LO 8-5 Identify and describe the configuration and construction of common cylinder block cylinder arrangements

Dry Sleeve Blocks

A dry sleeve cylinder block is designed with a bored or honed hole in the block that allows no coolant contact with the cylinder sleeve. The sleeve is inserted into the bored hole as either a slip or an interference-type, pressed-in fit. If the liner is installed with an interference fit, meaning the liner is slightly larger than the cylinder bore, it does not usually have a top flange, but it is machined flush with the block deck. A slip-fit liner will use a counterbore machined into the block to accommodate the liner flange, and the flange locates or seats the liner into the block. These liners are usually lubricated externally with engine oil to ease installation Figure 39. Pressure, applied by the cylinder head to a slight protrusion of the liner flange, will prevent liner movement.

FIGURE 08-39: Comparing dry and wet liners.

Aluminum blocks will use hardened iron alloy sleeves, which are cast in place and not removable. To replace these sleeves, the liner is cut out of the block with a machine tool and a new one is pressed in place. In other blocks with field replaceable dry sleeves, the dry sleeve’s advantage is the absence of contact with coolant that could cause sleeve corrosion. Additionally, the absence of coolant contact means there is not a requirement to seal the sleeve with O-rings or special sealing surfaces to prevent coolant leakage into the crankcase. Cylinder sleeves may be replaced individually if they become prematurely worn or damaged.

Dry sleeves have some disadvantages. Because the coolant is not in direct contact with the dry sleeve, heat transfer from the combustion chamber to the liquid coolant is not as rapid as it would be with a wet sleeve. This slow heat transfer may potentially result in limitations on power output per cylinder, shortened engine life, and cylinder damage. Extra steps in manufacturing and machining the block are required for sleeve installation. Dry-sleeved blocks tend to weigh more than parent bore blocks.