Group 10 - GM V-6 Engine Gate2
Gate 2: Preliminary Design Review
Causes for Corrective Action
Group 10 and 11 were both assigned to analyze this V6 engine. Group 11dissected the entire engine and Group 10 decided it would make the most sense to document the reassembly process. This way both assembly and dissection could be documented. The assembly of the engine went exactly as planned. The group met at 6:30pm on Tuesday October 19th and Thursday October 21st to reassemble the engine. Group 11 had previously dissected the entire engine and the whole process was discussed in detail, however members of Group 10 were not there during the dissection. Assembling the engine was slightly more difficult than the dissection process because we did not see each piece be removed, the entire assembling process took about 5 hours. The group used their previous knowledge and mechanical skill to correctly reassemble the engine. When everything was back together there were no extra pieces. Difficulties came from having to find all the proper bolts to fasten each part to the engine block. Almost every part was properly labeled in plastic bags but a few parts were still loose. The group worked together very well. Everyone had a job and this allowed us to quickly and efficiently complete the assembly.
Most of the assembly could be done with simple tools. The only exception was a ring compressor was used to reinstall the pistons and a valve spring compressor was needed to install each valve spring. The harmonic balancer also required a special press to press it back on to the crankshaft. We used 1/4" and 3/8" drive ratchets with metric size sockets. A power drill was used to fasten on the timing chain cover. The gasket around the cover made it difficult to use ratchets so the power tool was used.
Product Assembly Plan
The table below documents the procedure that was taken to dissect a GM V6 engine. Each step includes the part that is to be removed, which tool(s) will be used, and how difficult the step is on a scale of 1 to 5. Any additional concerns about removing the part are made in the "Notes" column.
Quickly and easily installed by hand
Quickly and easily installed using tools
Easily installed, but time-consuming or repetitive
Required moderate force, skill, or special tools
Required excessive force and time
The Dissection Process
|Step||Part Installed||Difficulty||Tools Used||Quantity / Size of Bolts Installed||Notes||Photos|
|1||Oil Pump||1||Socket Wrench||2 x T-20 Torx Bolts||Includes mount, pump, drive gear||(Image#11)|
|2||Crankshaft||1||Socket Wrench||8 Hex Bolts||Crankshaft is held in place by the main bearing caps.||(Image#12)|
|3||Pistons||1||Socket Wrench, Ring Compressor||2 x T-20 Torx Bolts||Piston rings had to be compressed before they could be installed into cylinders. Installation was very repetitive but relatively simple. Each piston had an indicator mark that pointed to the front of the engine. Cylinders were numbered odd on the left bank and even on the right relative to the flywheel.||Image #9|
|4||Oil Pan||2||Socket Wrench||12 x 12mm||Any Notes||(Image#19,20)|
|5||Camshaft||2||Socket Wrench||2 T-20 Torx Bolts||Camshaft was easily slid into place and fastened with plate.||(Image#10)|
|6||Distributor Shaft||2||none||none||Plastic, removed by hand||(Image#15,16)|
|8||Crankshaft Pulley||1||Socket Wrench||3 x 14 mm||one bolt missing||Picture|
|9||Camshaft Sprocket||2||Socket Wrench||3 x 13 mm||(Image#13)|
|10||Water Pump||2||Socket Wrench||4 x 14 mm||Photo|
|11||Balancing Shaft||2||Socket Wrench||2 x T30 Torx||Photo|
|12||Plastic Lifter Covers||1||Socket Wrench||4 x 10 mm||Rotated engine so lifters were horizontal to install (Image#18)||Photo|
|13||Lifters||1||none||none||placed by hand into lifter holders first, then into engine||(Image#18)|
|14||Push Rods||1||none||none||dropped into place||(Image#18)|
|15||Rockers||1||Socket Wrench||12 x 14 mm||assembly required removal of several rockers to reattach heads||(Image#22)|
|16||Valves (2)||2||Socket Wrench||26 x 13 mm||(Image#22)|
|17||Exhaust Manifold (2)||1||Socket Wrench||10 x 14mm||(Image#1)|
|18||Valve Covers (2)||2||Socket Wrench||6 x 13 mm||Branded with Vortec name||(Image#25)|
|19||Intake Manifold||2||Socket Wrench||10 x 14 mm||(Image#10)|
|20||Upper Intake Housing||1||Socket Wrench||6 x 12 mm||(Image#24)|
|21||Electric Ignition||1||Socket Wrench||2 x 10 mm||(Image#10)|
|22||Throttle Body||2||Socket Wrench||3 x10 mm||(Image#23) Bolted on top of intake manifold|
|23||Harmonic Balancer||5||Pully puller/press, Wrenches||none||Very tight press fit, needed special pulley remover to take off and pulley press to put back on||(Image#26)|
Images of the Assembly Process
Source: Group 18 Fall 2009
Source: Group 11 Fall 2010
Post Dissection Analysis
Ease of Disassembly
Almost every part in the engine was intended to be disassembled. Engines frequently require service or maintenance to different parts so having parts that are easily disassembled makes it easy to carry out these tasks. The hardest part about service is accessing the parts. When the engine is installed in a vehicle many areas are hard to access. When it's removed everything is easily reached. The entire engine was disassembled and reassembled mainly using basic tools such as a socket wrench which every mechanic has a set of. There were only a few different sizes and types of bolts, all of which were very common. This makes it easy for a mechanic to take out a specific component of the engine to fix or replace it if it needs to be serviced.
