ENGINE
                    

HEAD:

 what is a cylinder head?

 -The detachable metal casting that fits onto the top of a cylinder block. In an engine it contains part of the combustion chamber and in an overhead-valve four-stroke engine it houses the valves and their operating mechanisms.

     

Whats inside a cylinder head?

       

WATCH VIDEO !!!!!

Defintion of a cylinder head>>> http://www.ehow.com/video_4908823_definition-cylinder-head.html

Theory background:  

-Seals the top of the cylinder,houses the valves,which control the flow of air fuel into the cylinder and the burned up gases out of the cylinder.

Experiment:

- Today we learnt how to measure the head by using a precision striaght edge and feeler gauge,measure the head face surface for WARPAGE. We had to check every side of the head to see if it had any gaps for leakage, to do that .We put the striaght edge on the cylinder head and the tourch behind the straight edge.If we saw any light , that means the cylinder head has a gap which is no good.

Reflection:

- Today we learnt that the cylinder head is made out of aluminum, thats valuvs are different to what i expected. I did not know how to measure the vaulves by using a micrometer and also, measuring the head with a straight edge to see if there is any gap.To see if the head will leak or not by seeing if the light form the other side will show up.

                      

Whats the difference between diesel and petrol head?











 THE BLOCK


The engine block is the linchpin of vehicles which run on internal combustion, providing the powerhouse for the vehicle. The engine block is termed a block because it is usually a solid cast car part, housing the cylinders and their components inside a cooled and lubricated crankcase. The engine block is designed to be extremely strong and sturdy, because failure of the engine block results in failure of the car, which will not function until the engine block is replaced or repaired.


The engine block is typically made of cast iron, although in the late 1990s engine blocks made from plastic and other experimental materials were being used in prototype cars with the hope of developing more lightweight, efficient vehicles. A cast iron engine block can comprise a substantial portion of the weight of the car, and usually requires multiple people to be removed and worked on safely.

Working from the outside in, the engine block starts with a solid metal outside, designed to seal everything inside. A number of channels and passages inside comprise the cooling jacket, and are designed to deliver water from the radiator to all the hot sections of the engine, preventing overheating. After the water is circulated in the engine, it returns to the radiator to be cooled by the fan and sent back through the engine.

       



The crankshaft, sometimes casually abbreviated to crank, is the part of an engine that translates reciprocating linear piston motion into rotation. To convert the reciprocating motion into rotation, the crankshaft has "crank throws" or "crankpins", additional bearing surfaces whose axis is offset from that of the crank, to which the "big ends" of the connecting rods from each cylinder attach.
It typically connects to a flywheel, to reduce the pulsation characteristic of the four-stroke cycle, and sometimes a torsional or vibrational damper at the opposite end, to reduce the torsion vibrations often caused along the length of the crankshaft by the cylinders farthest from the output end acting on the torsional elasticity of the metal.

     




  Piston stroke
The distance the axis of the crank throws from the axis of the crankshaft determines the piston stroke measurement, and thus engine displacement. A common way to increase the low-speed torque of an engine is to increase the stroke, sometimes known as "shaft-stroking." This also increases the reciprocating vibration, however, limiting the high speed capability of the engine. In compensation, it improves the low speed operation of the engine, as the longer intake stroke through smaller valve(s) results in greater turbulence and mixing of the intake charge. Most modern high speed production engines are classified as "over square" or short-stroke, wherein the stroke is less than the diameter of the cylinder bore. As such, finding the proper balance between shaft-stroking speed and length leads to better results.

Pistons

Engine Oil Pan


The oil pan is located at the bottom of the engine, and on most cars and trucks is used to hold the engines oil. Most cars will have wet sump-oiling system where engine oil is kept underneath the engine in an oil pan. Typically a oil pan will be made of steel or aluminum and hold 3-10 quarts of oil for lubricating the engine. The oil pan generally gets deeper the farther back it goes. This is to keep a supply of oil ready for the oil pump when the car is accelerating, braking or cornering.

The quantity of oil the oil pan holds is usually related to engine size. Larger displacement engines will have a larger oil capacity and will need a larger oil pan. While you normally would not think of an oil pan needing replacement there are reasons where you would need to do so. You may need a new oil pan if yours has had the oil drain plug stripped, has gotten dented or has been punctured.

Some enthusiasts choose to upgrade their oil pan to a higher capacity, aluminum type. This helps to dissipate heat and keeps oil ready for the oil pump to use even under extreme driving conditions. These oil pans are mostly used for racing. Most consumers simply purchase a stock OEM, genuine or aftermarket oil pan. Installing a new oil pan is a pretty basic job and most should be able to perform this job at home with common hand tools. Labor on this job is not very expensive if you are unable to do this yourself.