Gate 4: Product Description

Figure 1: Complete Assembly of Tecumseh Engine

Group 22 - Tecumseh Engine Disassembly Process 2011

Project Management: Critical Project Review

Cause for Corrective Action

At this point in the project the strengths and weaknesses of each member of the group is easily recognizable. As the majority of the work on each assignment of our project lands on two or three group members, as explained in the paragraphs below, it becomes extremely difficult to focus our time on each section. This means that the amount of work done on the project is sometimes not done as thoroughly and as detailed as it could be. Giving the proper recognition to each member on the website should illustrate the unfair work load that our group had to deal with. With this said, each group member understands that group evaluations will be coming up soon and the members that worked hard and did their work should receive much higher gratitude when being graded.

Each member was given strict high expectations and was well aware of each assignment. Serious lack of effort by any group member was recognized by the group manager which resulted in a series of confrontations by the other group members. As the semester began to come to a close the group found it extremely hard to deal with the lack of responcibilty and poor group attendance at meetings. After multiple unsuccessful attempts to bring the group together, the group decided it would be best to move on and take on the responcibility as it would be more beneficial to the success of each assignment.

Some major drawbacks of the group include poor communication and poor meeting attendance. For example, Darroch Moorhead was not able to make it to both the product’s disassembly and reassembly of the engine and that made it extremely difficult for him to contribute to certain parts of the project. This problem was overcome by assigning him work to do separately that concerned more research based topics that allow him to do on his own and submit to the group for review. For the most part Darroch submitted satisfactory work but with the lack of meeting attendance this group member was of little contribution to the overall groups’ workload. With the project coming to a close, Darroch has been reminded and understands he needs to show a better effort in his coursework or else he will not receive the best evaluation.

Poor communication was another major disadvantage of one of the other group members that severely handicapped the group's performance. Sangjoon Bark is an international student that seems to have difficulty comprehending every part of the assignment and project. Although Sangjoon seemed to be interested in the project he failed to complete any assignment that was given to him. Our group found this member very hard to communicate with to get anything done. The group even set up a meeting to talk about his performance. After the confrontation, Sangjoon seemed to have an understanding that he was expected to participate more in every aspect of the groups’ decisions. As the project continued he still was unable to complete anything beneficial for our group. With time running out in our project our group decided it was best to distribute his work to the rest of the group as it would be more favorable to the grade on each assignment.

As for the other three group members, the group manager Ryan Sans and technical expert Matthew Whitman continue to do the necessary research and prepare each assignment with as much effort as they can to satisfy the rest of the groups weaknesses. They both also have prepared an entire presentation for the group as they were selected as the most knowledgeable members of the group to take on this role. Kevin Perez, our communication liaison also works with the group manager by putting in a great deal of work to create the website page while also completing his assignments on time with satisfactory effort.

Another problem we came across was the failure to follow directions on recent project assignments. Our group’s decision of evenly distributing the work amongst the rest of the group was a downfall as there was no cross examination of one another’s work before submission. On future assignments our group has decided to allow for at least two other members of the group to check over a member’s work before submission to reduce the amount of errors in one another’s performance.

Author: Ryan Sans

Product Archaeology: Product Explanation

Product Reassembly

Introduction

After the engine has been disassembled and examined the next step is to reassemble it. Taking into consideration the steps done throughout the disassembly process, the group worked backwards as much as possible recording each of the procedures and what obstacles were encountered. The data that was recorded during the assembly process are as follows:

Details

Figure 2: Tecumseh Assembly Layout

Details of the reassembly are provided to inform the steps taken which will allow any individual to read and follow.

Comparison

A comparison between the previous disassembly and original assembly with the groups assembly.As most engines made during the same time period, Tecumseh make their engines on an assembly line. Also similarly to most engine manufacturers, many of the assembly processes are done with high precision robot arms and sensors. this process is demonstrated on the following video link:

High Performance Engine Assembly

The engine in the video requires more presice and complex Assembly but process should not defer to much from the Tecumseh engine assembly.

