Valve spring math... wtf
Thread Starter
Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
Valve spring math... wtf
Posted this on thirdgen.org, but figured i'd add here as well.
This math doesn't work out...
Trickflow spring:
125 lbs. @ 1.780" installed height
376 lbs. @ 1.180" open
420 lbs. per inch rate
So at .600 lift, it's 376 lbs..
Comp 987 spring:
121@1.8 install height
388@1.2 open load
344 lbs/in
So at .600 lift, it's 388lbs..
Explain to me how, a spring that is less lbs at seat, and less lbs per inch, can be higher at the same lift? Now personally, I calculated both of them based on (lift x rate) + seat, and came up with 377 for the trickflows, and 327lbs for the comp 987's at .600 lift.. wtf Is comp's published numbers off?
I'm trying to figure out if I can use my lighter trickflow springs. The above mentioned ones are beating the snot out of my cam bearings.
Trickflow springs i'd like to use:
120 lbs. @ 1.780" installed height
300 lbs. @ 1.280" open
360 lbs. per inch rate
With my .540 lift cam, it should be 314lbs open with these, vs 306lbs open with the comps, if the comps are actually 344lbs per inch. So either comps published open pressure is wrong, their published spring rate is wrong, or my math is wrong.
-- Joe
This math doesn't work out...
Trickflow spring:
125 lbs. @ 1.780" installed height
376 lbs. @ 1.180" open
420 lbs. per inch rate
So at .600 lift, it's 376 lbs..
Comp 987 spring:
121@1.8 install height
388@1.2 open load
344 lbs/in
So at .600 lift, it's 388lbs..
Explain to me how, a spring that is less lbs at seat, and less lbs per inch, can be higher at the same lift? Now personally, I calculated both of them based on (lift x rate) + seat, and came up with 377 for the trickflows, and 327lbs for the comp 987's at .600 lift.. wtf Is comp's published numbers off?
I'm trying to figure out if I can use my lighter trickflow springs. The above mentioned ones are beating the snot out of my cam bearings.
Trickflow springs i'd like to use:
120 lbs. @ 1.780" installed height
300 lbs. @ 1.280" open
360 lbs. per inch rate
With my .540 lift cam, it should be 314lbs open with these, vs 306lbs open with the comps, if the comps are actually 344lbs per inch. So either comps published open pressure is wrong, their published spring rate is wrong, or my math is wrong.
-- Joe
