Chalk me up for another cam question.
Jan 22, 2014 | 08:02 AM
#31
I don't understand you're guys' reasoning behind not being able to run ".600" springs... Yea any idiot can read that the manufacturer recommends a max of .600" of lift but does anyone ever check the actual specs of the springs. Did anyone ask if he is going to run these springs at a specific installed height? Obviously all of this plays a roll in what springs to run.
If you look at the 918's, comp states they provide 130lbs of seat pressure at a 1.800" installed height. They state that coil bind happens at 1.100". So if you install your springs at 1.800", then you have 0.700" of travel before a possibly running into coil bind. Usually manufacturers keep the spring anywhere from 0.050"-0.100" away from coil bind. In this case, comp "rated" these springs to .600" max lift to give you a .100" cushion.
So the fact that his exhaust lobe is supposed to be ground somewhere around .602" lift doesn't tell me that the ".600 max lift" springs can't be used... There are too many variables in the valve train to make that assumption. Its garenteed that not all of his installed heights will be 1.800". One could be 1.805, another could be 1.795. That is why the cushion is built into the rated max lift.
If you look at the 918's, comp states they provide 130lbs of seat pressure at a 1.800" installed height. They state that coil bind happens at 1.100". So if you install your springs at 1.800", then you have 0.700" of travel before a possibly running into coil bind. Usually manufacturers keep the spring anywhere from 0.050"-0.100" away from coil bind. In this case, comp "rated" these springs to .600" max lift to give you a .100" cushion.
So the fact that his exhaust lobe is supposed to be ground somewhere around .602" lift doesn't tell me that the ".600 max lift" springs can't be used... There are too many variables in the valve train to make that assumption. Its garenteed that not all of his installed heights will be 1.800". One could be 1.805, another could be 1.795. That is why the cushion is built into the rated max lift.
If anyone else asked this question the response would have been, it isn't you best bet but you should be just fine. Don't spin to a million RPM and know you may break a spring in 6 months or a year, but they could also last forever.
Since it is me and the specks are off a hair people are freaking out. I am not going to prove them wrong since I have the .660 springs but I am quite confident that they would work and last for a long time.
All that being said I really like the idea of a dual spring and the insurance of plenty of spec left! I have seen a lot of threads with a broken spring. Either lots of damage or the dual spring saved them.
Last edited by AKlowriderZ71; Jan 22, 2014 at 09:36 AM. Reason: Removed foul language
Jan 22, 2014 | 01:46 PM
#32
Hey I'm all for giving you **** but when ignorant advice is being given it needs to be corrected. 
Mangled, you need to take into account all the variables. Seat pressure, installed height, ect. Then find a spring that fits within your build specs. The higher the spring "max lift rating" is, usually the higher the seat and open pressures will be. If your cam can only handle X amount of pressure, then you have a boundary that needs to be taken into account. Different lobes like different pressures. And so on and so on..
Mangled, you need to take into account all the variables. Seat pressure, installed height, ect. Then find a spring that fits within your build specs. The higher the spring "max lift rating" is, usually the higher the seat and open pressures will be. If your cam can only handle X amount of pressure, then you have a boundary that needs to be taken into account. Different lobes like different pressures. And so on and so on..
Thread
Thread Starter
Forum
Replies
Last Post
lawhitediamante
INTERNAL ENGINE MODIFICATIONS
5
Aug 12, 2015 12:14 PM