Download Engineering Fundamentals Exam 2025 and more Exams Engineering in PDF only on Docsity!
Everything You Need to Know About the
Engineering Fundamentals Exam 2025:
Disciplines, Duration, and Study Plans
Question 1: When discussing intake and exhaust port designs: Technician A says larger ports will increase an engine's torque at low engine speeds. Technician B says larger ports will increase torque at high engine speeds. Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: The correct answer is B. Larger intake and exhaust ports allow for greater airflow into and out of the cylinders. This increased airflow becomes more beneficial at higher engine speeds when the engine demands more air in a shorter amount of time. Smaller ports create higher intake velocities at lower RPMs, which can improve cylinder filling and thus low-end torque. Question 2: What is flame propagation in an internal combustion engine? A) The rate at which the piston moves during the power stroke. B) The process of compressing the air-fuel mixture in the cylinder. C) The movement of the flame front away from the spark plug across the combustion chamber after ignition. D) The expulsion of exhaust gases from the cylinder. Rationale: The correct answer is C. Flame propagation describes how the combustion process
spreads throughout the combustion chamber after the spark plug ignites the air-fuel mixture. Question 3: Straightening a warped cylinder head typically involves bolting it to a straightening plate with shims to induce tension. The cylinder head is then heated to a maximum of ____ before allowing it to cool slowly. A) 200°F B) 350°F C) 500°F D) 650°F Rationale: The correct answer is C. Heating the cast iron cylinder head to no more than 500°F allows the metal to become more pliable for straightening without causing significant metallurgical changes or weakening the material. Question 4: Two technicians are discussing a cracked cast iron cylinder head: Technician A says that some cracks can be welded successfully. Technician B says that some cracks can be repaired by pinning them. Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: The correct answer is C. Both welding and pinning are established methods for repairing cracks in cast iron cylinder heads, depending on the location, size, and nature of the crack. Welding involves filling the crack with molten metal, while pinning involves installing a series of overlapping threaded pins across the crack to hold it together. Question 5: To begin cylinder head component reassembly:
C) Rotor housing D) Eccentric shaft Rationale: The correct answer is C. In a rotary engine (Wankel engine), the rotor housing forms the combustion chambers and is analogous to the cylinder block in a reciprocating engine. Question 8: Down-flow radiators: A) Have coolant flow horizontally through the core. B) Utilize a surge tank mounted separately. C) Have tanks located on the top and bottom, with coolant flowing vertically. D) Are typically used in older vehicles only. Rationale: The correct answer is C. Down-flow radiators are characterized by their vertical flow of coolant from the top tank down through the core to the bottom tank. Question 9: An overflow tank is used to: A) Increase the overall coolant capacity of the system. B) Filter impurities from the engine coolant. C) Catch coolant that is expelled by the radiator cap when the coolant heats up and expands. D) Provide a резервуар for adding coolant to the system. Rationale: The correct answer is C. The overflow tank (or coolant recovery tank) serves to collect coolant that expands and is forced out of the radiator as the engine heats up. As the engine cools, this coolant is drawn back into the radiator, preventing air pockets and maintaining a full cooling system. Question 10: The outward force that is exerted on a rotating body is known as: A) Centripetal force. B) Inertia.
C) Centrifugal force. D) Torque. Rationale: The correct answer is C. Centrifugal force is the apparent outward force experienced by an object moving in a circular path. It's the reaction to the centripetal force that is actually pulling the object towards the center of rotation. Question 11: Engine heat is transferred from _____ components to _____ ones. A) Cooler; hotter B) Larger; smaller C) Hotter; cooler D) Faster moving; slower moving Rationale: The correct answer is C. Heat always naturally flows from areas of higher temperature to areas of lower temperature, following the laws of thermodynamics. Therefore, heat is transferred from the hotter engine components to the cooler coolant and surrounding air. Question 12: Coolant absorbs heat from the engine by ________. A) Radiation B) Conduction C) Convection D) Insulation Rationale: The correct answer is C. Convection is the transfer of heat through the movement of fluids (liquids or gases). As the coolant circulates through the engine, it absorbs heat from the engine components through conduction, and then this heated coolant moves away, allowing cooler coolant to take its place, thus transferring heat away from the engine by convection. Question 13: The _____ consists of many air doors, which are plastic or metal flaps that seal off parts of the air box to control airflow in the vehicle's heating and cooling system.
