Coach62

At $35 a valve I see no reason NOT to change them. If the guide is worn, the valve will have been subject to undue stresses from closing while not square in the opening.

At less than $300 to put new, post 2008 valves in as VERY cheap insurance.

Mark2009

If the guide was badly worn, then yes. I was speaking mainly of a post-rebuild scenario where you were starting with new valves, watching the guide for wear, and nipping it in the bud, so to speak... or had mostly minimal wear in late model heads.

And on that topic (future wear) there seem to be two pretty much gold standard but not necessarily guaranteed options to avoid it (regardless of valve used):
.

MTPZ06

I have another 32 months on my GMPP and then I'm definately doing a head refresh and maybe a mild smog cam. IMO, I think the valves to watch are the Ferrea Lightweight Hollow Stem Valves. I have over two years to keep an eye on what happens with LS7 valvetrain upgrades.

vvlf

Stiff and light is good, but with bad head geometry, stiff and light will still fail. People should first check their heads setup/geometry, then address the guides and valves.

Dirty Howie

I relied on Richard at WCCH who says he know of NO failures with the SS valve/bronze guide/dual spring set up that he has been doing for many years. Just take a look at all the vendors here who use WCCH for their customers. Ryne at CMS runs the same setup in his H/C Z06 and advised me strongly many times to get it done when we were on the track together. No brainer as far a I'm concerned.

I have 15K miles and 8 track days on my WCCH setup. Another track day in 2 weeks


DH

Coach62

Thanks everyone. Howie, have you rechecked the guides - wiggle test since installing?

Don't you have a pretty high mileage car, like over 100K on everything but your heads? That gives a lot of confidence in the durability of these cars.

It's a tough call, both sides make a good case. I did chat with Jason at Katech and he says to go with the bronze guides and stock valves.

Dirty Howie

135K miles now. But the first motor blew up with 87K. Of course, it had the stock valves


DH

propain

A car that runs for 80K miles before blowing up on stock everything and heavy track use sounds about right to me. How that is a GM defect I have no idea. Sounds like a really good run to me.

20K on the "Fix" is hardly saying anything. His stock valve train setup ran 4X that amount of abuse before blowing up. That is also the case with most coming out of WCCH. Most have very little miles so the test data is slim. Just like the stock failures it will take years before we start seeing problems. In my opinion sooner than later with the data I have seen. There have been failures BTW with SS/Bronze and we recently had a thread with WCCH heads and the valve stem beat up pretty bad. It was pulled but it didn't go unnoticed to many before it was.

Choice is a beautiful thing and you should do whatever makes you feel most comfortable. But to me if I am going to look for advice I would soon listen to someone who builds race engines rather than someone who just does heads. Katech uses WCCH to do their head work for their race engines and they do not go with Richards recommendation. I don't know about you but I have to ask myself why that is.

Good luck with whatever you choose.

Coach62

That's the way I'm leaning right now, pretty strongly. I still have an open mind, but to my knowledge Katech is the only one that's done any real testing.

'06 Quicksilver Z06

You know Howie, when I look at your case, it reinforces the fact that when it comes to one of these LS7s eating a stock valve, it's purely luck of the draw. Or better put, when we see examples of cars dropping stock exhaust valves, with considerably fewer miles than what yours had, well it then looks like a matter of "when" as opposed to "if".

You made it to over 80K miles before having one of the stock valves decided to take a shot at putting a hole into your engine block, and then a hole into your wallet.

There have been several in here who weren't nearly as lucky when it came to mileage before one of the stock exhaust valves let loose.

Coach, you have a lot of questions, and I want you to take a look at something.

http://forums.corvetteforum.com/c6-z...post1581584713

Now, you are modifying your car, with a cam I believe?????

Take a look at that stock listing, and then take a look at the modified listing.

To give you an idea, over time, I have found somewhere around 40 cases of stock exhaust valve failure in "cammed" and "modded" cars in here where the exhaust valves were left stock. In fact, I just found another one today on nothing more than a token perusal for another example of a stock dropped valve. http://forums.corvetteforum.com/c6-p...post1584069123

And then one more which I recall from a prior exchange with a forum member from a few months back, and which is not included on the listing I referred you to:
http://forums.corvetteforum.com/c6-z...post1583796510


When you look at the stock listing, be advised, that what was often referred to as a "broken valve spring" back then, was all that the owner had to go by, as the early failures which occurred under warranty, the owner would be given this "reason" after the car had either gone back to Bowling Green, as the early failures were managed, or back to the dealership.

The point here, is that the owner, wouldn't know just what condition the "valve spring" was in, as GM simply replaced a lot of those motors, under warranty, and gave the owner that particular reason as a cause of failure.

You have also heard that it is the "valve guides" and not the valves themselves.

Well, do a little research, and see how many cars in here you can find, which failed a stock exhaust valve, and which also gives any description whatsoever of what condition the valve guides were in.

