In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low-alloy steels because _____________./intake valves are less affected to the corrosive action of exhaust gases The opening of an exhaust valve on a modern, large, low- speed, main propulsion diesel engine, may be actuated by _____________./hydraulic "push rods" The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by _____________./compressed air pressure If the intake, or exhaust valve stem clearance is found to be excessive, in addition to too little movement of the rocker arms, you should check for _____________./collapsed hydraulic valve lifters A burned exhaust valve may be detected by a higher than normal ____________./exhaust temperature from a particular cylinder Which of the listed conditions will occur if a diesel engine exhaust valve is leaking?/All of the above In a diesel engine, a leaking exhaust valve can cause _____________./misfiring Exhaust valve grooving and corrosion is caused by certain components of residual fuel oil. These components are sodium, sulfur, and _____________./vanadium The easiest way to locate a defective diesel engine exhaust valves is by _____________./comparing exhaust pyrometer readings Increasing the exhaust valve tappet clearance of a diesel engine will result in the exhaust valve opening __________./later and closing earlier Diesel engine exhaust valve springs are under compression when they are __________./in any position A diesel engine exhaust valve spring is under compression when _____________./all of the above The intake and exhaust valves used in a diesel engine are returned to their seats by _____________./spring force In which of the scavenging methods listed will the exhaust valve be located in the cylinder head?/Uniflow The purpose of an interference angle in a diesel engine exhaust valve is to ________. I. work in conjunction with valve rotators to rotate the valve II. break up seat deposits/II only The purpose of an interference angle in a diesel engine exhaust valve is to ________. I. break up seat deposits II. work in conjunction with valve rotators to rotate the valve/I only The exhaust valve opens before bottom dead center in a four stroke engine to___________. I. allow for blow down II. reduce pumping losses/both I and II The purpose of an interference angle in a diesel engine exhaust valve is to ________. I. seat the valve quickly II. break up seat deposits/both I and II The purpose of an interference angle in a diesel engine exhaust valve is to ________. I. work in conjunction with valve rotators to rotate the valve II. seat the valve quickly/II only In a diesel engine, exhaust valves open before the intake ports are uncovered to ___________. I. reduce pumping losses II. reduce back pressure/both I and II A substance found in residual fuels which tends to cause exhaust valve corrosion and grooving, is ____________./vanadium During diesel engine warm-up, which type of valve lash adjuster listed allows for the change in length of the exhaust valves?/Hydraulic Which of the listed design features is found in an exhaust valve and NOT in an intake valve?/Hard alloy steel construction Many diesel engine exhaust valves are being constructed with hollow stems filled with sodium in order to _____________./assist in dissipating heat due to the extreme operating temperatures A built-up exhaust valve is one in which _____________./the stem and heads are made of different material The size of the exhaust valve opening is ____________./most critical in a two-stroke/cycle diesel engine Exhaust valve openings in a diesel engine cylinder head are made as large as practical to _____________./reduce the pumping loss associated with scavenging The satisfactory operation of diesel engine exhaust valves usually depends on ______________./correct timing and proper seating Decreasing the exhaust valve clearance of a diesel engine will cause the exhaust valve to open ______________./earlier and remain open longer Multiple concentric valve springs are often used with diesel engine valves to ____________./operate the valve gear where a larger force is normally required, but space limitations restrict the use of a single large spring If the valve tappets in a diesel engine are set at greater clearances than those specified by the engine manufacturer, those valves will _____________./open late and close early Increasing the valve clearance between a valve stem and rocker arm, will result in the valve _____________./staying open for a shorter period of time Which of the listed items should be secured before performing any maintenance on a solenoid operated air start valve?/Electric power An important design characteristic of an explosion relief valve for a diesel engine is the ability to _________./close quickly in order to prevent an inrush of air Which statement regarding the arrangement and location of explosion relief valves used on an internal combustion engines is true_____________?/Minimizing the danger from emission of flame is a key consideration Collapsed hydraulic valve lifters in a diesel engine will result in ____________./excessive valve clearance At what pressure should a cylinder relief valve of an internal combustion engine be set to relieve?/The device should be set to relieve at a pressure not more than 40 percent in excess of the maximum firing pressure. The diesel engine valve subjected to most severe conditions of service is the ____________./cylinder exhaust valve When the cold tappet clearance is less than that specified by the engine manufacturer, the diesel engine valves will _____________./open earlier than normal In diesel engines, hydraulic valve lifters are used to ____________./reduce valve gear pounding Valve lash, or clearance refers to the _____________./clearance between the top of the valve stem and the rocker arm What is the purpose of a hydraulic valve lash adjuster?/Allows for constant contact between the valve stem and the rocker arm regardless of whether the engine is cold or warm. Diesel engine valve springs function to _____________./close the valves Valve cages are used on some large diesel engines to _____________./facilitate valve removal for servicing During warm-up the expansion of valve stems due to engine heat, is allowed for by the _____________./valve lash In a diesel engine, the spring force required for proper valve operation is determined by _____________./cam contour According to Coast Guard regulations, isolation valves used in keel cooler installations are permitted to be constructed of ____________./bronze If a single cylinder relief valve on a diesel engine lifts frequently while the engine is running, the cause may be an _____________./incorrectly adjusted fuel injector Diesel engine air start valve timing is controlled by _____________./individual cams and valve gear If there is a "clicking" sound in the valve compartment of a diesel engine, the cause may be _____________./excessive valve lash Excessively worn, or polished ends on a diesel engine valve spring, indicate ________________./spring surge Excessive valve clearance will cause a valve to open _____________./late and close early The valve stem expansion associated with engine warm-up is allowed for by the ____________./valve lash adjusters Diesel engine air start system check valves are opened by _____________./starting air pressure Excessive valve lash in an auxiliary diesel engine will cause the valves to open _____________./later and close sooner If the valve lash on a diesel engine is set improperly, which of the following statements represents the most serious problem that can develop?/Too little lash may prevent the valves from seating properly. If you increase the clearance between a valve stem and rocker arm, which of the listed conditions will occur?/Valve will open later. Reducing the clearance between a valve stem and rocker arm will result in the valve _____________./having a longer duration of opening If you were inspecting the valve springs on an auxiliary diesel engine, your best indication of impending spring failure would be _____________./cracks in the surface of the spring If the relief valve on a diesel engine cylinder lifts, the cause could be due to _____________./liquid in the cylinder Which of the listed items should be secured before performing any maintenance on a solenoid operated air start valve?/Electric power and starting air Bouncing of the valve gear in a diesel engine can be caused by _____________./spring surge Spring surge in diesel engine valve springs can result in _____________./bouncing of the valve gear If a clicking sound is being produced from within the valve compartment of a diesel engine, the cause may be __________./all of the above The force exerted by a valve spring to close the diesel engine valves, is proportional to _____________./spring compression | |