Level of Difficulty

The rate of difficulty is ranged from 1 to 10:

1. Used no tools usually an easy insertion of the part.
2. Uses simple tools and required very little effort.
3. Tools were required .
4. Encounter obstacles but not too difficult to solve.
5. Tools are mandatory and assembly requires some effort.
6. Difficulty assembling part properly also time consuming.
7. Difficulty understanding part and assembly step.
8. Parts are delicate and require precision.
9. Complex components that require several tries for assembly.
10. Most complicated part that requires most attention and time with improvise assembly.

Tools Used

The tools required for the assembly, for most parts the tools used were same as the disassembly procedure, tools used are as followed:

• Flathead Screwdrivers
• Spacers
• 1/2 Sized Socket Wrench
• 1/4 Sized Socket Wrench
• 5/16 Sized Socket wrench
• 3/8 Sized Socket Wrench
• 7/16 Sized Socket Wrench

Author: Kevin Perez

Pre-Reassembly:

Before the reassembly of the product a Layout of the engine components was made by categorizing each piece to its relating fasteners and other components. For example, the 3/8 sized crankcase bolts are laid out next to the crankcase, as well as the 3 piston rings and 1/4 sized bolts that connect the piston to the crankshaft are laid out near the piston for simplicity during assembly.

Author: Ryan Sans

Table 1.

