La bed It is one of the lower parts of the engine. It is where the crankshaft is attached and therefore one of the most important parts of the lubrication circuit. It must have a very high resistance to withstand the great efforts that occur within it.
This part can have several designs, depending on the power, the motor structure and also the forces to which it is exposed. Normally, the base is made of cast iron, with all the holes and shapes necessary to join with the rest of the pieces.
bench function
In order to fully understand what its function is, it is convenient to have clear what parts does it relate to. The mount of an engine has bolted below the sump and above the engine block. Inside it houses the crankshaft, so it usually has hemispherical surfaces to allow its rotation.
Taking this into account, it can be seen that the bench has a structural function. It is the part that gives solidity to the engine and closes it below. The three basic parts would be from top to bottom: the butt, which closes the motor from above, the engine block, which is the middle part where the combustion chambers and go up and down pistons, and finally the bedWhere houses the crankshaft which is moved by Rods that go to the pistons.
bed resistance
the bench withstand enormous forces due to crankshaft rotation. The connecting rods make it rotate alternately according to the piston or pistons that are applying the expansion force inside the cylinder. Moment in which the bench receives a great force that pushes it downwards. Its fasteners and the very integrity of the bedplate have to withstand these and other forces without breaking.
La advantage of this part, regarding the resistance that it must have, is that eis further away from the combustion chambers and therefore of the pressures and the temperature that are generated in them. Perhaps that is why you have heard the failure of "the cylinder head gasket" or "cylinder head deformation" with some frequency and never or almost never of the cylinder head.
Of course, we must not forget that the bench also has to withstand the engine temperatures which is driven by metal and the refrigeration system. In addition to the lubrication circuit pressures generated by the oil pump, motor movement and temperature.
Engine mount parts
Although it really is a single piece of metal, can be divided into several parts that perform different functions. Normally it is a rectangle crossed by several cross beams to give it more solidity. No matter how hard the metal is, if it is not well thought out it will deform over the kilometers.
- longitudinal beams: are usually simply the long sides of the rectangle. They are the ones that withstand the longitudinal deformation that may affect the bench. To get it right, imagine trying to break or deform the rectangle by squeezing or pulling on its short sides.
- cross beams: they fulfill the same function as the longitudinal beams but in the other direction. That is, they support transverse deformation.
- crankshaft housing: the crossbeams have semicircular holes to place the crankshaft so that it can rotate.
- Block support surface: as we have told you before, the bedplate has the engine block on top. If the contact surface between these two pieces is not perfectly smooth and flat, they will end up deforming and having gaps.
Engine mount faults
It is an element of great resistance, so it is quite strange that it breaks this part of the engine. However, we can find some cases in which the engine breaks in this part, although it is something really strange, which may be due to manufacturing defects or an accident.
Where can faults be found? more often it is in some related elements. For example, the bench is attached to the car by several rubber supports that can deteriorate. These supports absorb the vibrations produced by the engine, so that they are not noticed inside the car, which provides greater comfort. Typically, a vehicle has at least three mounts. The first support is located on the side of the distribution, the second on the side of the gearbox and, the last support is found in the lower part of the engine.
On the bench is part of the engine lubrication and cooling circuits. So there may also be some problem in the joints that can cause some loss of these liquids. Although it is very unlikely to happen if the engine has always worked at normal temperatures that cannot cause serious wear or deformation.