Guys,
N1 pistons runs perfectly with N1 cams, regardless the head shaved 1mm, so valve 1mm closer to piston. Right? And AFAIK N1 piston notches are the same as on 16VE piston.
As soon as piston to deck clearance on 16VE pistons are the same as 20VE pistons - we have no problem running 16VE pistons with N1 cams.
As I measured some days ago, with 16VE pistons in TDC you have ~5,5mm of valve lift. I think this is enough clearance to be safe.
Regarding springs, I think you should go with stock springs if you're in tight budget.
If you have enough money - just buy N1 springs and retainers.
- They are produced to run with N1 cams.
- The springs are SOFT. The 20VE much stiffer.
But do you need another mechanical losses in your valvetrain if you will be safe enough with N1 cams/spring/retainers also?
They are FACTORY designed to run in combination one with other.
Also I think N1 cams/springs/retainers have tested to not have harmonic resonances.