Valve Spring Shims????

[4g63telantra]

I just picked up a set of duel valve springs with Retainers and also got the shims with them. Just wanted to know what are the shims used for and where do they go? also do i need to use them?

 

[sonicnofadz]

I have taken apart several 4g63 heads before and have notice that some of them HAD shims and some of them didn't....strange. The shims do increase spring pressure since the more shims you have the less verticle space is available (and hence the pressure will increase expontentially via hooke's law) so if you could put two-three shims per valve spring it might protect against valve float and might even allow you to rev higher safely...not sure how effective it is though