Tecumseh Engine reassembly procedure
Step #	Detail	Comparisons	Difficulty (1-10)	Tools Used	Image
1	Assembly of the Crankshaft: 1. Slide the crankshaft into the crankcase threaded side first.	Disassembly: The disassembly process and assembly process of the crankshaft are the same as the crankshaft slides in and out of the crankcase before the piston is unfastened on it. Original Assembly: With the exception of robot assembly of the crankshaft, the process is similar to groups assembly.	Range: 1 Reason: This process was very basic and required minimal effort	None	Figure 3: Crankshaft Figure 4: Crankshaft inside the crankcase
2	Assembly of the Piston: 1. Slowly wrap the first piston ring along the edge of the piston slot and pop the ring inside the piston' '. 2. Repeat process for the second piston ring as well as the piston’s oil ring. (During this process it was vital to gently piece the piston rings onto the piston as each ring is very brittle.) 3. Next slide piston into the cylinder slowly until the piston rings hit the top of the cylinder. 4. Squeeze each ring one by one while lowering the piston into the cylinder with the use of two Flathead screwdrivers to edge them into the cylinder carefully. 5. Once the piston is inside the cylinder assemble the connecting rod to the crankshaft by using a 1/4 socket wrench.	Disassembly: The assembly differed from the disassembly process because when the group disassembled the piston the piston easily slid right out of the cylinder. During the assembly process the piston was harder to put into the cylinder as each ring had to be carefully pushed together by the use of two screwdrivers. Original Assembly: The piston brittle rings are delicate parts that during the time period the engine was produced it would take human interaction. today there are machines that could assemble the rings with more precision and less chances of braking. To prevent the obstacle that the group encounter the rings would have had to be heat it up to compress them this would solve the problem of the strain that the rings encounter through assembly and create a perfect fit of the piston through the cylinder.	Range: 9 Reason: It was very difficult to squeeze the rings into a position that allowed for the piston to slide in to place. This step proved to be one of the hardest in the assemble process	• 2 Flathead Screwdrivers • 1/4 Sized Socket Wrench	Figure 5: Piston Figure 6: Piston Assembly into the cylinder Figure 7:Piston connecting to Crankshaft
3	Assembly of the Valves: 1. First slide each valve through the valve slots on the top of the piston head, each valve should slide in with ease. 2. Next piece the spring and the end cap together inside the valve slot through each valve. 3. Compress each spring and slide the end of each valve through the end cap using two flathead screwdrivers as levers, this allows the spring to be compressed at all times. 4. Once the valves are in place, slide each valve follower through the bottom of the crankcase. This will allow the camshaft to open each valve upon contact. 5. Finally align the valve cover over the valve opening and fasten the 5/16 sized bolts on both sides of the case.	Disassembly: The disassembly process of the valves is the same as the assembly process only backwards in sequence. In the disassembly process the cover then valve followers are taken out first then then end cap, then then spring and valve. In the assembly process the valve is placed into the slot first then the spring and end cap then the valve followers and cover. Original Assembly: The Assembly of the valves original assembly would be made by robots arms attaching both valves at the same time with lesser time and less struggle than groups assembly.	Range: 10 Reason: This step also proved to be very difficult. The challenging part was putting the valve springs back in place, which required two patient group members equipped with flat screw drivers. This step took approximately five minutes of adjusting the spring until it was securely in place.	• 2 Flathead Screwdrivers • 5/16 socket wrench	Figure 8: Springs and Valves Figure 9: Valve Assembly inside the engine Figure 10: Springs attached with the Valves
4	Assembly of the Camshaft and Oil Pump: 1. Insert the camshaft with the cams facing the crankcase into the slot provided next to the crankshaft, make sure the gears line up with the crankshaft. 2. Once the camshaft is in place, slide the oil pump on top of the gear.	Disassembly: The assembly process is the same as the disassembly process as both parts slide easily onto the spots provided without any tools. Original Assembly: Thecamshaft would be assembled by robot arms which sensors and high precision, it would be position in a manner that would make the engine function at the correct timing, the timing of the valves and piston function needs to be precise for the engine to be 100% efficient. The oil pump would have been a simple assemble using same method as group.	Range: 1 Reason: This step was very simple and required minimal effort.	None	Figure 11: Camshaft Figure 12: Camshaft Assembly inside Crankcase with Crankshaft Figure 13: Camshaft and Oil Pump Assembled
5	Assembly of the Governor: 1. Insert washer onto the rod provided for the governor. 2. Next push the c-clip into the bottom slot using a flathead screwdriver. 3. Slide the plastic governor gear on top of the c-clip. 4. Once the governor gear is on the rod, slide the governor spool on top of the gear. Make sure the governor spool is placed on top of the metal pieces of the governor gear. 5. Finally insert the second c-clip onto the top c-clip slot.	Disassembly: The disassembly process is the same as the assembly process. However it is also backwards in sequence. During the assembly process, the washer and first c-clip are inserted first then the governor gear and spool is slid onto the rod and then the last c-clip. During the disassembly process the top c-clip is detached first and then the governor’s spool and gear are slid off along with the washer and bottom c-clip. Original Assembly: The governor is a simple component and it would be put together in the same manner as how the group did, with more ease with the help of machines.	Range: 5 Reason: This step was made more difficult due to the initial condition of the governor. The c-clips were missing and had to be replaced. The new c-clips were also difficult to slide on to the governor but once they were situated correctly they had a perfect fit.	• 1 Flathead Screwdriver	Figure 14: Governor Figure 15: Governor Assembled with the Crankcase Cover
