3 angle valve job without porting

[upontheriversky]

hi all,

im interested in modifying the head. my plan is to not widen the port size as its a small 1.0L engine and i have no intention of getting bigger intake manifold and TB. i also dont plan to smooth out the intake and polishing the exhaust as i already touched the ports and its not that rough with quite even surface, so i thought i could save money on that

i would like to do 3 angle valve job, intake port matching and milling the head, keeping the port size stock in hope of increasing smoothness in low-mid range rpm.

in terms of cost, how much will i save by not doing pnp but instead do the above?

anyone with experience please share a bit?

 

[SkYwAlKeR]

plan to do 3 angle cut but not porting it??... hmm... not many workshop can do proper 3-angle cut... if they do, normally they will ask u to do port and polish together with bench flow test...

mind u all the above will bring the cost upwards of 1k...

 

[upontheriversky]

1k..?hmm..i know there is a workshop in usj area uses serdi machine for valve cutting...

its just that i read comments from several members in other forums on pnp saying modern japanese head already have big enough port size and good design for that engine needs to begin with unlike old american head, so im a little bit confused by this...

bear with me for my ignorance here :D ..i sometimes doubt the effectiveness of flow bench to increase flow rate because it seems to only measure how many flow can enter the port but not how many in certain period.

what i understand is, when engine runs, the flow is governed by the valve lift and timing, what if the large flow can enter but too slow to keep up to the valve timing? especially on low lift, short duration stock cam? do professionals have methods to figure this out? im a newbie here :D