Technician A states that before starting a repair or service task on the cooling system, one should allow sufficient time for the system to cool adequately before opening the pressurized system. Technician B states that the presence of coolant does not impact the replacement of the thermostat. Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: The correct answer is A. Technician A is correct because opening a pressurized cooling system while it is hot can result in 喷出 hot coolant and steam, causing serious burns. Technician B is incorrect; the presence of coolant necessitates draining at least a portion of the system before the thermostat housing can be opened to replace the thermostat, to avoid spills and ensure a clean working environment. Question 17: Performing a _______ can help determine whether to perform a radiator repair or to buy a new radiator. A) Pressure test B) Flow test C) Cost analysis D) Visual inspection Rationale: The correct answer is C. A cost analysis involves comparing the estimated cost of repairing the existing radiator (including parts and labor) with the cost of purchasing and installing a new radiator. This comparison helps make an informed decision based on economic factors. Question 18: Which of the following statements is true with respect to removing and replacing a thermostat? A) It is not necessary to drain any coolant before removing the thermostat.
B) Drain at least 50% of the coolant to avoid spills when the thermostat housing is opened. C) The thermostat housing can be opened immediately after the engine is turned off. D) The new thermostat should be installed without any sealant or gasket. Rationale: The correct answer is B. Draining a significant portion of the coolant (at least 50%) is essential before opening the thermostat housing to prevent a large spill of coolant. Opening the system while hot (C) is dangerous. A new thermostat typically requires a new gasket or sealant (D) to ensure a proper seal. Question 19: Simple distillation of crude oil was the only commercial refinement process until the early ______, and the bulk of commercial oil products on the market are still produced by this process, such as conventional engine oils. A) 1890s B) 1930s C) 1970s D) 2000s Rationale: The correct answer is C. While distillation is a primary refining process, more advanced techniques were developed over time. However, simple distillation remained the dominant commercial method until the early 1970s, and it still forms the basis for producing many conventional petroleum products, including engine oils. Question 20: A crescent oil pump is typically mounted to ______. A) The rear of the engine block. B) The top of the cylinder head. C) The front of the engine block. D) Inside the oil pan. Rationale: The correct answer is C. Crescent oil pumps are commonly mounted to the front of the engine block, often driven directly by the crankshaft or camshaft, allowing for efficient oil pickup and circulation throughout the engine.
D) Neither A nor B Rationale: Technician B is correct. When removing rod caps, positioning the piston at bottom dead center (BDC) provides the most accessible position for the connecting rod bolts and cap. Question 24: In an L-head (flat head) engine design, where are the valves located? A) In the block, off to one side of the cylinder. B) In the cylinder head, directly above the cylinder. C) In the piston crown. D) Integrated into the crankshaft. Rationale: In an L-head (flat head) engine design, the valves are located in the block, off to one side of the cylinder (A). This design is less common in modern engines. Question 25: Choose the correct statement: A) Overhead cam engine is used to simplify the valve train. B) Pushrod engines are inherently more complex than overhead cam engines. C) Overhead valve engines always have their camshaft in the cylinder head. D) DOHC stands for Dual Overhead Crankshaft. Rationale: Overhead cam engines are designed to simplify the valve train by eliminating pushrods and often rocker arms, leading to fewer moving parts between the camshaft and the valves. Question 26: Technician A says the ridge at the top of the cylinder is too big if after the carbon has been scraped off it catches a fingernail. Technician B says that if the ridge is significant, and you plan to reuse the pistons, you will need to remove the ridge with a tool called a ridge reamer. Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B
Rationale: Both Technician A and Technician B are correct. A ridge that catches a fingernail indicates significant wear, and a ridge reamer is the correct tool to remove it before piston removal to prevent damage to the piston or rings. Question 27: When removing a main bearing cap, the lower half of the main bearing inserts may come away with the cap as you remove it, or they may stick to the ________ journal. A) Connecting rod B) Camshaft C) Crankshaft D) Piston Rationale: The lower half of the main bearing inserts may stick to the crankshaft journal (C). Question 28: Which of the following is LEAST likely to be found in the oil pan of an engine being disassembled? A) Metal shavings B) Sludge C) Core plugs D) Gasket material remnants Rationale: Core plugs (C) are typically found in the engine block or cylinder head, sealing water jackets, not in the oil pan during a normal engine disassembly. Metal shavings, sludge, and gasket material remnants are common findings. Question 29: All of the following damages are to be inspected in a timing belt, except: A) Cracks B) Missing teeth C) Fraying D) Swaying Rationale: Swaying (D) is not a typical type of damage inspected in a timing belt. Cracks, missing teeth, and fraying are all indications of a worn or damaged timing belt that requires replacement.