6	Assembly of the Crankcase: 1. Place the cover of the crankcase on the assembly so the crankshaft goes through the hole allotted for it. 2. Slowly close the case so the oil pump fits in its slot and the governors gear is threaded with the gear from the cam shaft. 3. Fasten the six 3/8 size bolts to the top of the crank case.	Disassembly: The assembly process was similar to the disassembly process, however required more precision to ensure the threads from the governor aligned with the threads of the camshaft. Original Assembly: The crankcase would be a simple task since alignment of the oil pump and governor threading are done before crankcase sealing. The bolts are all done at the same instance with a robot arm.	Range: 5 Reason: The difficult portion of this step was ensuring that both the oil pump was in the correct slot and the camshaft gear was threaded with the gear from the crankshaft	• Size 3/8 Socket Wrench	Figure 16: Crankcase and cover Figure 17: Crankcase and cover Assembled
7	Assembly of the Piston Casing: 1. Place the piston head cover and the piston gasket on top of the cylinder. 2. Fasten the eight 1/2 bolts to the top of the piston casing.	Disassembly: The assembly process was the same as the disassembly process with the exception of aligning the piston gasket with the holes for the bolts. Original Assembly: This assembly is similar to the crankcase assembly with the difference of the gasket alignment and the number of bolts.	Range: 4 Reason: This step was rather easy but somewhat time consuming. The bolts screwed in cleanly and the piston head cover closed nicely.	• Size 1/2 Socket Wrench	Figure 18: Piston Cylinder and Gasket Figure 19: Piston Head Cover Fastened to the Piston Cylinder
8	Assembly of the Crankcase Breather: 1. Slide the crankcase breather into the hole on the top of the engine. 2. Next align the gasket and place the crankcase breather on top of the gasket aligning with bolt holes. 3. Using a 5/16 socket wrench fasten each bolt onto the top of the engine.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing in each bolt. Original Assembly: With the exception of robot assembly of the crankcase breather, the process is similar to groups assembly.	Range: 3 Reason: This step was also very easy and required minimal effort.	• 5/16 Socket Wrench	Figure 20: Crankcase Breather Components
9	Assembly of the Muffler (Exhaust): 1. Line up the 7/16 sized bolt holes to each hole of the muffler. 2. Fasten each bolt using a 7/16 sized socket wrench.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing in each bolt. Original Assembly: With the exception of robot assembly of the muffler, the process is similar to groups assembly.	Range: 2 Reason: This step required the muffler to be placed on the right valve intake/exhaust holes, after figuring this the rest of the assembly consisted on basic effort and was easily completed .	• 7/16 Socket Wrench	Figure 21: Muffler Figure 22: Muffler Assembled to the Side of the Piston Casing on the Exhaust side of the valves.
10	Assembly of the Intake Manifold; 1. Align each hole of the intake manifold. 2. Using two screws acquired from the garage fasten each one to the side of the piston casing.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing in each bolt. Original Assembly: With the exception of robot assembly of the intake manifold, the process is similar to groups assembly.	Range: 2 Reason: This step required little effort except for tracking down the proper replacement screw.	• 1 Flathead Screwdrivers	Figure 23: Intake Manifold Figure 24: Intake Manifold Assembled
11	Assembly of the Flywheel: 1. The Flywheel is put through the threaded Crankshaft end that sticks out of the Crankcase. 2. A washer and a nut is used to fastened the Flywheel with the Crankshaft. 3. Make sure the nut is tight enough so the Flywheel and the Crankshaft would rotate as one.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing the knot. Original Assembly:	Range: 1 Reason: This step was basic and required minimal effort. The flywheel fit nicely and the nut fit perfectly.	None	Figure 25: Flywheel Figure 26: Flywheel Assembled
12	Assembly of the Carburetor: 1. Delicately place the small spring valve into the carburetor by sliding the wire behind the metal piece provided and slide the valve carefully into the valve slot by closing the carburetor float. 2. Next slide the carburetor cover on. 3. Insert a washer and fasten the carburetor together with one 1/2 bolt with a socket wrench. 4. Once the carburetor is pieced together align the carburetor gasket along with the two bolts onto the intake manifold and fasten with a 3/8 socket wrench.	Disassembly: The assembly process of the carburetor was more difficult as the tiny spring valve was needed to be placed inside the carburetor gently. During the disassembly process the spring valve was easily taken out of the carburetor. Other differences include the unscrewing and screwing of each bolt on the carburetor. Original Assembly: The carburetor is a complex devise as the small spring valve needs to be properly installed with of the machines this process would take less time and installation would be more precise since the carburetor is one of the most sensitive a valuable part of the engine. The rest of the assembly should be the same as group's.	Range: 7 Reason: The difficulty increased with this step due to the delicacy of the spring valve. After the spring valve was securely in place, care was taking to ensure it would not pop out.	• 1/2 Socket Wrench • 3/8 Socket Wrench	Figure 27:Carburetor Disassembled Figure 28:Carburetor Spring Valve Figure 29:Carburetor Assembled and on Engine
13	Assembly of the Magneto and Spark Plug: 1. First align and fasten slightly the 5/16 bolt holes on the magneto to the piston casing. 2. By utilizing spacers, make sure the fly wheel magnet is as close to the magneto without touching it and screw the 5/16 bolts into the piston casing all the way. 3. Screw the J8C Champion spark plug into the hole provided on the piston casing and cap it off with the magneto cap.	Disassembly: The disassembly process does not include the careful spacing of the magneto and fly wheel magnet. Other differences include the screwing and unscrewing of each bolt. Original Assembly: With the exception of robot assembly of the magneto and spark plug, the process is similar to groups assembly.	Range: 4 Reason: It was somewhat difficult to ensure the magneto was properly spaced from the flywheel despite the use of the spacers. After a couple of adjustments, we were able to move the magneto as close to the flywheel as we could while still allowing the flywheel to rotate freely.	• Spacers • 5/16 Socket Wrench	Figure 30: Magneto and Spark Plug Figure 31:Magneto Fastened to Engine Figure 32: Magneto and Spark Plug Assembled