Connection of Subsystems
The GM V6 engine has multiple subsystems, each of which are connected and work together to allow proper, overall function of the engine. The 2 major subsystems are the mechanical and the electrical subsystems. The mechanical system provides mechanical energy, which powers to the electrical system. Every moving part of the engine is connected to the crankshaft in some way. The pistons are connected directly to it with a shaft. As the fuel combusts and pressure changes in the cylinders, the pistons move back and forth, causing the crankshaft to rotate. The crankshaft is connected to pulleys and pumps by belts, which are connected to the alternator. As the crankshaft spins, the pulleys and belts provide electrical and mechanical energy to the alternator. Before this rotation occurs however, the initial function must be performed by the user. This function is to turn the key, which transmits a signal to the starter motor to initiate the spinning motion.
The subsystems are all connected by mass through the crankshaft. The crankshaft is a solid component which cannot be further disassembled, and it is shaped in such a way that as it spins the parts connected to it move in and out. The pistons are directly connected to it. As it rotates, it also spins the camshaft which then opens valves. Force from the valve springs hold the valves closed until the lifter presses up on a rocker, which in turn pushes down on the valve, opening it. The lifters ride up and down on the cams of the camshaft. The systems are connected by means of energy as energy is transmitted and converted throughout the engine. When the user turns the key, electric energy from the battery is transferred to the starter, which initiates the engine movement. Fuel and air are combined and combusted in the cylinders, which causes the pistons to move and transfer their mechanical energy to rotational energy in the crankshaft. This mechanical energy is transferred through the whole engine by means of direct contact with the crankshaft or by belts, pulleys, chains, and sprockets and powers systems such as the oil pump and the coolant system. The kinetic energy of the belts connecting the crankshaft to the alternator is converted to electrical energy by the alternator, which keeps the battery charged. The rotational energy of the crankshaft also powers the rotation of the camshaft. The spark plugs receive electrical energy from the battery and the distributor dictates which plug fires by spinning over contacts for each plug. A shaft that is connected to the camshaft by cogs is timed with the engine and synchronizes the sparks. The spark plugs are responsible for the combustion of the fuel/air mixture in the cylinders, which initiates the kinetic energy to move the pistons.
Each component of the engine is connected in such a way to ensure its efficient and proper functioning. The mechanical energy that runs throughout the engine is transferred through direct contact to each of its moving parts. Since everything is connected directly, every system is dependent upon one another. The movement of the pistons requires the combustion of fuel and air, which requires a spark from the spark plugs. The electricity used by the spark plugs cannot be discharged without the distributor, which results from the interaction of the crankshaft with other parts. The battery, which is required for the engine's ignition, is charged by mechanical energy that originates in the combustion of fuel. The way that each component is connected is necessary for the use of one major fuel source, allowing for the most efficient process possible. Since there are so many moving parts, some energy is lost to friction and proper lubrication helps decrease this loss.
When it comes to automobiles, society puts a high value on efficiency. An engine that consumes a smaller amount of fuel in a given time is usually valued highly by society because less money is required for fuel purchase. The direct connection of parts previously discussed is used in most manufactured engines because it is the most efficient. Economic factors such as fuel efficiency were kept in mind when designing the engine to increase popularity and sales.
The subsystems of the V6 engine are assembled into the shape of a “V”. This is the optimal formation to ensure that all the moving parts can receive power from the crankshaft which runs right through the middle of the engine block. The subsystems of the engine are also arranged for simplicity and ease of maintenance since engines need to be serviced frequently. Parts that most often need to be serviced, for example, the oil filter and air filter are arranged near the bottom and top to make them easy to replace. The subsystems included in this engine are not particular to what they cannot be near. However, once other systems are included such as the electrical and fuel systems, it becomes very important to arrange certain subsystems away from others. For example, the electrical and fuel systems must arranged far from the exhaust pipe since the heat from the pipe can ignite a fuel line or destroy an electrical system.
Functional Model of Engine System
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