A) Welding is done on castings that have enough material to sustain the weld and survive the experience. B) Crack welding is suitable for all types of engine cracks. C) Welding always results in a perfectly invisible repair. D) Welding is a cold repair process that minimizes distortion. Rationale: Welding is done on castings that have enough material to sustain the weld and survive the experience (A). Welding introduces significant heat, so the casting must be able to handle the thermal stress without further cracking or warping. Question 34: Technician A says that the machinist picks the method that should be used to check out a set of cylinder heads that were dropped off for inspection. Technician B says that the technician tells the machinist which method to use to check a set of cylinder heads. Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: Technician A is correct. The machinist, with their specialized knowledge and equipment, is responsible for determining the most appropriate method to inspect and check cylinder heads for defects. Question 35: Engine machining is performed any time the ________ of an engine component must be adjusted by adding or removing material. A) Color B) Weight C) Tolerances D) Finish Rationale: Engine machining is performed any time the tolerances (C) of an engine component must be adjusted by adding or removing material. This ensures that parts fit and operate within specified clearances.
Question 36: Tech A states that a baked gasket must be carefully scraped from the surface without causing scratches on the sealing surface. Tech B states that metal gasket scrapers must not be used when working with cast iron. Who is correct? A) Tech A B) Tech B C) Both A and B D) Neither A nor B Rationale: Tech A is correct. Care must be taken to avoid scratching sealing surfaces when removing baked gaskets. Tech B is incorrect; metal gasket scrapers can be used on cast iron, but caution is always needed to prevent damage. Question 37: Most manufacturers recommend the use of ________ to scrape aluminum surfaces. A) Steel wire brush B) Metal putty knife C) Roloc™ bristle disc D) Sandpaper Rationale: Most manufacturers recommend the use of a Roloc™ bristle disc (C) or similar non- abrasive tools to scrape aluminum surfaces, as aluminum is softer and more prone to scratching than cast iron. Question 38: Technician A says that some engines do not use cover gaskets as they are sealed using RTV. Technician B states the use of rubber style of gaskets on newer vehicles is becoming common place as they do not leak as much as paper gaskets. Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: Both Technician A and Technician B are correct. Many modern engines use Room Temperature Vulcanizing (RTV) sealant in place of traditional gaskets, and rubber gaskets are indeed common in newer vehicles due to their superior sealing properties compared to paper gaskets.