You won't find many, you may find one out of all of the instances of stock exhaust valve failure described in here, because typically when one of these motors eats a stock exhaust valve, no one knows if the valve guides were worn or not, because the resulting carnage is so bad.

Now a lot of times, we say that mods and tracking lead to the failure.

But if I am following your prior posts, you are in fact modding your car, for power. And this is why I suggested that you take a look at the number of valve failures which have occurred in both stock and modified cars. Many, not all, but many of which, are listed in my response to Bill, in that linked to thread.

Also, bear in mind, that the stock setup, found in any LS7 equipped Z06, was indeed "tested" before it hit the market. But look at the descriptions of exhaust valve failures in stock LS7s, both on that listing I made several months ago, and before the number of cases simply became too many, and too frequent, for any one man to keep current, and the descriptions of stock valve failure in here since I made that reply to Bill.

Furthermore, keep in mind that those failures are simply the ones which have happened to forum members in here, and does not take into account stock failures which occurred outside of here, in the "tested" stock LS7 valve train setup.

Talk to Howie, about the at least 7 or 8 LS7 failures that he is personally familiar with, or outright witnessed. Talk to Bill about the nearly 10 failures he knows about and outright witnessed.

Most, if not all, involving the stock valves.

Finally, take a look at the following. It is an excerpt from "The Registry", and includes failures which occurred around the time of it's existence, which would have been around spring/summer of 2012, until now.

Granted, a motor can fail from a number of things, and addressing the valve train is simply an attempt to minimize the chances of one of them.

But if you can read the prior descriptions of failure in stock and modified cars I pointed you to in my response to Bill, as well as the following descriptions of failure over the past 11-12 months or so, in cars belonging to forum members like yourself, many of which were confirmed or strongly suspected to have been due to a stock exhaust valve failure, and still feel comfortable using stock exhaust valves in your build, well then that is your option, and I wish you the best of luck with it.

Cars belonging to forum members which have suffered engine failures since around 6/12.

I added this section to the listing, for further informational purposes, and will be updating it from time to time along with the rest of the listing. You are free to read the descriptions for a perspective on which ones were stock exhaust valve related.

I also include at least one example of failure of the stock titanium intake valves, as there is talk of using titanium on the exhaust side. The spontaneous fractures of the titanium intake valves mentioned in those cars in here, at least says to me, that such a fracture could occur on the exhaust side as well, were the owner using titanium there.

1. CGZ06 2009 stock 34,670 miles
2. Cyclone09Z06 2009 stock 18,200 miles
3. Jackal 2006 56,000 miles cam only
4. jmurf28 Stock 2006, 13,555 miles[/B]
5. fmcockc 39,000 miles failed on track

6. Gary Glasser 2006 Z06, dropped a valve at 40k miles
7. jad568 2007 45,000 miles failed while being backed out of parking lot
8. AreOhBeeC6Z 29,000 miles, bolt ons
9. Daniel Hoffele 2007 49K miles CAI, Catback, stock tune.
10. philpacs 2006, 30K miles

11. turbo50mike 2007 no prior mention of the incident that I can find before the hyperlinked thread.
12.*DaWizard
13.*kawaiilaosboy
14. z0silk 2007 55,000 miles engine replaced under warranty after dropped valve.
15. Vividz06 '07 30K miles 2 hrs on a track 20k later.

16. boost2na '09 17,300 miles.
17. dsharkman '07 17,775 miles. Billy Boat Exhaust and a Halltech Killer Bee intake.
18. jph331 '07 86,000 miles. Lost a valve into the #1 cylinder. Failure was due to valve trouble, but owner doesn't know if it was an exhaust or intake.
19. Stanger383 '07 20,000 miles.

I still believe though, that your best bet would be to follow the advice of the shop which you say that you have selected for your build, which I believe you said was Redline Motorsports, as opposed to relying on the sentiments of us on the forum with regard to this matter.

Ask Redline what kind of success they have had, and why they recommend what they recommend.

Again, best wishes, and let us know how things turn out.

Dirty Howie

Nice addition to the list Ricky. I'm sure many members refer to it before making their decision on what to do.


DH

Dirty Howie

It was GM that decided it wasn't a good enough run. I didn't hold a gun to their head. They replaced my motor because it failed and should not have ......... IN THEIR OPINION !!

As an analogy, ............. if I went to my internist (responsible for my whole engine) and he sends me to a proctologist (rear end, not head specialist), I will certainly follow the advise of my proctologist

PS: Glad to see you back !!!


DH

propain

Yes, its called a warranty. Lucky for you you had one and lucky for you they didn't hold your track use against you.


...and then the results of what the proctologist reccomend come out and what the internist told you to do is turned out to be right, not the "specialist". Then I wouldn't be going to that proctologist anymore.


I've been posting here and there, I have just been away on vaca so not as much... thanks though.

Coach62

Quicksilver, thank you for that response. Like I said, I'm leaning but my mind isn't 100% made up. I'm obviously not trying to argue here, just trying to have a good discussion so we can all make up our own minds on this. I do plan on talking to both WCCH and Redline about this later this week.

