TM 10-3930-653-14&P (2)  INSTALLING PISTON RINGS (1)  Make sure that top, second, and oil rings are placed in proper positions and are not interchanged. Reassemble  oil  ring,  second  ring,  and  top  ring  in  that order. (2)  Install rings with piston ring notch facing up. Fig. 4-77.  Correct Piston Ring Position on Piston. Fig. 4-78.  Section View of Piston Rings. 4-2-5-3.  ASSEMBLING OF ENGINE (1) INSTALLING VALVES AND VALVE SPRINGS Use   Valve   Lifter   to   install   intake   and   exhaust   valves, valve  springs,  valve  spring  retainers,  valve  collets  and rubber rings to cylinder head in the order listed Note: a. Do not interchange valves between cylinders,    for    their    sliding    or    seating surfaces   have   undergone   wearing-in   or have  been  lapped  at  assembly,  forming specific contact with their mating parts. b. Check to be sure that valves are properly seated   on   valve   seats   without   foreign particles stuck inbetween. Fig. 4-79.  Installing Valve Springs. 4-43