Valve Gear

The camshaft obtains the drive from the crankshaft through the timing gears. The cams acting upon the tappets, pushrods and rocker arms cause the valves to open in a strict sequence.

Connecting rod

Fig. Connecting rod, 5Д2, 5Д2-1, 5112, 8П2 and 10П2 diesel engines: 1 — camshaft timing gear; 2 — ratchet wheel; 3 — key; 4 — tab washer; 5 — tappet; 6 — exhaust valve pushrod; 7 — compression release handle; 8 — compression release spindle; 9 — disc of compression release spindle; 10 — inlet valve pushrod; 11 – spring; 12— housing; 13 — spindle; 14 — driven bevel gear; 15 — drive bevel gear; 16 — cover plate; 17 — tachometer drive; 18— nut; 19 — bearing housing; 20 — arm; 21 — camshaft; 22 — ball bearing; 23 — spacer ring

Camshaft 21 rests in two rolling-contact bearings and is provided with six cams. Cams 1 and 6 control the operation of the exhaust valves, cams 3 and 4 are linked up with the inlet valves and cams 2 and 5, which are of somewhat narrower configuration, operate the fuel injection pumps; one of the last-named cams also imparts motion to the fuel feed pump.

Camshaft, ДС8, ДС12, П12, П21 and П22 diesel engines

Fig. Camshaft, ДС8, ДС12, П12, П21 and П22 diesel engines: 1 — camshaft; 2 — tappet; 3 — pushrod; 4 — compression release spindle; 5 — disc of compression release spindle

Camshaft 1 receives support from two bearings mounted in the block and is provided with four cams. While cams 1 and 4 control the exhaust valves, cams 2 and 3 actuate the inlet valves.

Diesel engine 5Д4 (transverse section)

Fig. Diesel engine 5Д4 (transverse section): 1 — crankcase-and-cylinder block; 2 — breather body; 3 — oil level gauge; 4 – camshaft; 5 — fuel feed pump; 6 — tappet; 7 — fuel injection pump; 8 – cover plale; 9 — pushrod; 10 –  asbestos steel gasket; 11 — heater plug; 12 — cylinder head; 13 — injector; 14 — lifting fixture; 15 — air cleaner; 16 — exhaust manifold; 17 – cylinder liner; 18 — piston; 19 – connecting rod; 20 — packing ring; 21 – starter motor; 22 — manhole cover; 23 — cooler

Diesel engine 5П4 (transverse section)

Fig. Diesel engine 5П4 (transverse section): 1 — cylinder-and-crankcase block; 2 — breather body; 3 — oil level gauge; 4 — camshaft; 5 — fuel feed pump; 6 — tappet; 7 — fuel injection pump; 8 — cover plate; 9 — pushrod; 10 — asbestos steel gasket; 11 — heater plug; 12 — cylinder head; 13 — injeclor; 14 — lifting fixture; 15 — air cleaner; 16 — exhaust manifold; 17 — cylinder liner; 18 — piston; 19 — connecting rod; 20 — packing ring; 21 — slarter motor; 22 — manhole cover; 23 — stirrup

On the 4ч diesel engines, camshaft 4 is supported in the block by three bearings and features eight cams, those shown at 1, 4, 5 and 8 being the exhaust valve cams and those shown at 2, 3, 6 and 7 being the inlet valve cams.

Diesel engines 5Д6, 8Д6, 10Д6 (transverse section)

Fig. Diesel engines 5Д6, 8Д6, 10Д6 (transverse section): 1 — cylinder-and-crankcase block; 2 — breather body; 3 — oil level gauge; 4 — camshaft; 5 — fuel feed pump; 6 — tappet; 7 — fuel injection pump; 5 — cover plate; 9 — pushrod; 10 — asbestos steel gasket; 11 — heater plug; 12 — cylinder head; 13 — injector; 14 — lifting fixture; 13 — air cleaner; 16 — exhaust manifold; 17 — cylinder liner; 18 — piston; 19 — connecting rod; 20 — packing ring; 21 — starter motor; 22 — manhole cover; 23 — cooler

On the 6ч diesel engines, camshaft 4 rests in four hearings and has twelve cams. Cams 1, 4, 5, 8, 9 and 12 actuate the exhaust valves and the rest of the cams impart motion to the inlet valves.