14	Assembly of the Throttle: 1. Line up each hole on the throttle to the intake manifold and fasten each 5/16 bolt with the necessary socket wrench. 2. Connect the governor and throttle using a wire by sliding the wire through each of the holes provided on the governor and the throttle.	Disassembly: The assembly process requires a strategic maneuvering of the wire onto each part. During the disassembly process the wire was not even attached to the throttle properly and was easy to detach from the engine. Original Assembly: With the exception of robot assembly of the throttle, the process is similar to groups assembly.	Range: 2 Reason: Because the throttle was not originally assembled the correct way, we were initially unsure of how to assemble it. After tinkering with the set up for a minute or two, we realized where the wire should be attached and were able to successfully connect the throttle to the governor.	• 5/16 Socket Wrench	Figure 33: Throttle Figure 34: Throttle Assembled Figure 35: Throttle Attached to Magneto
15	Assembly of the Filter: 1. Using a 1/4 sized socket wrench fasten the bolts of the air filter to the side of the carburetor by placing the air filter on top of the throttle. 2. Next attach the crankcase breather to the air filter by sliding the hose component onto the filter. 3. Note: The container top of the air filter is not attached until after the engine case.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing each bolt. Original Assembly: With the exception of robot assembly of the filter, the process is similar to groups assembly.	Range: 2 Reason: This step was very simple and was not very time consuming. The filter fell in place nicely and the bolts fit well.	• 1/4 Socket Wrench • Philips Head Screwdriver	Figure 36: Filter Figure 37: Filter Assembled
16	Assembly of the Engine Case: 1. Carefully insert the case onto the top of the engine sliding the past the fly wheel and through the air filter component. 2. Align the case with the each of the four bolt holes and fasten two of them with a 7/16 socket wrench and the other two with a 1/4 socket wrench. 3. Note: The filter is inserted into the air filter container and the top of the air filter is attached to the container by inserting two tabs on the engine casing and screwing in one small screw on the side of the container.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing in each bolt. Original Assembly: With the exception of robot assembly of the engine case, the process is similar to groups assembly.	Range: 5 Reason: Because of the wear on the engine case, two members had to force the case into position so that the holes lined up with the holes on the engine. This was more frustrating than difficult but did not take more than five minutes to complete.	• 7/16 Socket Wrench • 1/4 Socket Wrench	Figure 38: Engine Case Figure 39: Engine Case and Filter Cover Assembled
17	Assembly of the Recoil Starter: 1. The recoil starter cover is inserted on top of the engine cover over the flywheel. 2. Next fasten one 1/4 bolt onto the side of the engine cover with a socket wrench. 3. Attach the cap of the flywheel by sliding the cap’s rod into the recoil starter.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing in each bolt. Original Assembly: With the exception of robot assembly of the recoil starter, the process is similar to groups assembly.	Range: 2 Reason: The recoil starter fell into place nicely and the bolts were very manageable.	• 1/4 Socket Wrench	Figure 40: Recoil Starter Figure 41: Recoil Starter Assembled
18	Assembly of the Oil Pipe: 1. Using one 5/16 bolt and a socket wrench the oil pipe is fastened to the engine cover.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing in each bolt. Original Assembly: With the exception of robot assembly of the oil pipe, the process is similar to groups assembly.	Range: 1 Reason: This step was very easy and required little effort.	• 5/16 Socket Wrench	Figure 42: Oil Pipe
19	Assembly of the Gas Tank: 1. We placed the gas tank on the engine so that the oil pipe went through the hole allotted for it. 2. We then used three 5/16 size screws to secure the gas tank to the engine.	Disassembly: The assembly process of this step is the same as the disassembly process with the exception of screwing and unscrewing in each bolt. Original Assembly: With the exception of robot assembly of the gas tank, the process is similar to groups assembly.	Range: 2 Reason: The only difficult part of this step was finding the proper screws. Initially we used one of the gas tank screws to secure the engine case. Once we realized the mistake, we switched the screws and secured the gas tank without any other difficulties.	• 5/16 Socket Wrench	Figure 43: Gas Tank,Gas Tank and Oil Pipe Covers Figure 44: Gas Tank Assembled
20	Assembly of the Pulley: 1. Insert the keyway onto the top keyway port. 2. Next slide the pulley onto the crankshaft directly over the first keyway, making sure both the keyway slot and keyway on the crankshaft line up.	Disassembly: The disassembly process was extremely more difficult than the assembly process of the pulley. During the disassembly of the pulley the group had to go the workshop in Jarvis and use a wheel puller to detach the pulley from the crankshaft; which incidentally was the hardest process of the disassembly. During the assembly process of the pulley the group was able to slide the pulley onto the crankshaft after polishing both the crankshaft and inside the pulley. Original Assembly: With the exception of robot assembly of the pulley, the process is similar to groups assembly.	Range: 1 Reason: This step was very easy, especially when compared to the disassembly process. The key fit perfectly and the pulley was slid on to the crankshaft smoothly.	None	Figure 45: Pulley Figure 46: Keyway Figure 47: Pulley Assembled

