Victa 2-Stroke Engine Manufacturing Report

The report details the manufacturing process of the Victa 2-Stroke engine, focusing on the materials used, casting methods, and the critical and non-critical parts of the engine block. It discusses the importance of engine blocks in converting chemical energy to mechanical energy and highlights the common casting method of sand casting. The report also reviews the mechanical properties required for engine block materials and the manufacturing operations involved in creating a functional engine block.

Running head: MANUFACTURING REPORT 1
Victa 2-Stroke Engine Manufacturing Report
Name
Academic Institution

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Victa 2-Stroke Manufacturing Report
Introduction
An engine block refers to the part of the engine which serves as the main structure and
houses the major components of any engine, including the cylinders, the crank and cum shafts, as
well as the case of the crank. This part also provides the passageways for the fluids that
participate in the combustion processes that give rise to the mechanical energy produced by
engines. Since it houses the numerous components that play a vital part in the engine process, it
is considered the largest part of the engine and takes up about a quarter of the total weight of the
engine. Developments in the field of engineering have continually bettered the performance of
engines since their invention in the mid-1800s, through an increase in their durability, power,
efficiency, and resistance to effects of wearing and friction. Engines are continually being
manufactured using light and strong materials like aluminium and cast iron alloys so as to give
the engine these desirable properties (Hetke & Gundlach, 2014). The former alloy is, however,
more common as it has an added advantage of being low cost, durable, having the ability to
withstand vibrations, high pressures, and temperature.
Materials and Casting Methods of Engine Blocks
Engine blocks ought to be designed and manufactured using materials with the desirable
mechanical properties to enable the blocks to function as expected. The important mechanical
aspects to consider when considering a material for the design of an engine block include the
tensile strength, the density of the material, its resistance to wear, corrosion, thermal
conductivity, castability, weldability, machinability, and ductility. All these factors vary
depending on whether the material will be used in diesel or petrol engines (Heusler, Feikus, &
Otte, 2011). The aspects of how easy the material is to machine and form are considered as they

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determine the cost and time taken to manufacture the engine block. With these aspects in mind,
the most common materials used in the manufacture of engine blocks are aluminium and iron
alloys, made through the low-cost casting method of sand casting, as characterized by the rough
surface of most of Victa 2-stroke engines. Research in material science has led to the discovery
that graphite cast iron is a new material that could be considered for manufacturing engine
blocks. Grey cast iron is the most common material used for diesel engines as it has an excellent
thermal and wear resistance, damping absorption, and machinability, while its cost is low
because of its availability. Aluminium alloys are common in petrol engines, because they have a
good machinability, corrosion, and thermal resistance, as well as a high strength and low weight,
although it is costlier than grey cast iron. Graphite cast iron which has been compacted, on the
other hand, has a commendable modulus of elasticity, damping absorption, and tensile strength.
It is however disadvantaged in its levels of machinability (Hetke & Gundlach, 2014).
Brief Description of Manufacturing Process
The most common method of casting engine blocks is sand casting, where a sand mold is
used, made from either metal, wood, or resin is reused to fabricate a number of molds. The sand
is combined with a bonding agent made from clay and water, so it holds the shape of the mold,
molten alloy is poured in, and the mold is compacted by vibrating it so as to remove the air
bubbles. It is then set aside to cool for a set period of time after the molten alloy has cooled into
the desired shape and dimension, the mold is separated to release the pattern of the engine block
that has been manufactured in the sand casting method. The method is preferred because of its
low cost and its ability to create very complex shapes and molds. The casted mold is then taken
through a few other machining processes to dimension it appropriately and to finish the surfacing

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processes using programmed milling and boring machines for increased accuracy (Hetke &
Gundlach, 2014).
Flowchart
(Heusler, Feikus, & Otte, 2011).
Order of the Manufacturing Operations
Although die casting is also used in the manufacture of engine blocks, sand casting is the
most common method due to its low cost since the dies never wear out as the dies in die casting.
Green sand is mainly utilized meaning that the sand utilized is wet as the bonding agent used is
made up of clay and water. The sand dies are mainly made using the cope and drag pattern,
where the mold is made from two pieces of the pattern that are carefully aligned when one-half is

