Connecting Rod-Crank Mechanism

Diesel engines are fitted with steel crankshafts which are forged, heat-treated and accommodated in block recesses.

Crankshaft

Crankshaft 29 rests in the main bearings by means of its journals; in addition, thrust bearing 32 prevents the crankshaft from axial displacement. The bearings are splash-lubricated except for the crankpin bearings which are taken care of by the oil reaching them through oil passages due to the action of lubricating ring 41 which is fitted to the front end of the crankshaft with a slight clearance. Flywheel 27 is fitted to the tapered end of the crankshaft and held in place by key 28 and nut 30.

Diesel engines 5Д2, 5Д2-1 (longitudinal section)

Fig. Diesel engines 5Д2, 5Д2-1 (longitudinal section): 24 — strainer; 25 — flywheel casing; 26 — flywheel gear ring; 27 — flywheel; 28 — key; 29 – crankshaft; 30 — flywheel nut; 31 — flywheel pin; 32 — thrust bearing; 33 – tachometer transmitter; 34 — cylinder head cover; 35 — pump rack leverage; 36 — speed governor; 37 — mounting plate; 38 — jacket water pump; 39 — outside water pump; 40 – crankpin bearing sheel; 41 — lubricating ring

Diesel engines 5П2, 8П2, 10П2 (longitudinal section)

Fig. Diesel engines 5П2, 8П2, 10П2 (longitudinal section): 24 – strainer; 25 — flywheel casing; 26 — flywheel gear ring; 27 — flywheel; 28 — key; 29 — crankshaft; 30 — flywheel nut; 31 — flywheel pin; 32 — thrust bearing; 33 – stud; 34 – cylinder head cover; 35 — pump rack leverage; 36 – speed governor; 37 – mounting plate; 38 — pulley; 39 — jacket water pump; 40 — crankpin bearing shell; 41 — lubricating ring

On the 2ч, 4ч and 6ч engines, crankshaft 29 rests with its main journals in bearing shells 32 and is prevented from axial play by split rings 42. An oil gallery running all the way along the block provides a supply of oil which reaches the main bearings through passages and is hence fed to crankpin bearing shells 40.

Diesel engines ДС8, ДС12 (longitudinal section)

Fig. Diesel engines ДС8, ДС12 (longitudinal section): 22 — strainer; 23 — flywheel casing; 24 — flywheel gear ring; 25 — flywheel; 26 — flywheel pin; 27 — speed governor; 28 — oil filter; 29 — crankshaft; 30 — mounting plate; 31 — jacket water pump; 32 — outside water pump; 33 — crankpin bearing shell; 34 — sump; 36 — cylinder head cover

Diesel engines П12, П21, П22 (longitudinal section)

Fig. Diesel engines П12, П21, П22 (longitudinal section): 24 — strainer; 25 — flywheel casing; 26 — flywheel gear ring; 27 — flywheel; 28 — pin; 29 — crankshaft; 30 — flywheel bolt; 31 — bolt; 32 — main bearing shell; 33 — oil filter; 34 — cylinder head cover; 35 — thermostat; 36 — speed governor; 37 — mounting plate; 38 — pulley; 39 — jacket water pump; 40 – crankpin hearing shell; 41 — sump; 42 — split rings; I — applies io flangeless engines

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

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

Diesel engines 5Д6, 8Д6 (longitudinal section)

Fig. Diesel engines 5Д6, 8Д6 (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

The shells of both main and crankpin bearings are in an antifriction alloy backed by steel and are provided each with a locating projection. The bearing shells are interchangeable. The top shell of each main bearing is provided with a circumferential groove and is placed into the block while the lower shell dispenses with the groove and is accommodated in a stirrup.

Piston

Piston 1 is made of an aluminium alloy and accommodates three compression rings 2 and two oil control rings 5 in its grooves; the lowermost oil control ring is located below the bosses which have drillings fitted wherein in the piston pin. The oil accumulating in the oil control ring grooves is draining through radial holes in the piston.

Connecting rod-pislon assembly

Fig. Connecting rod-piston assembly: 1 — piston; 2 — compression ring; 3 — snap ring; 4 — piston pin; 5 — oil control ring; 6 — crankpin bearing shell; 7 — connecting rod; 8 — small-end bushing; 9 — crankpin bearing cap; 10 — crankpin bearing bolt; 11 — tab washer; 12 — peg

Piston rings

Piston rings 2 and 5 are in cast iron of special grade. If internally-stepped compression rings are used, they must be inserted into their grooves so that the machined steps are directed towards the piston crown.

Piston pin

Piston pin 4 is of the floating type.

Connecting rod

Connecting rod 7 is an I-section steel stamping, Press-fitted into the connecting rod small end is bronze bushing 8 with a circumferential groove and radial drillings serving as oil passages. Each bearing cap at the respective big end is located by a parallel detent and peg 12 and is fixed in place by two bearing bolts 10. The bolt nuts are locked by tab washers 11.