Cylinder head

Fig. Cylinder head: 1 — cylinder head; 2 — rocker arm bracket; 3 — adjusting screw: 4 — rocker arm assembly; 5 — rocker arm fulcrum pin; 6, 20 — nut; 7 — stud; 8 — valve cover; 9 — valve cotter; 10 — valve spring retainer; 11 — safety ring; 12 — valve spring; 13, 21 — gasket; 14 — valve guide; 15 — exhaust valve; 16 — inlet valve; 17 — pin; 18 — turbulence chamber insert; 19 — heater plug; 22 — tube; I — order of cylinder head nuts tensioning

Inlet valve 16 and exhaust valve 15 each feature a flat disc with mitered seat (angle 45°). The diameter of the inlet valve disc is somewhat greater than that of the exhaust valve disc. The valve stem has grooves at its ends serving to accommodate cotter 9 and safety ring 11. Each valve is returned into its seat due to the action of spring 12.

Each valve rocker arm 4 is provided with an adjusting screw 3 and hinges about fulcrum pin 5.

Diesel engine 5Д4 (longitudinal section)

Fig. Diesel engine 5Д4 (longitudinal section): 24 — strainer; 25 — flywheel casing; 26 — flywheel gear ring; 27 — flywheel; 28 — pin; 29 — crankshaft; 30 — flywheel bolt; 31 — flywheel pin; 32 — main bearing shell; 33 — oil filter; 34 — cylinder head cover; 35 — expansion tank; 36 — speed governor; 37 — mounting plate; 38 — jacket water pump; 39 — outside water pump; 40 — crankpin bearing shell; 41 — sump; 42 — split rings

Spindle 8 of the compression release gear is fitted in the transverse partitions of the block and is provided with handle 7 which has a detent serving to lock the gear either in the engaged or in thereleased positions. When the handle is being turned, flats on the spindle cause exhaust valves 15 to become unseated thought dises 9 and push rods 6.

Timing gears, 5Д2, 5Д2-1, 5П2, 8П2 and 10П2 diesel engines

Fig. Timing gears, 5Д2, 5Д2-1, 5П2, 8П2 and 10П2 diesel engines: 1 — oil pump drive gear; 2 — camshaft timing gear; 3 — exhaust valve cam of first cylinder; 4 — governor gear; 5 — crankshaft timing gear; 6 — water pump drive gear; I – timing marks

Timing gears, ДС8, ДС12, G12, П21, П22 and 4ч diesel engines

Fig. Timing gears, ДС8, ДС12, G12, П21, П22 and 4ч diesel engines: 1 — idler gear of water pump drive; 2 — oil pump drive gear; 3, 4 — camshaft timing gears; 5 — fuel injection pump drive gear; 6 — water pump gear; 7 — crankshaft timing gear; 8 — outside water pump drive gear; I — timing marks

Timing gears, 6ч diesel engines

Fig. Timing gears, 6ч diesel engines: 1 — idler gear of water pump drive; 2 — oil pump drive gear; 3, 4 – camshaft timing gears; 5 — fuel injection pump drive gear; 6 — water pump gear; 7 – generator gear; 8, 9 — generator drive gears; 10 — intermediate generator drive gear; 11 – crankshaft timing gear; 12 — outside water pump drive gear; I — timing marks

Timing gears, of the angular type and in steel, serve to transmit rotary motion from the crankshaft to the camshaft and other accessories of the engine. The timing gears are fitted with due regard to the timing marks provided thereon: make sure the mark between two teeth on one of the gears registers with the mark at the top of a tooth on the other gear.

On the 5Д2, 5Д2-1, 5П2, 8П2, and 10П2 diesel engines, tachometer drive 17 is provided at the flywheel end of the block and is linked up to the camshaft through arm 20 so as to receive rotation. Some of the 2ч diesel engines are marketed without tachometers, the tachometer drive hole being blanked off in this case.