valve spring failure results...
Thread Starter
Launching!
Joined: Oct 2006
Posts: 202
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50,000...a little clean up,fresh heads and back on the road...
lucky it was at low rpm cruise,heard some racket,shut it off and coasted to the side of the road and towed it home...
time to plan on building something to replace the engine with anyhow...
lucky it was at low rpm cruise,heard some racket,shut it off and coasted to the side of the road and towed it home...
time to plan on building something to replace the engine with anyhow...
Thread Starter
Launching!
Joined: Oct 2006
Posts: 202
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since i am tossing out the 241 heads and going with something else,not sure yet what springs,don't know...
i have no fear of running comp single springs again...these broke and worked well up until then,so i will have to wait and see...
i have no fear of running comp single springs again...these broke and worked well up until then,so i will have to wait and see...
All parts work well up until they break, lol.
Thread Starter
Launching!
Joined: Oct 2006
Posts: 202
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all things considered,i got off light...a nifty set of those patriot heads are tops on my list right now...
Last edited by brokenfly; Mar 3, 2008 at 12:00 PM.
Thread Starter
Launching!
Joined: Oct 2006
Posts: 202
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it looks like comp is doing a good job of addressing the 918 snafu,so no,i have no problems with comp...
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Verdad Gallardo yeah the duals last a really long time, i have way over 20K on mine and they are still holding spring pressure. But my cam isnt too large, 232/236 .585 so it isnt too hard on them. I sure would not like to swap springs every 15K. Plus when a dual breaks you usualy have a good chance of the second spring saving your valve, piston, and head. Its a win win.
I'm surprised at the issues they have been having,
Hopefully they will get them all worked out.
And a set of Patroit heads complete are a great bang
for the buck.
you guys make is seem like it is the springs fault. It isn't parts get worn. 22,000 miles. common, that is a lot of life for a spring especially when it is rated for .600 lift and he was running right on the cusp. Don't reconsider your spring choices, just be smarter and check your springs.
you guys make is seem like it is the springs fault. It isn't parts get worn. 22,000 miles. common, that is a lot of life for a spring especially when it is rated for .600 lift and he was running right on the cusp. Don't reconsider your spring choices, just be smarter and check your springs.
You cant run 600 on the singles and expect 20k out of them.
I just had a conversation with a good buddy of mine, He has a 230/236 cam on a 112 and .551" lift, this cam has made 420 rwhp on a 2002 z28 m6 10 bolt car with NO UD pully, headers, cat back, tune and 72mm tb.
He has about 10-11k on the springs, they are older comp 918's with Ti retainers and even he will be checking them after this season. The cam lobes are not aggressive and he def hammers on it.
I think as long as people are conceious of whats happening, at least you stand a chance of not dropping a valve.
I had 987's in my LT1 and I had a valve hit #7 intake and the inner spring kept it up so it just bent and didnt shatter inside. Its a nice redundency the dual spring but singles can be fine too. Its just not a install and for get about it thing.
He has about 10-11k on the springs, they are older comp 918's with Ti retainers and even he will be checking them after this season. The cam lobes are not aggressive and he def hammers on it.
I think as long as people are conceious of whats happening, at least you stand a chance of not dropping a valve.
I had 987's in my LT1 and I had a valve hit #7 intake and the inner spring kept it up so it just bent and didnt shatter inside. Its a nice redundency the dual spring but singles can be fine too. Its just not a install and for get about it thing.
Launching!
Joined: Jun 2007
Posts: 212
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From: NC
There are plenty of other engine components that need warming up (pistons, etc.), but your springs are ready to go from the start.
Anyways, again those springs failed from a design flaw/manufacturing issue. The upper end coiled failed first. It could have actually run a little while like that without you noticing. What we call a soft failure. Then the body fractured and the valve dropped.
Launching!
Joined: Jun 2007
Posts: 212
Likes: 0
From: NC
you guys make is seem like it is the springs fault. It isn't parts get worn. 22,000 miles. common, that is a lot of life for a spring especially when it is rated for .600 lift and he was running right on the cusp. Don't reconsider your spring choices, just be smarter and check your springs.
Our original design for the 918 (now PAC-1218) was made so that the spring should last the life of your engine. It is not a high stress design. Made right, it will last that long.
Hell, I believe that if you call Comp they recommend checking them at 30k miles. Which is a number they just arbitrarily picked.
It is highly likely that even if he had checked his springs, he would have not found any problems. A crack can propagate at the speed of sound, through steel. And since I believe this is a manufacture/design defect, the typical "load loss before failure" would not have been present.
Just my 2 cents.
As for the original poster. I would swap PAC-1518s in and never have worry about them again. Or go to a Patriot dual.
Last edited by Yeahdoug; Mar 3, 2008 at 03:17 PM.
I would ask some basic questions on the original installation. Was the installed height measured, if so what was it? How close was the measured height to coil bind? Most installations I have seen are install and run, no measurement, no time to correctly set up, not much thought given to the valve spring setup and rocker arm geometry.
Staging Lane
Joined: Oct 2006
Posts: 83
Likes: 0
From: Iowa
Couple of basic questions regarding the spring failure:
1. How did you know there was a problem in the first place? In other words, what did you hear or feel that told you to check and see if one of the springs had failed?
2. When a valve spring fails like this, what other problems could have occured along with it?
1. How did you know there was a problem in the first place? In other words, what did you hear or feel that told you to check and see if one of the springs had failed?
2. When a valve spring fails like this, what other problems could have occured along with it?
I always run dual springs the last set was PRC Platinum duals and I changed them out after 43,000 miles..they were on a 233/233 .595/.595 112 cam and were still good when I changed them. I have a set of Patriot Gold duals on the engine now with 22,000 miles on them. Duals are the only way to go in my book.
TECH Addict
Joined: Nov 2005
Posts: 2,379
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I find it tough to believe that a properly designed spring will only last x amount of miles when many car manufacturers manage to use lesser designed springs to last 100k+ miles.
Is there something I'm missing here in aftermarket design? I know a LOT of us have bought used LSx cars and have only pushed it at it's hardest late in it's supposed life. I don't even think the previous owner of my car brought the revs up to 6k, let along 6500rpm repeatedly at a track prior to my cam install. I had almost 100k on my car before it saw hard track days.
It's funny to think that GM somehow makes their springs out of what? Unbreakium? Unobtainableaftermarktium?
I'd understand if you were bringing the spring to close to it's max lift or running 7krpm 99% of the time, but when you consider the life of an engine, most of it is spent UNDER 3k. This only further makes you wonder about the materials used and the engineering behind them.
Is there something I'm missing here in aftermarket design? I know a LOT of us have bought used LSx cars and have only pushed it at it's hardest late in it's supposed life. I don't even think the previous owner of my car brought the revs up to 6k, let along 6500rpm repeatedly at a track prior to my cam install. I had almost 100k on my car before it saw hard track days.
It's funny to think that GM somehow makes their springs out of what? Unbreakium? Unobtainableaftermarktium?
I'd understand if you were bringing the spring to close to it's max lift or running 7krpm 99% of the time, but when you consider the life of an engine, most of it is spent UNDER 3k. This only further makes you wonder about the materials used and the engineering behind them.