Authors: Ryan Sans, Kevin Perez, Matthew Whitman

Design Revisions

1) Index the Spark Plug

Indexing the Spark Plug simply consists of ensuring the spark plug is pointed in the correct direction. When a spark is emitted, it is better for combustion if the spark plug is pointing towards the center of the cylinder as opposed to the wall of the cylinder. This is achieved by making sure the ground electrode on the spark plug is facing towards the center of the cylinder upon installation. This revision is motivated by economic, societal and environmental factors, as it provides for a more complete combustion, decreasing harmful emissions and increasing the engine’s efficiency as well as power.

Figure 11: Indexing the Spark Plug

2) Aluminum Casing

The second design revision would be to use aluminum for the casing of the engine instead of steel. It would make the engine lighter, rust resistant, and cheaper to buy which represents an economic design factor. Dispite aluminums high costs and lack of durability when compared to steel, it can still be used for the simple aplication of casing the engine and would allow the product to decrease in cost. This is influenced by the societal factor as cost is a very important feature of the product in today's society. The use of aluminum would make the engine more vulnerable to impacts, however assuming the intended use is for a lawn mower, getting the engine damaged from an impact is not very likely.

Figure 12: Aluminum vs. Steel

3) Utilize Double Angle Valve Joband Increase Tensile Strength in Valve Springs

A double angle job entails creating more seats for the valve to sit on by making the current valves and valve seats angled. By using a double angle job, the valve creates a tighter seal over the cylinder and decreases the amount of air/fuel mixture that could escape during the compression stroke. Also, by increasing the tensile strength of the valve springs the seal will be even tighter. These revisions are motivated by economic and environmental factors as they decreases the amount of emissions from the engine as well as increase efficiency. Utilizing double angle valves would have to be properly researched by the manufacturer to make sure the revision will be profitable for the company. In other words, because the intended use for this engine is to be placed in a lawn mower the company might not consider double angled valves as the efficiency would only be increase by a small amount. Also the tensile strength of the valve springs would need necessary research to find the optimum strength between too strong and too weak. This is due to the fact that stronger springs require a larger amount of force to open them creating a need for higher torque but will shut faster leading to less harmful emissions.

Figure 13: Double Angle Valve Job

4) Increase Circumference of Flywheel

By increasing the size of the flywheel, it will induce a larger moment, which will allow for an easier start to the engine. While using the pull cord, the user will not have to pull as hard in order for the engine to start up. Although this will increase the cost and size, it will attract more consumers due to the fact many people don’t enjoy trying to start their lawn mower. Therefore it is an advantage to increase the cost and increase the functionality of the product. By appealing to more consumers, this revision is motivated by a social factor.

Authors: Darroch Moorhead, Matthew Whitman and Ryan Sans

Researched and Presented by: Ryan Sans and Matthew Whitman

Wiki Formatting: Kevin Perez