Cruncher

If his "sample size" isn't large enough then your accumulated numbers don't mean anything (other than a good read). To wit: I didn't report my vehicle info, probably just like other people, including non-Forum owners. By the way, what is an adequate sample size for you? Do you know what the universe is? I do statistical sampling and your statement of not having a large enough sample size is invalid and unproven. I have various programs that determine sample size, sample selection, sample results, correlation, etc.

racebum

you're looking at the wrong variable. mileage isn't accurate when it comes to fatigue cycles. someone could be idling in traffic or cruising down the freeway, engine doesn't know the difference

track use with sustained high rpm driving is much MUCH harder on valve springs than running it down a public highway

there really is no measurable way to gauge failure as people often don't keep track of how they put the miles on the car

skyavonee

I thought you were "finished with this bull". I can see my earlier response to your previous nonsense hurt your feelings, hence your need to try to prove me wrong later. Forum member halp and I have a history in this thread; read back and see for yourself the multiple back-and-forths between us. My latest response to him was meant in a jovial manner (hence the excessive exclamation points and the big grin), as I merely took his arguments against my study and turned them back on him. I'm sure he was aware of this, even though you weren't.

skyavonee

...which is one of the reasons why I never bothered to gather the mileage info.

NBM LS1 M6

My '02 Z06 had just over 50K miles on it when one of the valve springs cut loose. I suspect the previous owner never drove the car very hard. I bought it with 36K.

However, perhaps I loosened it up a bit running a tight autox course in 1st gear only. In any event, I am thankful that the repairs were limited to replacing all valve springs.

NBM LS1 M6

halp

Sky: I never take offense to your comments. As I have stated many times I find this thread very interesting. I was the one who said that it was important enough to be a sticky. I always check to see if new info is added. As I said before, it is to bad that more did not report mileage, maybe future ones will.

skyavonee

I finally got around to uploading the latest data. I'm still hoping to get VIN info from user Evil Oil Apologist, who was active on the forum as recent as late January, and whose 2003 suffered two valve spring failures.

Wire5150

Well, heres another to add to your research just this past sat 05/18 drove a mere 3 miles to the corner store to get gas and a cup of coffee, jumped back in started it and all was fine.

Drove 1/4 mile made a turn and drove 25mph in a 20 zone for another 1/4 mile or so, pressed in the clutch and stalled. restarted heard a tapping sound and immediately turned it off called a tow.

Did some research on here and called the shop where it happen to be towed to and told them not to attempt to start it cause I knew by what I read on here it was a valve spring. Towed it away to the vette performance shop close that has a awesome reputation for fast ****.

Told them the story and that it didnt set the typical 300 DTC, they agreed broken valve spring. Later that day got a call after leak down test and was told yes, it was a valve spring #6 went up there and took the pic of it below, received another call after head removal, no piston nor block damage.

Totally stock, never has seen rain, kept in garage, motor has been cleaned a mere 4-6 times in its life, oil changed every 3000 miles regardless. It is now going thru head work, total valve job, tsunami cam/dual valve kit, headers air intake etc. sucks but, gonna do it.................wanted to keep it stock and clean.

2002 Z06
Last 4 of the VIN 5180
77,000 Not a daily driver and rarely driven hard nor never hit the tracks. Pic below................ friggin chevy, why cant they get it and understand the issues with the valve opportunities they have. They did something with the C6 issues from what I read on here.

halp

Told them the story and that it didnt set the typical 300 DTC, they agreed broken valve spring. Later that day got a call after leak down test and was told yes, it was a valve spring #6 went up there and took the pic of it below, received another call after head removal, no piston nor block damage.

Why did they remove the head? From your pic, the valve did not drop so you should have not had any damage. Looks like you could have just replaced the springs and been done with it.

Good luck with your mods.

Another 50,000 mile plus failure.

Wire5150

Told them to do it by request and as preventative maint these guys handle these cars all the time. Need to done with the whole damned thing so I dont have to receive issues with it later down the road again. The mods are gonna pump it up another 90-125hp we'll see on the Dyno by tomarrow.

Also. I feel just as probably everyone else on here the issues dont reside with just mere milage alone, that has been random up and down the scale. Its the fact that the springs are the failing and it could be the valve port itself or head that is the issue. GM found that the machining of the heads on the C6 by a 3rd party at factory install was the issue so, why not with the C5 as well.

ZeeOSix

On the C5, it's really just the springs. Heads, etc are fine, unlike on the C6 fiasco. Use of the car (ie, not getting on it hard until the oil is near full operational temp) probably has more to do with why some springs fail quicker than others.

Z06CE

I purchased a 2004 Z06 Z16 3 months ago with 48600 miles. The last six VIN is 132277. I'm considering replacing the springs with PAC 1518's, but on the fence though.
I have a related question---- When replacing the valve springs--- do you guys think the rocker trunion should be retrofitted?

Trash

I'm of the opinion the trunion doesn't need to be retrofitted. I'd stick to the simple fix of springs and be done with it. Once you start throwing other parts at it you're needlessly opening up the variable pot.

dart.deanda

I am doing mine. Why not, the rockers are off? Supposedly they break apart. I don't want to go back into this engine for nuthin (I am one of the casualties...). $135 from Summit for the kit.

Trash

I have not heard of any issues with LS-6 rockers or trunions. The LS-7 had some issues with the needle bearings falling out which was a TSB if I'm not mistaken.

If you search for valve spring issues on this forum you will find many hits. Search for LS-6 trunion issues and it will come up virtually empty. Having said that feel free to change them if you want. I've got no problem with that, I just don't feel it's necessary with the stock set up.

dart.deanda

I see a lot of hits on this forum, zo6vette.com, and others for C5s. All the way back to 2004. I'm pretty sure any of them can be impacted by this. Sure if it ain't broke... But, if there is a trend, I guess it's just peace of mind for me at this time. I'm replacing the oil pressure sensor too. Not leaking, but they do, and the manifold is off (other reasons). I am doing the LCM5 steering wheel lock repair as well. There are a lot of things that I am just not willing to take a chance on any more. Personal preference I guess. Good luck to all.

Trash

Interesting. I found zero hits regarding LS6 trunion issues.

Z06CE

I was on the site where I saw the trunion issue. http://www.corvsport.com/Corvette/C5...monIssues.html
where they list common problems and the bearings were a issue on some cars.
What to you think about the valve springs for 2004 Z16 Z06 corvette Vin 132277

skyavonee

I think they're perfectly fine, and it would be a waste of time and money to replace them. Look at the numbers - only 4 failures have been reported by 2004 cars, compared to 91 for 2002, and 48 for 2003. The problem was fixed some time in 2003.