UTI Auto/Diesel 101 End of Course Exam Questions And Answers

UTI Auto/Diesel 101 End of Course Exam Questions And Answers What part of the bearing is the softest? What is this part's job? How does it accomplish this? - ANSWER -The bearing lining is the softest part of the bearing. This is so that the bearing has embeddability, which allows it to absorb debris, so that the bearing doesn't loose clearance. When would a technician use a rigid spring hone? A flex ball hone? - ANSWER -If the cylinder wall has some light scoring the rigid spring hone could refinish the cylinder wall. The flex ball hone is used to crosshatch the cylinder wall. What is a crosshatch pattern? What approximate degree angle is best? Why is this angle best? - ANSWER -Crosshatch along the cylinder walls allows oil to stick to the cylinders allowing the piston rings to create a seal in the cylinder. 20-60 degrees works best; less than 20 allows oil to run too quick and more than 60 creates a thick layer. Define friction bearing. Define anti-friction bearing. - ANSWER -A friction bearing uses oil passages to create clearance with oil pressure; an anti-friction bearing uses steel balls, rollers, or pins to allow movement between two parts. Describe the procedure of disassembling an engine to ensure proper reassembly. - ANSWER -Mark and label parts for orientation and order. What type of bearing is used primarily in light load high speed conditions (alternators, water pumps, etc...)? - ANSWER -Anti-friction bearings Define hydrodynamic wedge of oil - hydrodynamic oil film. - ANSWER -A hydrodynamic wedge is formed under a normal bearing journal. Oil particles stick to the surface of the journal and to the surface of the bearing creating layers. The oil in between flows pushing against the two layers. What is the procedure for installing any bearing into the block? - ANSWER Make sure to clean and dry both the bearing (on both sides) and the journal surface. What is the procedure to torque the crankshaft in the block? - ANSWER -Tap down the main caps with a plastic handle, start with the inside caps and work outwards. What is the procedure for installing connecting rod bearings? - ANSWER -Clean and dry both sides of the bearings and the connecting rod. Only lubricate the inside of the bearings that meet the journal. Where does the oil flow to when it leaves the oil pump? - ANSWER -To the engine block oil gallery. What does "a controlled oil leak" mean? When is oil pressure established in a block? - ANSWER -Controlled oil leak means that the oil finds it's way back to the oil pan in a controlled manner if all the components are working properly. Oil pressure should be instantaneous as soon as the engine is started. Where is plasti-gauge used in an engine? - ANSWER -Plasti-gague is used between the main journal and the bearing. Do not crank engine when using plasti gauge. What is the other procedure for checking oil clearance? Which is more precise? - ANSWER -The other procedure is by using a "T" gauge and a micrometer. This procedure is more precise. If a bearing has excessive oil clearance what happens to the pressure after it? - ANSWER -Oil pressure drops. What regulates how much oil the oil pump delivers to the engine? - ANSWER The oil pressure regulator. What is the difference between the oil pressure regulator (relief valve) & the oil filter by-pass valve? - ANSWER -The oil pressure relief valve is located on the oil pump and the oil filter by-pass valve is located on the oil filter housing. What does the fillet do for the crankshaft? - ANSWER -It is located where the journal meets the crankshaft counter weight and it provides structural support. What are the holes in the crankshaft counter weight for? - ANSWER -This is done at assembly and they are made to provide final assembly balancing. How is crankshaft end play measured? With what tools? Crankshaft runout? - ANSWER -End play is measure either with a dial indicator placed at the end of the crankshaft snout, or using a feeler gage between the thrust plate and the crankshaft journal sidewall. What should a technician inspect and measure a crankshaft for when it returns from the machine shop? - ANSWER -Run-out, end-play, journal OOR & taper. What are the possible functions of an auxiliary shaft? What might they operate? - ANSWER -It can serve as a counter balance to reduce vibrations and it can run components such as the oil pump or distributor. Where are ring lands located on pistons? - ANSWER -On the top portion of the piston walls. What direction and order are rings installed on pistons? Define stagger. - ANSWER -The piston rings will be marked for correct direction. Clamp the assembly in a vise; the oil ring first (expander, top rail, then bottom rail); the lower compression ring, second; the top compression ring, third. Use a ring extender to install rings and always stagger the end gaps. How does a technician measure ring end gap? What happens if the gap is too wide or narrow? - ANSWER -The piston ring is inserted into the cylinder it came from and leveled using the piston itself. A feeler gauge is inserted into the gap until the correct size is found. If the gap is too wide it will allow compression to leak, if the gap is too narrow it might score the cylinder walls or break the ring lands when the ring expands. Which piston shapes have an effect on compression ratio? What else affects it? - ANSWER -Dome, irregular, and wedge top pistons increase compression ratio while dish pistons lower compression ratio. When visually inspecting a piston how would you proceed with the following: scored skirt, broken ring lands, detonation damage? - ANSWER -Replace the piston in each of these cases. What do you measure when inspecting a piston? - ANSWER -OUT OF ROUND How is ring side clearance measured? - ANSWER -With a feeler gauge.