Rationale: Both A and B are correct. The small end of the connecting rod, attached to the piston, moves linearly (reciprocates). The big end, attached to the crankshaft, primarily moves in a circular (rotational) motion. Question 42: Technician A says that a technician can do his or her own balancing with a small scale. Technician B states that normal engines do not need to be balanced at all. Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: Neither A nor B is correct. Proper engine balancing requires specialized equipment beyond a small scale to accurately measure and adjust the balance of components. While some production engines have acceptable balance from the factory, precise balancing is crucial for high-performance or rebuilt engines to reduce vibration and extend component life. Question 43: __________ an engine ensures that there is a consistent combustion pressure on the crankshaft between cylinders. A) Balancing B) Blueprinting C) Honing D) Machining Rationale: Blueprinting (B) an engine ensures that there is a consistent combustion pressure on the crankshaft between cylinders. This involves meticulously measuring, correcting, and assembling engine components to exact specifications, often tighter than factory tolerances. Question 44: Technician A says that a crankshaft that is internally balanced is measured with a harmonic balancer or a flywheel/flex plate installed. Technician B says that an externally balanced crankshaft is measured without a harmonic balancer or a flywheel/flex plate installed. Who is correct? A) Technician A B) Technician B C) Both A and B
D) Neither A nor B Rationale: Neither technician is correct. An internally balanced crankshaft is balanced without the harmonic balancer or flywheel/flex plate installed, as its balance is achieved solely within the crankshaft itself. An externally balanced crankshaft relies on counterweights on the harmonic balancer and/or flywheel/flex plate for its balance, so it must be measured with these components installed. Question 45: Technician A says that crankshafts are balanced by either drilling out weight or adding more weight. Technician B says that crankshafts are only balanced in the rotational plane. Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: Technician A is correct. Crankshafts are balanced by either removing material (drilling) or adding material (e.g., heavy metal slugs) to achieve proper balance. Technician B is incorrect because crankshafts are balanced in both the rotational and reciprocating planes to minimize vibration. Question 46: Any threaded plugs, such as the rear oil gallery plugs, should be coated with a sealer, preferably a liquid ________ or a similar nonhardening sealer. A) Super glue B) RTV sealant C) Teflon D) Anaerobic sealant Rationale: Any threaded plugs, such as the rear oil gallery plugs, should be coated with a sealer, preferably a liquid Teflon (C) or a similar nonhardening sealer. Teflon sealants are good for sealing pipe threads and resisting oil. Question 47: A Welch plug is a: A) Type of threaded fastener used to seal engine blocks. B) Diagnostic tool for checking engine compression.
D) Dial indicator Rationale: Plastigage (C) should be used to check the bearing clearance with the crankshaft installed. Plastigage is a thin, plastic thread that flattens when the bearing cap is torqued, and its flattened width indicates the clearance. Question 51: Two technicians were discussing the installation of various plugs into the heads and block. Technician A said "When installing gallery plugs and soft plugs, you should apply the appropriate sealer to both." Technician B says "always install any plugs clean and dry." Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: Technician A is correct. Both gallery plugs (which often seal oil or coolant passages) and soft plugs (or freeze plugs, which seal water jackets) typically require an appropriate sealer to prevent leaks. Installing them clean and dry would likely result in leaks. Question 52: Technician A says that main and rod bearings are glued in place with special bearing cement. Technician B says that main and rod bearings are held in place by a precise amount of "bearing crush." Who is correct? A) Technician A B) Technician B C) Both A and B D) Neither A nor B Rationale: Technician B is correct. Main and rod bearings are held in place by "bearing crush," which is a slight interference fit that ensures the bearing shells are tightly seated in their bores, preventing rotation. They are not glued. Question 53: All of the following statements with respect to thrust bearing are true, except: A) Thrust bearings control crankshaft end play. B) They are typically located on a specific main bearing journal. C) Usually the thrust bearings are located in the foremost bearing.
D) If thrust bearing clearance is excessive, it can lead to crankshaft walk. Rationale: The statement "Usually the thrust bearings are located in the foremost bearing" (C) is incorrect. Thrust bearings are typically located on a specific main bearing journal, but it is often the center main bearing or another designated main bearing, not necessarily the foremost one. Question 54: Choose the correct statement with respect to reinstalling the engine in vehicles equipped with automatic transmissions: A) It is not necessary to change the front transmission seal if it appears to be in good condition. B) It is a good idea to consider changing the front transmission seal while the torque converter is removed. C) The torque converter should be filled with new transmission fluid before installation. D) The transmission fluid should be drained completely before engine reinstallation. Rationale: It is a good idea to consider changing the front transmission seal while the torque converter is removed (B). This is a preventative measure, as accessing this seal later would require removing the transmission again, which is a significant job. Question 55: If a vacuum fill method of filling the cooling system was used, the cooling system will ________. A) Have air pockets. B) Be partially filled. C) Be full. D) Require bleeding. Rationale: If a vacuum fill method of filling the cooling system was used, the cooling system will be full (C). The vacuum method pulls all air out, ensuring a complete fill. Question 56: After the engine has been given a proper break in, the oil level is inspected and the level is found to be higher and milky in appearance. What is this an indication of? A) Overfilling of oil. B) Possible internal coolant leak. C) Excessive blow-by. D) Condensation from cold weather.
