StupidFast

I would like to know if there is a single valve spring that will work with this much lift. I don't want to change the springs every 10,000 miles or anything. Suggestions.

Beast96Z

iTrader: (21)

In a single spring, the comp 918's would work, but your getting them close to there limit. A good factory replacement double spring would add life and be much more "safe" than a 918. Comp, crane, and Patriot offer very nice dual replacement springs that fit with no modifacation.

mrr23

iTrader: (3)

http://www.vincihighperformance.com/...RTSPARENT.HTML well their single handles only .530 but the dual will handle .650 lift. give them a call to see if they have a single to fit your needs.

StupidFast

Would there be a problem with the 918s and this much lift?

Beast96Z

iTrader: (21)

Harshness of the lobe also plays a factor. Personally I wouldn't use the 918's on an aggressive lobe, but if the lobe is softer, it should be fine.

KJ

iTrader: (1)

I would think of it like this, If a valve spring should fail what kind of damage is going to happen & what will it cost to fix it! I would think long and hard before using a single spring. It may not break right away, but will fatigue quickly. You will probly notice valve float when you reach higher RPM's. I would use the Crane dual spring. It's good to 0.650 lift but the seat pressure is low enough to use on a 0.590 lift. I can get you springs, spring cups, & titanium retainers for $299.95. This spring kit should last, & give you great performance!
kjones@sdpc2000.com

m1key99WS6

iTrader: (1)

I've got a .589 lift cam and almost 50K miles on my 918's and don't experience any valve float issues, and shift over 6400+ rpm all of the time! I probably have over 300+ track passes 1/8th & 1/4 mile and drive about 120 miles a day (daily driver).

I would HIGHLY recommend the 918's for durability with that lift, but if you want even more piece of mind get a dual spring. I have no plans on changing mine

I also just notices you run a 216/220 cam which is exactly what I'm running with my setup. 216/220 .579/.589 114 +4 Comp.

99-LS1-SS

My opinion is I would rather have 2 springs instead of one. I like having the insurance of an extra spring. I want to buy a new motor eventually but I would hate if something broke and I was forced to park the car until I could buy a new motor. Double springs are like insurance in my opinion.

66ImpalaLT1

To counter mikey99WS6. I started having valve float with my 918's at around 20k miles with a T1 cam.

Just stating my experience with them.

jimmyblue

iTrader: (11)

If a dual spring are "just a little more than enough"
to keep valves from floating, than wouldn't half
of the closing force (while better than none)
still leave you with a good (bad) chance of some
valve-piston interference at higher RPM? Seems
like each of them would have to be capable of
handling the retraction in time, on its own, which
would be about a double-seat-pressure spring?

m1key99WS6

iTrader: (1)

I was going to replace them at like 20K like everyone recommended, but they don't float and I havn't lost any RWHP or ET with them yet. I would like to swap them out "only for the sake of testing" to see how much pressure they've lost over the period of 50K miles, and if my ET would improve but I havn't had the motivation to do that nor the time.

I'm a firm believer of "if it works don't F@#$ with it", and these spring definately work!

66ImpalaLT1

How old are your 918 springs? Mine are over 2 years old. They are not blue stripe because they're older than that fiasco.

m1key99WS6

iTrader: (1)

I bought mine about a year and 1/2 ago from thunder and they are the blue striped ones. I havn't slowed down any in the 1/4 with em yet, consistant 12.2's @ 113 and a couple 12.1's with a raceweight of 3750, I am however curious if I would gain anything by replacing them, but I doubt I would. If I had a spring tester (pressure) at the house I would pull one off and test em!