Camshaft setting?..

[nakal_7]

is it a must, when we use a high cam so then we must setup and adjust the cam using the adjustable cam pulley? let say i buy a 272 camshaft, so i can still use the stock timing
cam pulley is it? or i must do some adjustment?
what the different when we advance and retard the inlet cam? and same goes to outlet, what the diff when we advance and retard the cam? and what the purpose?

thanks :shocked:

 

[edwin_lcw]

dunno how to explain but sure must do some new setting .... on high cam ..... if dun do then its like no effect before n after

 

[Fluffy]

when u get a high cam like that..using the stock pulley will kill u during idling.ur idling will be very low.

so better u get an adjustable pulley and advance the timing.

IMO.

 

[rollakid]

you need standalone ecu as well.

i think there's an awsome article by bill sherwood in his site about cam timing, for 4age at least, but an engine is an engine is an engine, so it won't differ too much i guess. www.billzilla.org

 

[Zeroed]

Not necessary... the valve overlap on highcams gives you valve opening duration gains on both sides before and after TDC...
The adjustable pulleys will let you further adjust your powerband only, whether you want more gains at medium or high rev. With the stock pulleys you will already have quite a lot of gains, but by tuning it with adj. pulleys you can gain a bit more of maximum hp (but lose hp elsewhere).
Unless youre talking about very high degree race cams, then it really depends on the cam design.

Advancing the timing will kill your idling even more actually...

 

[edwin_lcw]

i agree with zeroed .....

 

[boyzone]

actually there is no advise to go to hi cam before completed done on pnp, engine internal upgrade etc... then remapping ecu or sub ecu will the next step u need to look for after hi cam installed.
change cam will shift engine power bias.

 

[nakal_7]

hmmm... assume thats i have all the things like standalone management system, upgraded engine and etc. what i have here, i advance the inlet timing about 4 degree and for the outlet 0 degree. when on dyno machines its seems that on the 8000 rpm the torque drop very sudden. so?....
for your informations, im using crower cam stage 3. duration 260 inlet and 258 outlet (part number 64414) with the adjustable cam pulley. and im used 4G63 engine with the standard stroke and oversize piston. for turbo im using Garret GT30. with oversize valve, titanium retainer, upgraded the valve spring.
in the timing tag its said that all the information for the cam are taken on the stock timing pulley. is it that i better try it first on the stock cam pulley or what?
for your informations, when on 8500 rpm the horsepower are constant but not the torque.
thanks

 

[Zeroed]

Generally for high rpms you want to retard the intake. Advanced intake will give you better mid range but at high rpms you want the intake valves to close later as the siphoning effect of the exhaust extraction becomes less important and freash air needs a longer time to rush in instead. I would try the standard setting if the cams seems to be meant for standard timing lor.

All these depend on the engine setup but the general rule VVTs use in valve phasing is retard-advance-retard from low to high rpms... This ive been told by a well trained mechanic... gotta catch up with him one day also...

From personal experience, I lost top end but gained in mid range when I advanced my timing as well. Like you mentioned, torque drops quite noticeably.


edit: made a mistake XD