It would be fair to say that there are few, if any known failures of the WCCH heads with SS valves. But it would also be fair to say that there hasn't been a lot of time to fully evaluate them either, right?

We could say the same thing about the stock valves with bronze guides. Do you, or Bill know of many tracked cars with stock valves and bronze guides?

It does bring up a few things for discussion.

1. The SS valve is obviously a time tested valve and can take a lot of abuse, but GM obviously felt it was important to go the sodium filled route.
2. The new sodium filled valves would be the most recent production, which have had fewer failures, correct?

On the other hand, I wonder that if the bronze guides were the answer, why didn't GM switch to them after some failures surfaced.

Last, I think it's important to consider that the LS6 had hollow sodium valves with steel guides and they had very reliable service. I think that says a lot, doesn't it?

'06 Quicksilver Z06

You are welcome Coach.

I'd say to get your best answer on that, you'd be better off following through on what you say your plan is above, with regard to asking them directly.

But also to your point, I would think paramount in the decision making process, would be just how much time is "enough", and how many examples "enough" in order for one to be comfortable.

That answer is of course going to vary from one of us to the next, much as it does the other way around.

In other words, how many stock exhaust valve failures does one have to see in order to opt for something else?

How many failures are enough?

That threshold is going to vary from one of us to the next.

Not to be flippant about it, but that's just how I see it.


Cars in here, from among that particular subgroup, are going to be in even smaller number than the prior group you mentioned.

Considerably smaller.

So if small sample size and real world duration in the hands of average owners are concerns for you with regard to the former group, then it certainly doesn't seem that concern would get any better in terms of it's extent with the group you mention above in bold, as that number is even considerably smaller.

Fewer cars were made too.

C6 Z06 production in 2010, for example, was 518 units. In 2011, it was 906. In 2012 it was just 478 cars.

So if you have fewer cars, it would follow that there are fewer cars to fail.

However; it can certainly be pointed out, that it is still a matter of concern, the fact that the failures do indeed continue, even in those later models where production numbers were small.

For reference, in 2006, there were 6,272 Z06s built. In 2007, there were 8,179 C6 Z06s built. In '08 there were 7,731.

So even though the number of cars has dropped dramatically in later years, we still see the issue of outright valve failure, not just simply worn guides, mind you, though we see those too, but I'm talking about outright valve failure, showing up in later year models. 2009 models for example.

That's troubling.

In your research of this matter, or at least in what you say is your planned research, a couple of things will likely be pointed out to you with regard to that.

The LS6 makes considerably less power than does the LS7, and the LS6 valve, albeit still hollow stemmed and sodium filled, is not the same valve as that used in the LS7.

Coach62

Thanks, but you were supposed to make this decision easier for me LOL...

I'll follow through by talking to WCCH and Redline in the next few days and make my decision.

To your knowledge, has anyone done the wiggle test or examined a set of WCCH heads after 20K or so miles?

Coach62

I'm not sure how relevant that point is. HP/CI displacement is pretty similar. I know it's fewer BTU's (measurement of heat) exiting the exhaust
That's the only way that could be relevant.

We could also point out that there are TONS of cammed LS6's with stock valvetrain (except springs) that hold up very well. My LS6 actually put out about 500 HP with heads, cam, bolt ons.

propain

All good points. Time will tell for sure on the SS/Bronze config. One thing I believe we have learned however is if you are going to run that config do not go with the dual springs as previously recommended (Or possibly still recommended by WCCH) The Katech spintron test showed the beehives are way more stable in that config.

One thing I disagree on though is the valve failing spontaneously and not due to guide wear. That is a ridiculous speculation based on zero evidence. The lack of evidence being the only evidence post failure in support of it. On the contrary the evidence is strongly in support of the valve failing due to guide wear. The current paranoia to do the head work is entirely based on guide wear. Not "OMG get those horrible spontaneously combusting valves that break for no reason out of your car!" To suggest otherwise is ignoring the 800lb gorilla in the room.

The list while nice as well means nothing at this point. It only serves as sensationalism. We know there is a problem and we have narrowed it down to the problem. The majority are Guide wear. Showing how many cars that have failed modded or stock, tracked or garage queens only supports that if you don't fix or monitor your heads you stand a chance at catastrophic failure. Not, a supporting argument to demonize the stock valves.


Thank you for the discussion Coach and keeping it civil and on point. From this point on the discussion will become very circular so ill be on my way. Good luck again with whatever decision you make.

propain

Yes, at 20K miles a WCCH Bronze/SS showed wear on a daily driver with no track use. I believe he is now switching back to iron guides.

'06 Quicksilver Z06

Yes, forum member 240sx2jz, posted up this thread.

He says who did the original work on the heads, these heads did have SS valves and bronze guides in them. He also lists his mileage.

http://forums.corvetteforum.com/c6-z...nspection.html

You may also want to take a look at what Darin Morgan has to say about bronze.

http://forums.corvetteforum.com/c6-z...post1582219212