how does hi cam work?

[SkYwAlKeR]

Hehe..degree in doctor ayam...my hand are itchy to get this hi cam for my car.Can anybody suggest a good workshop in JB to tune it.:hmmmm:

viswork??...

wat's the stock duration for exhaust and intake angle? anyone noes? for wira se i mean..

240 intake
244 exhaust
0.24 intake valve lift
0.24 exhaust valve lift

 

[Choon]

wow, that mean 272 is already alot of gain.. let me count.. *reaches calculator* 13.3% longer duration for intake.. but long duration normally only good for higher rpm because the overlap would be more..

 

[Joeker]

Every engine mod has to complemented.

In the case of "hi-cams", you'll also need matching gear ratios to fully harness its power.

most Modern day engines are 24x ~ 25x degrees cam profiles.

For street use, 26x~27x is enuff. I don't think you'll need stiffer valve spinrgs and retainers unless you plan to rev to the moon and the stars

For SOHC 4G13~15 engines, wat we use to do was grind the heel of the lobe by a couple of mm and then compensate it from the rocker. We get slightly more valve overlap and thus, a DIY-ed "hi-cam" Abit more OMMMMPPPHHH!!!

 

[SkYwAlKeR]

For SOHC 4G13~15 engines, wat we use to do was grind the heel of the lobe by a couple of mm and then compensate it from the rocker. We get slightly more valve overlap and thus, a DIY-ed "hi-cam" Abit more OMMMMPPPHHH!!!

how to compensate it from the rocker??... closer valve clearance??..

i've heard of mechanics grinding a few mm off place where the rocker arm shaft sits... this lowers the rocker arm and hence allowing higher lift on standard cams....

 

[Joeker]

i've heard of mechanics grinding a few mm off place where the rocker arm shaft sits... this lowers the rocker arm and hence allowing higher lift on standard cams....

Yes, it works just as well. either grinding the, as you say it, "rocker arm shaft sits" or grinding the cam's lobe heel, will result in higher lift & more overlap and you have your DIY-ed "hi-cam"

When the cam lobe heel is grounded off, there will be a larger clerance between the heel and rocker arm.

Using a feeler blade, you need to close down this clerance as you would do when you adjust the rockers arm screw to get rid of the irritating the infamous "tappet noise" problem of 4G15/13

 

[SkYwAlKeR]

Yes, it works just as well. either grinding the, as you say it, "rocker arm shaft sits" or grinding the cam's lobe heel, will result in higher lift & more overlap and you have your DIY-ed "hi-cam"

When the cam lobe heel is grounded off, there will be a larger clerance between the heel and rocker arm.

Using a feeler blade, you need to close down this clerance as you would do when you adjust the rockers arm screw to get rid of the irritating the infamous "tappet noise" problem of 4G15/13

means i can jz increase the lift of my cams by adjusting the valve clearance closer together la??... of coz not too close till piston clashes with the valve...

 

[Joeker]

Yes, slight longer valve open duration and higher lift. if not mistakne, we grounded 2mm off the cam lobe's heel.

 

[SkYwAlKeR]

Yes, slight longer valve open duration and higher lift. if not mistakne, we grounded 2mm off the cam lobe's heel.

icic.... in fact there are many innovative modifications can be done on the valvetrain to increase the duration and lift without changing to high profile camshafts...

malaysia boleh... wuakakaka...

 

[Choon]

wah.. pakai grind grind oni ah.. dangerous leh.. all diy king here..

 

[SkYwAlKeR]

wah.. pakai grind grind oni ah.. dangerous leh.. all diy king here..

i dunno how to do one ler... its one of those legend stories made up / created by local malaysia boleh mechs...

 

[nerwean]

if using hi cams 280 degree and lift 11mm in 4G93P stock head, is it safe for piston head? can be hit by valve or not?

 

[kenzo]

adjustable cam pulley would be handy

 

[SkYwAlKeR]

if using hi cams 280 degree and lift 11mm in 4G93P stock head, is it safe for piston head? can be hit by valve or not?

what is the standard cam lift for 4g93p cams??.. if below 11mm, it is adviseable to use stiffer valve spring... and make sure ur cam degreeing is set nicely....