What is Tappet clearance? How to take tappet clearance? What will happen if Tappet clearance is less or more? How to know which unit piston is at TDC? Why concentric springs fitted for aux engine cylinder head? What is the material of inlet and exhaust valves, piston, liner, piston rings, bedplate, A-frame, tie rod, crankshaft, cylinder head, turbocharger? Explain lubrication of different parts (rocker arm, main bearings, camshaft drive, governor drive, rocker arm, camshaft) in 4 stroke. What is the function of roto cap or valve rotator and working of it? What are the disturbances which may occur with roto cap ? Explain exhaust valve working of your main engine with diagram. Explain terminologies related to exhaust valve system and use of all components of exhaust valve system. What is the function of Spring air? Explain the function and working of puncture valve. What all clearances need to be checked during the main engine exhaust valve overhaul? What are the Stresses Working on main engine during its operation? What is the function of Top bracing? What are the causes of fatigue failure? What is the function of chock? Why resin chocks preferred? What is tie rod and its function? Why pinching screws are provided? How bending moment of tie rods are reduced? How will you come to know if there is breakage in tie rod? What may be the reasons of its breakage? What is the purpose of holding down bolts?