greasy gloves or slippery hands. 3. Use a chain, bracket, or other restraining device at all times to prevent gas cylinders from falling. 4. Do not place gas cylinders on their sides, but stand them right side up when in use. 5. Do not drop, drag, roll, or strike a cylinder forcefully. 6. Always close valves completely when finished welding or cutting. Page 9 of 17 Service Doc

Detroit Diesel 638 Series Diesel Engine Workshop Manual

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