Comp 918 failure caused #6 piston to disenegrate :(

[11 6.2]

Well ive never heard the 20,000 mile thing before, i may def think bout when i eventually cam the 6.0.. Andrew i start it and drive it.
Thanks bryan!

[oleshifty]

I'd bet that's the reason it broke. Aftermarket valve springs are more brittle cold, it's a downside to having performance springs, the reason better springs aren't used from the factory. You're supposed to let them warm up before putting any kind of extra load on them to avoid stuff from breaking. Not saying they'll always break, but in this case, it did.

[Frenchy]

The reasoning behind the 20000 mile deal is that they are a stiffer spring. This extra stiffness creates more heat. Excessive heat takes the spring out of spring steel. So basically you're left with coiled brittle steel. Duals are worse for it because they are stiffer as an assembly but the springs themselves are actually weaker. Now I seen a company (I wanna say PAC) advertising their springs guaranteed for 100000 miles, so maybe the companies are finally figuring out there's guys running monster cammed DD's now and need the durability.

[CHEVROLADE]

them comp 918s suck...that happened to my buddy,he caught it early though while idling 1 spring broke and they were the new batch as well lol

[bangbangskeetskeet]

The reasoning behind the 20000 mile deal is that they are a stiffer spring. This extra stiffness creates more heat. Excessive heat takes the spring out of spring steel. So basically you're left with coiled brittle steel. Duals are worse for it because they are stiffer as an assembly but the springs themselves are actually weaker. Now I seen a company (I wanna say PAC) advertising their springs guaranteed for 100000 miles, so maybe the companies are finally figuring out there's guys running monster cammed DD's now and need the durability.

One of the guys at TR told me that he had patriot golds I'm his car with a fairly large lift cam...~.600" lift...and that he has pit around 50,000 miles on the springs. And not just 50k of conservative driving.

[PitchBlackC3]

Glad I went with the PAC 1518s when I got my springs for the 243s. Threads like this seem to pop up often, that's why I made the choice to stay away from the 918s.

[11 6.2]

Ya im really leanin towards leavin the LQ9 just boltons for now and then maybe in the future doin alot of investigatin and findin a company that guarentees there springs like ur talkin bout devon.. But for now im really wonderin how a full bolt on 6.0 is gonna act with my 3400 stall and maybe some spray.lol

[DBRODS]

I will never install another set of single behive springs. If you loose one you more than likely loose a motor. The last set of the Patriots dual 650's only lasted me about 10k miles before i started seeing valve float. Good thing is with the duals if one breaks you usually don't drop a valve and you can catch it. And theres really no such thing as too much spring pressure. We will see how long the new 675's last..

[bangbangskeetskeet]

I will never install another set of single behive springs. If you loose one you more than likely loose a motor. The last set of the Patriots dual 650's only lasted me about 10k miles before i started seeing valve float. Good thing is with the duals if one breaks you usually don't drop a valve and you can catch it. And theres really no such thing as too much spring pressure. We will see how long the new 675's last..

Which springs did you go with Jon?
I went with the patriot extremes. .660 lift should be good for a while.

[PitchBlackC3]

OP,
How much lift on your cam?