~~CAMSHAFT~~

The camshaft is an apparatus often used in piston engines to operate poppet valves. It consists of a cylindrical rod running the length of the cylinder bank with a number of oblong lobes or cams protruding from it, one for each valve. The cams force the valves open by pressing on the valve, or on some intermediate mechanism, as they rotate.

Timing

The relationship between the rotation of the camshaft and the rotation of the crankshaft is of critical importance. Since the valves control the flow of air/fuel mixture intake and exhaust gases, they must be opened and closed at the appropriate time during the stroke of the piston. For this reason, the camshaft is connected to the crankshaft either directly, via a gear mechanism, or indirectly via a belt or chain called a timing belt or timing chain. In some designs the camshaft also drives the distributor and th

e oil and fuel pumps. Also on early fuel injection systems, cams on the camshaft would operate the fuel injectors.

In a two-stroke engine that uses a camshaft, each valve is opened once for each rotation of the crankshaft; in these engines, the camshaft rotates at the same rate as the crankshaft. In a four-stroke engine, the valves are opened only half as often; thus, two full rotations of the crankshaft occur for each rotation of the camshaft.

The timing of the camshaft can be advanced to produce better low end torque or it can be retarded to produce better high end torque.

Duration

Duration can often be confusing because manufacturers may select any lift point to advertise a camshaft's duration and sometimes will manipulate these numbers. The power and idle characteristics of a camshaft rated at .006" will be mu ch different than one rated the same at .002". Whenever duration is quoted, be sure to note the lift at which it is given.

Many performance engine builders have learned to gauge a race profile's aggressiveness by looking at the duration at .020", .050" and .200". The .020" number determines how responsive the motor will be and how much low end to

rque the motor will make. The .050" number is used to estimate where peak power wil

l occur, and the .200" number gives an estimate of the power potential.

In general, duration determines how many crankshaft degrees a camshaft maintains more than a given tappet lift.

as per explaination.... keupayaan sesebuah engine mampu di tingkatkan lagi dengan sedikit penambahan deg atau penukaran camshaft kepada yg lebey berkeupayaan tggi... *ala-ala gitu la.... senang citer giler kuasa tukar jer cam..ehehe ader bunyi brub-brub agi... tu yg best tue..ehehe

~~tapi satu la pasang cam ni... MINYAK memang bes t...ahah macam air beb... Pastu bunyi brub...brub...brub... tu menarik perhatian abg J.... abih la.. takut aku pasni...

~~degree sesuatu cam itu pulak menerangkan jenis atau kesesuaian cam itu sendiri... maklumat dari org la... ader mildcam, fastroad,racing cam, extreme cam...bla...bla...bla...bla...bla... aku pon tatau...

~next modification dalam engine aku kali ni... aku menukar camshaft 4g92p yer berdegree kurang dari 250 (*orang cakap*) kepada sesuatu yg lebey ekstrem.... aku akan menggunakan cam yang berdegree lebey tinggi...ehehe
nantikan...



antara gambar2 cam asal a.k.a 4G92P