© 0883 Layout and Description of Engine Section: 2 Page: 2-0-01 Engine: S/BVM 628 2 Layout and Description of Engine 2.1 01 Cylinder Head The Head iß held down on the crankcase through 4 hydraulically tightened studs. Fitted in the head are 2 inlet valves, 2 exhaust valves, one fuel injector, a starting valve, an indicator valve and, if required, a relief valve. The exhaust valves are equipped with rotators, the inlet valves with a seat lubrication to reduce wear. In fact, oil is injected in a metered amount into the charge air, so this seat lubrication requires no servicing. Injector and inlet/exhaust valves plus drive are protected by a rocker chamber cover.
Coolant transfer from crankcase to head is made through plugged pipes within the head contour. 2.2 02 Crankshaft System The drop-forged crankshaft is fitted in the crankcase in underslung arrangement. Main journals and crankpins are hardened and carried in complex-metal bearing shells. As required by the rated engine spee, the shaft is fitted with balance weights to reduce mass forces. The bearing caps are secured to the crankshaft by 2 vertical and 2 horizontal bolts, the former ones being tightened jointly by a hydraulic tool. The flywheel is flanged to the shaft‘s driving end, the flange being fitted on the shaft by hydraulic shrinkage.
Power for secundary drives can be taken off from the shaft‘s free end. The drop-forged connecting rod big end is split in straight (horizontal) arrangement, while the small end is of the stepped type. The two-piece pistons are fitted with 3 compression rings and one oil control ring. The former rings are located in the steel top, the oil ring in the piston skirt above the full-float piston pin. 2.3 03 Engine Frame The crankcase is a single-piece casting. Large doors permit easy access to all motion parts. Some doors may optionally be provided with relief valves safeguarding the engine in the case of crankcase of explosions.
The standard deep ”wet-type” oil sump represents the engine‘s lube oil reservoir, from which oil is forced into the lubricating circuit by a special delivery pump. Where high or low-level tanks are utilized for oil reservoir, use is made of a flat ”dry-type” sump with connections for an oil drain (to the low-level tank) or a special suction pump (to the high-level tank) respectively. The cylinder liner is located in the crankcase at top and bottom. The liner flange is seated on a highly waer-resistant ring pressed into the crankcase. The water jackets are sealed by one ”watercooled” Viton 0-seals at the bottom. The head/liner gasket is a steel ring.