Cylinder cover is the key to the engine parts, mostly with cast iron or cast aluminum.
Its structure is complex, the price is higher, if use undeserved, prone to cracks, so how to prevent the cylinder head crack?
1, the engine can't add cold water, when high temperature heat radiator boiled, cooling water evaporated, cylinder head temperature rise sharply, for lack of water more easily if the add cold water, cylinder head due to heat quenching cracks.
Therefore, we should let the engine running at low speed for a while, standby temperature drop, no longer cooling water boiling, be careful to open the tank cover slowly add cooling water.
If the tank is original and ethylene glycol antifreeze, then boiled just add water, boiling point is 197 ℃, for ethylene glycol is much higher than water, boiling evaporation of most of the water.
Without water, can't let 2 engine starting again after adding water: some engine after long-term use, starting performance is poorer.
In the cold winter, due to the difficult start, drivers often adopt measures for the error of dry water again after starting it is very harmful.
Because of fuel combustion in cylinder, if there is no water cooling in the channel, cylinder head and local temperature can reach more than 800 ℃, if add cold water, at this time due to a sudden contraction and cracks.
Therefore, engine people should be prepared before winter change garments according to the maintenance, in order to improve the cylinder pressure and keep normal work performance, fuel system to facilitate the winter starting of the engine.
In addition, when the temperature is very low, can take to the water tank to heat water, the oil temperature, hot water dash for fuel pump and fuel injector, and starting fluid injection and other auxiliary method to help the engine starting.
3, the winter not immediately after the big load assignment: water for engine using water as coolant, winter work after the completion of water must be clean, but after heavy duty engine operation, because the engine temperature is very high, if the water immediately, cylinder head casting will due to uneven temperature drops rapidly, internal stress cracks.
Therefore, we should first let the engine idling for a while, standby temperature drop off again after appropriately, and such as water temperature down to about 50 ℃ to drain.
In order to facilitate smooth water and unscrew the tank cover, after the water turns the crankshaft, to rule out the cooling water of pump in residue, can prevent the frost crack parts.
Cooling water channel 4, timely remove scale: engine after long-term use, cylinder head channel wall generates a thick layer of scale.
Main composition is not dissolve calcium carbonate scale, it will greatly reduce the cooling efficiency of cooling system, and make the parts due to uneven local heat cracks.
Therefore, we should remove scale on a regular basis.
When clearing according to 10 L caustic soda water to add 750 g, 150 g kerosene compound cleaning fluid, the proportion of injected water tank and put a net to keep the engine running after 8-10 h, plus water running 20 min, general scale can be removed.
For aluminium alloy cylinder head, usable concentration 10% acetic acid solution to remove scale.
5, do not let the captain time operation at high temperature, low speed due to launch a pilot time overload operation, cooling system, cooling, ignition or injection time is too late, fuel injection pump oil is too large or leakage of the cooling system and make the engine run water shortage, the turbocharger speed drops wait for a reason, can make the captain time is in a state of overheating, cylinder head are also prone to fracture.
Should take corresponding measures according to the different situation, make the engine work under normal temperature.
In addition, when the diesel engine fuel supply time early or uneven each cylinder oil, strong vibration will cause explosion or the body, also can make the cylinder head cracks.
6, correct installation of cylinder head, cylinder head after use for a long time, will gradually buckling deformation.
The combination of the diesel engine cylinder head flat, if its flatness tolerance than standard, must be grinding, make its flatness tolerance back to within a prescribed scope.
Otherwise not only will blunt bad cylinder pad, due to leakage and leakage of combustible gas can make local overheating, cylinder head and prone to fracture.
In addition, the cylinder head bolt with a torque wrench sequence and torque by the regulation, three times evenly tighten, momentum motives hot after tighten again, to ensure the sealing of cylinder head.