2.2.4. Check of technical condition of engines 420.10-10, 421.10-10, 4213.10

Technical condition of the engine is defined by a fuel consumption, engine capacity, pressure and a consumption of oil, a compression in cylinders, the noise level of the working engine and smoking of the engine.
Control consumption of fuel the deputy-ryayte on the car (after the run not less than 9000 km) moving on the highest transfer with full loading on the dry flat asphalted or concrete road with a speed of 90 km/h. Peredny Bridge and wheels have to be disconnected thus.
You carry out measurement on the section of the road 3-5 km long in two opposite directions. Before arrival warm up the engine and units of the chassis, having executed a run of 10-15 km.
During the winter period the control consumption of fuel can increase no more than by 10%.
Power qualities of the engine are determined by dispersal and the largest speed of the car.
Determine technical condition of units of the chassis by the size of a vybeg of the car. On the flat section of the asphalted highway at the movement with the established speed of 50 km/h switch off transfer and let's the car move quietly to a full stop. Выбег measure at arrivals in two opposite directions.
You carry out check of control fuel consumption and a vybeg of the car during the normal operation of the engine on external signs. Before it check and if necessary adjust pressure in tires, a convergence of forward wheels, completeness of a disinhibition of brake mechanisms. Wear of a protector of tires has to be no more than 50%.
The running gear is in a serviceable state if at the car (after the run of 9000 km) выбег not less than 500 m.
The oil consumption in process of operation of the engine does not remain to constants: in process of a running in it decreases and after the run of 5000-7000 km there are equal 70–150 g on 100 km of a run. After the run of 70 000-90 000 km the consumption of oil increases. If the consumption of oil exceeds 450 g on 100 km of a run, then the engine demands repair. Measure a consumption of oil by method of a doliv.
Check oil pressure in the lubrication system the control manometer with the division price no more than 49 kPa
(0,5 kgfs/cm2) which is connected by means of a flexible hose instead of the oil pressure sensor. For measurement of pressure of oil on the motionless car lift the back bridge on supports, switch off the forward bridge, launch the engine and, having included a direct pe-redacha, open the throttle gate of the carburetor so that the speedometer showed the speed of 45 km/h, measure pressure in system.

Fig. 56. Check of a compression in engine cylinders


Check a compression in cylinders on the heated-up engine kompressometrom. For this purpose turn out spark plugs, insert a rubber conical tip kompressometra into an opening for a candle (fig. 56) and it is old-terom turn a bent shaft at completely open throttle gate and the carburetor without fuel. Pressure in cylinders has to be not less than 660 kPa (6,65 kgfs/cm2). The difference of pressure in cylinders should not exceed 98 kPa (1 kgf/cm2).
Evenly lowered compression in all cylinders testifies how the rule, about considerable wear of cylinders and piston rings. Decrease in a compression in separate cylinders can happen in result of "lag" or a burn-out of valves, a prigo-raniye or breakages of piston rings, damages of laying of a head of the block of cylinders or violation of adjustment of gaps to the valvate mechanism. If when filling 25–30 cm3 of pure oil in the engine cylinder from lowered a lump-pressiyey pressure in it increases, so there was a breakage of piston rings or their coking up in piston flutes. If thus the compression does not increase, then the reason of a neis-pravnost needs to be looked for in leakage, lag and obgoranii valves or in damage of laying of a head of the block of cylinders.
Decrease in a compression in two next cylinders indicates damage of laying of a head of the block of cylinders.

Fig. 57. Zones of listening of the engine: 1 – gear wheels distributive; 2 – valves; 3 – fingers piston; 4, 5 – pushers, bars of valves, bearings of a distributive shaft; 6 – bearings radical bent shaft


Listen to knocks and noise of the engine a stethoscope on the heated-up engine with various frequency of rotation of a bent shaft (fig. 57).
Begin listening with the distributive mechanism at a small and average frequency of rotation of a bent shaft: valves at 550–1000 min.-1, pushers at 1000–1500 min.-1, distributive gear wheels at 1000–2000 min.-1.
Knocks of valves are clearly listened from the party of a head, over places of an arrangement of valves; knocks of pushers and necks of a distributive shaft – from the party of an arrangement of the raspre-delitelny mechanism, at the level of an axis of a distributive shaft; knocks of distributive gear wheels – from the party of a cover.
Krivoshipno-shatunny wiretap the mechanism (pistons and radical bearings) at sharp change of frequency of rotation of a bent shaft of the engine in limits of 500-2500 min.-1.
To define in what cylinder the krivoshipno-conrod mechanism knocks, serially remove from wire candles.
Most clearly knocks of bearings are listened on case walls from the right party at the level of a distributive shaft; knocks of pistons and piston fingers – on cooling shirt walls against the corresponding cylinders.
Knocks of radical bearings – deafs, and knocks of conrod bearings and piston fingers – sharper and ringing. Knocks of pistons – sharp, jingling. They can be listened on all modes of operation of the engine.
Knocks of pistons, piston fingers, radical and conrod bearings, valves and pushers on the heated-up engine testify to malfunction of the engine.
The increased knock of valves and pushers merging in the general noise of the engine at increase in frequency of rotation of a bent shaft or the periodic knock of valves appearing and disappearing at sharp change of frequency of rotation of a bent shaft and also insignificant knock of pistons on neprogretom the engine are not signs of malfunction of the engine. Let's allow also insignificant noise of high-pitch tone from work of distributive gear wheels and gear wheels of the oil pump.