remove the piston pin, the connecting rod should be supported  so that it does not have to take the shock of the blows. If this  is not done, the rod may be damaged. After the removal of a cylinder and piston, the connecting  rod must be supported to prevent damage to the rod and  crankcase. This can be done by supporting each connecting  rod with the removed cylinder base oil seal ring looped  around the rod and cylinder base studs. Using a wire brush, clean the studs or cap-screws and  examine them for cracks, damaged threads, or any other  visible defects. If one cap-screw is found loose or broken  at the time of cylinder removal, all the cap-screws for the  cylinder should be discarded, since the remaining cap-screws  may have been seriously weakened. A cylinder hold down  stud failure places the adjacent studs under a greater operating  pressure, and they are likely to be stretched beyond their  elastic limit. The engine manufacturer’s instruction must be  followed for the number of studs that have to be replaced  after a stud failure. When removing a broken stud, take proper  precautions to prevent metal chips from entering the engine  crankcase section. In all cases, both faces of the washers and  the seating faces of stud nuts or cap-screws must be cleaned  and any roughness or burrs removed. See that all preservative oil accumulation on the cylinder and  piston assembly is washed off with solvent and thoroughly  dried with compressed air. Install the piston and ring  assembly on the connecting rod. Be sure that the piston  faces in the right direction. The piston number stamped on  the bottom of the piston head should face toward the front  of the engine. Lubricate the piston pin before inserting it. It  should fit with a push fit. If a drift must be used, follow the  same precaution that was taken during pin removal. Oil the exterior of the piston assembly generously, forcing  oil around the piston rings and in the space between the  rings and grooves. Stagger the ring gaps around the piston  and check to see that rings are in the correct grooves, and  whether they are positioned correctly, as some are used as  oil scrapers, others as pumper rings. The number, type, and  arrangement of the compression and oil-control rings vary  with the make and model of engine. Perform any and all visual, structural, and dimensional  inspection checks before installing the cylinder. Check the  flange to see that the mating surface is smooth and clean.  Coat the inside of the cylinder barrel generously with oil. Be  sure that the cylinder oil-seal ring is in place and that only  one seal ring is used. Furthermore, rotating the crankshaft with the push rod  resting on the edge of the tappet may bend the push rod.  After installing the push rods and rocker arms, set the valve  clearance. Before installing the rocker-box covers, lubricate  the rocker arm bearings and valve stems. Check the rocker- Reinstall the push rods, push rod housings, rocker arms, barrel  deflectors, intake pipes, ignition harness lead clamps and  brackets, fuel injection line clamps and fuel injection nozzles  (if removed), exhaust stack, cylinder head deflectors, and  spark plugs. Remember that the push rods must be installed  in their original locations and must not be turned end to end.  Make sure that the push rod ball end seats properly in the  tappet. If it rests on the edge or shoulder of the tappet during  valve clearance adjustment and later drops into place, valve  clearance is off.  Install the remaining nuts or cap-screws and tighten them  until they are snug. The hold down nuts, or cap-screws, must  now be torqued to the value specified in the table of torque  values in the engine manufacturer’s service or overhaul  manual. Apply the torque with a slow, steady motion until  the prescribed value is reached. Hold the tension on the  wrench for a sufficient length of time to ensure that the nut  or cap-screw tightens no more at the prescribed torque value.  In many cases, additional turning of the cap-screw, or nut,  as much as one-quarter turn can be done by maintaining  the prescribed torque on the nut for a short period of time.  After the stud nuts, or cap-screws, have been torqued to the  prescribed value, safety them in the manner recommended  in the engine manufacturer’s service manual. After the cylinder has slipped on the piston, so that all piston  rings are in the cylinder bore, remove the ring compressor  and the connecting rod guide. Then, slide the cylinder into  place on the mounting pad. If cap-screws are used, rotate the  cylinder to align the holes. While still supporting the cylinder,  install two cap-screws or stud nuts 180° apart. Using a ring compressor, compress the rings to a diameter  equal to that of the piston. With the piston at TDC, start the  cylinder assembly down over the piston, making certain  that the cylinder and piston plane remain the same. Ease  the cylinder over the piston with a straight, even movement  that moves the ring compressor as the cylinder slips on. Do  not rock the cylinder while slipping it on the piston, since  any rocking is apt to release a piston ring or a part of a ring  from the ring compressor prior to the ring’s entrance into the  cylinder bore. A ring released in this manner expands and  prevents the piston from entering the cylinder. Any attempt  to force the cylinder onto the piston is apt to cause cracking  or chipping of the ring or damage to the ring lands. Cylinder Installation 10-43