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filled with the molten alloy and then the second piece is filled as well. The molds ought to be
freshly prepared for each casting through packing sand into the first half of the mold and around
the pattern to emulate the shape of the exterior of the casting. After the mold is compressed, the
pattern is removed to leave behind a cavity that is in the same shape as the expected casting.
The cavity that has been left behind is then lubricated, so as to enable the process of removing
the final cast simple, and also enable the flow of the molten alloy to all of the required areas. It
also aids the final casting to have the desired surface finish in the areas where there is an
impossibility of the finish processes reaching, within the newly casted engine block. The
lubricant chosen for every cast is different as it is determined by the temperature of the molten
allow metal that will be used in that specific casting process and also the sand mixture ratios that
are utilized for that specific pattern and casting. The molten metal alloy is then poured into the
mold through a manual or automated ladle, and it is then aligned and clamped (Heusler, Feikus,
& Otte, 2011). Automating the process ensures that enough amount of molten metal is poured
into the cavity to make a uniform cast. The molten metal is thus allowed to cool and solidify,
thus forming the final shape and dimensions of the cast. This process is usually allowed a set
amount of time. The most common defects in this process include incomplete parts where the
molten metal did not reach, cracks and shrinkages. The sand mold is then broken through
shaking and vibrating the mold after it has cooled completely and the cast is released. The excess
dimensions in the casting are then trimmed where the waste is recycled or discarded. The new
casting is then taken through other processes like heat treatment, forming, or machining, so as to
obtain the final product. Inspections ought to be carried out, to avoid using a defective casting
and assess if it attained has the required dimensions and thickness. Finishes such as boring holes
for screwing and bolting are then done on the new casting.

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Critical and non-Critical Parts of the Engine Block
As earlier explained, the engine block is a major component of the engine, as it is the
housing component of the different components that make up the engine and participate in its
ability to convert chemical energy to mechanical energy. The vital roles of the engine block
include guaranteeing the engine its stability to convert chemical energy into mechanical energy,
lubricate the engine to achieve efficiency in all of its operations, as well as controlling the
temperature within the engine to guarantee efficiency and effectiveness of the engine. This
explains why the engine block ought to be fabricated and manufactured in a preset set of
conditions, as its role is vital to the success and efficiency of the engine operations (Heusler,
Feikus, & Otte, 2011). The engine block thus plays a vital role in collaboration with the major
components of the engine, including the cylinder heads, flywheel, oil sump, and the timing case
in diesel engines.
With the functions of the engine block in mind, the critical parts of the engine block are
those that actively contribute to its efficiency in its participation as part of the engine. These are
mainly the oil and water lubrication vents and galleries that allow for the transfer of oil
throughout the different parts of the engine, thereby achieving lubrication of the vital
components of the engine. This also ensures that the engine is continuously cooled, and thus
maintaining the ambient temperatures of the engine at an optimal temperature of the engine.
Another key component of the engine block is the cylinder block unit that incorporates the walls
of the cylinder, cylinder sleeves and the cooling vents in the cylinder walls. It also entails the
passages where the crack shafts and the cum shafts that will be installed. The non-critical parts of
the engine blocks are the screwing and bolting holes used to place the different components of
the engine in place so that the engine can carry out its role. They also include the screws used to

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hold the different components in place, since the engine is made up of different critical
components that enable the engine to convert chemical energy in the cylinders to mechanical
energy that is emitted at the flywheel. Both the critical and non-critical parts of the engine block
enable it to carry out its primary and secondary functions, so as to contribute to its ability to
collaborate with the other vital parts of the engine to effectively and efficiently convert chemical
energy to mechanical energy used to drive different machines (Hetke & Gundlach, 2014).
Photos of Victa 2-Stroke Engine

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References
Heusler, L., Feikus, F. J., & Otte, M. O. (2011). Alloy and casting process optimization for
engine block application. AFS Transactions, 109, 443-451.
Hetke, A., & Gundlach, R. B. (2014). Aluminum casting quality in alloy 356 engine
components. American Foundrymen's Society, Inc, Transactions of the American
Foundrymen's Society,, 102, 367-380.