Quote:
Originally Posted by 19bonestock88
The stock valve springs are the limiting factor for revving high, all stock Ecotec valve springs are good to 7200 RPM. They sell stiffer ones but I wanna avoid getting them in an effort to avoid excessive friction. I guess I could do titanium valves and keepers/retainers to save weight and maybe gain some revs on stock springs but that’s awfully spendy for an under 200whp engine
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Stiffer springs (or cams with very aggressive ramp) cause timing-related failures in K series. General rule there is to stay stock, or you need to seriously improve the tensioner and guides. And then your timing chain life is still reduced. I've seen 500HP NA builds with a K series, but building for NA power ends up being more of a rabbit hole in terms of cost and reliability than forced induction.
EDIT: I've also read of titanium and inconel valves causing rapid wear of valve guides. Definitely read up before choosing any exotic materials, they almost always have some kind of drawback.