News: In recent years, with the rapid development of science and technology, with the wide use of new materials, new technology, the level of automobile design and manufacturing has greatly improved, automobile fault detection and diagnosis technology is becoming more and more mature, automobile maintenance technology is constantly updated. However, people's understanding lags behind the development of science and technology, and the remaining errors in vehicle maintenance still have a great impact. There are 10 main manifestations:
1. The bearing bush of sliding bearing must be scraped. In modern automobiles, especially in small engines, the wear-resistant alloy coatings on the bearing bushes of crankshaft bearings and connecting rod bearings are very thin. Scraping is not allowed and can only be selected according to the corresponding size. If there is no suitable size of crankshaft bearing, the crankshaft can be grinded by the method of base hole if necessary to obtain the appropriate fit clearance.
2. Engine water temperature is not afraid of low. In fact, the low water temperature of modern automobile engine is very harmful, which will make the mixture combustion insufficient, reduce the power, increase the fuel consumption, and cause poor lubrication, and will cause excessive emissions.
3. The valve clearance is larger than the smaller one. In fact, the valve clearance is large, the valve lift filial opening is not enough, so that the intake is insufficient or exhaust is not smooth, it just reduces the engine power.
4. The more oil, the better. In fact, too much oil will do harm to the engine, especially the tilting engine and V engine. It not only increases the rotational resistance of crankshaft and connecting rod, but also increases the amount of oil splashed on the cylinder wall, resulting in the increase of coke deposit in the combustion chamber. So too much oil will reduce engine power, increase wear and tear, and also cause excessive emissions.
5. Air hub lubrication is not reliable. It is considered that the hub filled with grease can ensure the lubrication of hub bearings. It is not safe to lubricate the empty hub only coated with grease on the bearings. It is necessary to fill the gap between the hub with grease. In fact, this not only wastes grease, but also affects the heat dissipation of bearings, which is harmful and unfavorable to the lubrication of bearings.
6. The brake is good or bad. The brake marks indicate that the wheels have been locked, and the modern car just requires that the wheels can not be locked, so the anti-lock brake device is specially installed. Once the wheel is locked, the steering of the car will fail, the wheel will slip, and it is easy to break down, so it is not the longer the drag print, the better.
7. The gap of the power breaker contacts is small. In fact, the contact clearance is too large, contact closure time is short, so that the ignition coil side current reduces, resulting in weak high-voltage spark, which makes the engine difficult to start.
8. The ignition advance angle or injection advance angle is larger than the ignition angle. The deflagration of the engine causes great damage to the piston, seriously affects its service life, and the starting resistance of the engine increases.
9. Tighten the bolts tight and not loose. Actually, according to the diameter, pitch and usage of the bolts, the tightening torque of each part of the automobile has corresponding value. It is not good that the bolts which can not reach the prescribed value will loose, but if the tightening torque is increased blindly, the fastened parts will be deformed, and the screw will be elongated, the thread will be deformed or even broken.
10. When the car is maintained, it will be relieved if it is opened and checked. With the improvement of manufacturing level, the service life of modern automotive parts has been greatly extended, arbitrary disassembly and inspection is bound to destroy the running-in state. Nowadays, the automobile fault detection technology is becoming more and more perfect. Do not disassemble and inspect the parts or assemblies without obvious faults.