Hi,
I was just talking with my friend, complaining about how weak are valve springs on 2.4 Stilo head. (they are the same as 2.0 but with more than 10% more weight of the valve itself)

He told me about about shimming the valve springs, underneath spring locator to create more spring force. He has done it on his Uno turbo for race purposes and never had an issue with that.

Anyone know more about this shimming? I was thinking about 0.5-0.6mm shims to create more spring force and rev freely more than 8000rpm.

Thanks!

You need to absolutely sure that the valve spring isn't coil-bound at maximum cam lift, otherwise you will damage the cams / hydraulic tappets

Surely it would be easier to find some stronger springs?

Colombo&Bariani offers cams with 0.9mm more lift at intake and 0.4mm more lift at exhaust. So there is space for at least 0.4mm thick shims

It is easier to buy another springs, but I can't afford it at the moment
Found this ones, but as I wrote, wallet is empty.
http://www.bar-tek-tuning.com/lshop,showdetail,17779,en,1426701443-17779,1107452820.fiat,030602053_019,3,Tshowrub--1107452820.fiat,.htm