First we take a look at the cam pulley itself. Cam pulley is used to rotate the camshaft which in turn will push the valve down.The timing of the valve will depend on the camshaft and the cam pulley.The timing means when the valve is pushed down. If the valve comes down before the piston reaches its highest point called the top dead center(tdc), the timing is considered ADVANCE.If the valve comes down after the piston reaches the tdc, it is considered as RETARD. The advance/retard is measured by degrees for example advance 2°or retard 2°.
The adjustable cam pulley, as the name implies, it means the pulley is adjustable.This will allow the valve timing to be changed This is simillar to a vvti system except the timing on vvti engine is variable depending on engine speed and it it is changed while the engine is running.As for the adjustable cam pulley (acp), the timing can only be set at one position/angle and can only be changed when the engine is not running.
WHY ADJUSTABLE CAM PULLEY?
Different timing is needed for different speed of engine (rpm) to get the most efficient combustion.The cam pulley can be adjusted to suit the driving style of the driver. The powerband of the engine can be shifted by varying the timing of the valve.
ADVANCE TIMING.
Advance timing means the valve start to come down before the piston reaches the tdc. The advance timing will enhance the lower and mid range of the engine but peak power will be less. This setup is suitable for daly driving in the city where the engine revs at low to mid rpm levels.However if the timing is too advance, it can cause detonation/knocking/pinging
RETARD TIMING
Retard timing in the other hands means the valve starts to come down after the piston has reach its tdc.Retard timing will enhance the high the peak power but sacrificing the mid and low range power. This setting is suitable for drag or racing purposes.
The valve/cam timing is usually altered together with the ignition timing
COMMON CONFUSION OF VALVE TIMING, LIFT AND DURATION
Note that the adjustable cam pulley only changes th time when the valve activity start. The duration the valve will remain open is still the same and the lift/depthness of the valve being pushed down is also the same.
saya ingin bertanya pihak ekereta..adakah tempat yg boleh membaiki microtec mt8…sekian terima kasih
try tanye millenium motorsport, manela tau diorang boleh buat ape2 ke
tune kt mane microtech tu?keta ape, citela sket, aku pon kaki keta gak, pakai b6
ni contact diorang
mobile: +60123205454
office : +60356325707
email : millenniummotorsports@gmail.com
web : http://www.millennium.com.my
blh terangkan mcm mana adjustable cam pully berfungsi,sehinggakan ia boleh meningkatkan kuasa ke atas sesebuah kreta..
bukan tingkatkan kuasa semata2, cume shift powerband ke tempat lain,
baca article kat atas dh ade explanation semua
function retard dgn advanced sama ke untuk inlet ngan exhaust cam? bila adjust inlet, exhaust macamana? nak kena adjust berlawanan ke tak perlu? saya br pakai, cuma dalam mencari lagi timing yg bagus.
Sebenarnya…adjustable campulley ni x melajukan km/h kete anda…cuma dia bg pickup lebih je kat kete anda…sesuai utk kt traffic lite, nak kuar simpang dan yg seangkatan dgn nya…kalo nak laju, beli la kete sukan…..sbb kalo anda sume x syg kan kete2 anda dan duit dah byk, buat la modified yg bukan2 kat enjin kete anda….byk faktor perlu di ambil kira utk melajukan lagi km/h kete anda spt ekzos size, intake system, firing, fuel, ecu (bg injection), carb, dan mcm2 lagi lah…so, drive smart dun drive crazy..huhu
aku rase, kalau enjin pakai single cam pulley, kurang sikit ko leh main, kalau enjin 2 cam pulley bole adjust max.
salam,
saya kurang faham tentang berapa degree yg nk dilaras pada intake dan ekzos.boleh beri tips macam mana nk dapat set yg cun utk twin cam samada advance(in) dan retard (ex),retard/adv,adv/adv,ret/ret dan berapa degree.maksud saya samada lebihkan degre pd (in) dan kurangkan pd (ex) atau sebaliknya.lagi satu nk tanya pada yang berilmu pernah dengar/tahu cara nk laras CRANK ANGLE degree(bawah).bagaimana ia boleh meningkatkan power band pada enjin.
rampland, wsalam
seeloknya nak adjust acp ni dibuat oleh mechanic yg berpengalaman dgn jnis engine tuh
kalau adjust2 sndiri takut silap2 piston langgar dgn valve plak,
sy sndiri pon tade experience nak tune degree acp ni
saje nk tau untk tambah sedikit ilmu coz kalau tanya kat mekanik takde jawapan yang sama dan tidak bertujuan utk buka bengkel pun.Ape2 pun tima kasih sudi balas pertanyaan saya.
hi all…
aku pon ade nk tanyer same cam bro ater….kalau DOHC, nk dapatkan high torque, mcmner setting tebaik?in retard,out advance ke?
TQ
bro, utk setting lg elok dapatkan nasihat dari tuner or mechanic yg dah biase buat benda ni
bcoz saye sndiri pon tade hand on experience utk tuning acp ni
so sy x brani nk recommend ape2
Antara advance timing dgn Retard timing, mana satu yg gune fc lebih..??
dulu sy pki acp ni mmg pick up ok tp skg da buka… pick up mmg terasa kureng
bro.. nak tanya nie.. kalau nak pasang bende nie.. senang ke susah nak ejas.. esok nak pasang bendalah nie.. tapi lepas baca macam tak konfiden pulak nak pasang.. tgk muke pomen tadi pun siap tny lagi ape bende ACP nie.. takut kang dia belasag pasang. tak pasal2 kene beli enjin baru..
Saya mahu bertaya sedikit tentang suspensen sy slalu brbunyi di bahagian blakang knape ye??