As we have seen previously, one of the constituent parts of the engine is the block, in which there are cylindrical-shaped holes where the pistons that move thanks to combustion are inserted. These holes can be exposed (as in most current engines) or covered by some shirts.
Be they wet or dry, the shirts are cylinders that act as receptacle and chamber. Their two main advantages regardless of their type are: first, they are made of a material that is more resistant to friction and heat, and therefore the surface of the block they cover does not have to be treated. Second, they can be replaced if they wear out.
dry shirts
They are just some cylinders made of metal which are inserted into the holes in the engine block. They are called that because do not come into contact with engine coolant and only touch the block itself. They can be divided into two types according to the assembly process and work they require:
Semi-finished dry shirt
They receive this nickname because although their exterior is completely prepared, the interior is not rectified, nor burnished. They have a considerable wall thickness, which allows them to mount them on the pressure block without being deformed by a press. They are slightly larger than the hole in which they are going to be inserted so that they are perfectly fixed. What is called dry mounting.
Dry shirt finished or chromed
In this case, the interior is already ground and burnished to the right size for the piston and its rings. Are thinner and are installed without a press because they would be deformed. Hence, they are the same size as the hole they are going to cover in the block.
Within the dry shirts, a type whose origin is very old could be included: the air cooled jackets. As can be deduced from their name, they are not in contact with any coolant. They are cylinders that are inserted into the block only partially, the rest goes on the outside and has fins to expand the surface in contact with the air and improve cooling.
These air-cooled dry jackets are usually encapsulated together and cooled by inlet and outlet fans. That is, a forced ventilation.
wet shirts
In the case of wet shirts, the coolant does come into contact with the liner itself, so there is a gap between her and the block for her to pass through.
They have a step or seat at the top or bottom, which is where they sit on the block. To create said coolant hole, they have some O-rings and washers that act as gaskets so that the liquid does not leak. They can be mounted on:
- el engine block, in such a way that they are pressed against the shirt or
- la shirt, in such a way that they are pressed from it against the engine block
El space What's between those O-rings? It may be somewhat lowered to leave more space so that the liquid circulates and better eliminates the heat that is generated inside the shirts with the detonations of the engine.
Also, wet shirts are perfectly closed thanks to rubber rings or other materials placed both in its upper and lower part. With what they can be easily mounted on the block, without resorting to excessive pressure.
It's a very solid system. carry most commercial vehicles. It is very effective to adequately cool the engine due to the proximity of the coolant to the place where the heat is generated. In such a way that it is easy to maintain the average service temperature and we increase their longevity.
direct shirts
Finally we could add the direct shirts to the list, which is another way to call the direct block. In this case, it is the block itself that is rectified for the ones piston rings are in direct contact with him. Besides that it is given a hardening treatment to the cylinder surface.
Pictures – Colin, pwjamro, Lisa Ann Yount
Good !! I don't know much about engines and I have a doubt about the images you have exposed, the first photo corresponds to a block of wet shirts n? and the second with an integral block n? because I don't see that it is about dry shirts, I would appreciate an answer.
Greetings, the skoda fabia engine liners came loose and I bought new ones but they enter the block without pressure…they recommended high-resistance loctite….these liners are wet…what can I do?
Hello!! In my experience we have noticed that the Nissan engines, the so-called QR25, are having problems, we mean mixing water with oil, all aluminum monoblocks tend to crack sooner or later.
hello, how are you, I have a question, I removed the sleeves of my black cht 1.6 motor from a vw saveiro, and I didn't find a rubber oring, but copper washers. yes or if they have rubber orings. I suppose that the copper washers will be to give the height to the shirts with the pad? I ask this because an acquaintance put it together for the motor, and in the rectifiers that sold us the subassembly they did not give us rubber orings, and he put the copper washers and glue, but it failed
I have a Volga with a floating liner and it took the Block Gasket and when I disassembled I noticed that the liners are half a mm above the Block. It's normal ok I have to do it.