Information of Cylinder block

  Cylinder block.

Cylinder block, cylinder head and crankcase these three parts from the foundation and main stationary body of the automobile engines. They serve as support enclosure for moving parts. In modern engines the cylinder block and crankcase from a single casting which gives a rigid structure. The cylinder block may also have a separate crankcase for the crankshaft which is mainly confined to large engines, marine and stationary engines. A separate aluminium crankcase would result in saving the weight as well as enable cheaper and quicker replacement. 

1. The cylinder in which the piston slide up and down

2. The ports or opening for the valves

3. The passages for the flow of cooling water

The cylinder block is usually made from grey cast iron , and sometimes, with addition of nickel and chromium. Some blocks are cast from aluminium, in which cast iron or steel sleeves are used. For most engines cast iron has been found to be a satisfactory cylinder wall material, as it has better wearing qualities. In some engines the cylinder wall are plated with chromium, a very hard metal, to reduce wall wear and to increase their service life.

Tests are being carried out on high silicon-aluminium alloys to determine the possibilities as a material for cylinder block and crankcases. These alloys have a low coefficient of thermal expansion and high wear resistance.

The L head engines blocks contain opening for the valves and valve ports. The bottom of the block support the crankshaft and also the oil pan. On most engines, the camshaft is supported in the cylinder block by bushing that fit into machined holes in the block. The intake and exhaust manifold attached to the side of the cylinder block on L head in line engines.

On I head engines the manifold are attached to the cylinder head. Others parts attached to block include the water pump, timing gear or timing chain cover at front, flywheel and clutch housing at rear, ignition distribution and fuel pump the cylinder head is mounted on the top of the block. Some parts attached to the cylinder block with sealing gasket which provide a good seal to prevent leakage of water oil and gas. Some parts are attached with bolts and other with studs and nuts. In some places, lock washers are placed under the nuts or bolts heads.

Water cooled engines have passages surrounding each cylinder valve and spark plug. The circulating water maintain the engine at its correct working temperature and avoid excessive expansion and hence distortion, ultimately preventing the seizure of relatives moving parts.

The composition of a cast-iron cylinder is as follows :

• Iron 95%

• Carbon 2.2%

• Silicon 1.2 %

• Manganese. 0.63 %

• Sulphur. 0.12 %

• Phosphorus. 0.85%

A typical aluminium alloy composition for cylinder and piston consists of :

• Aluminium. 91%

• Tin. 2%

• Copper. 7%