ConfusedGarage

I am one of those running wcch heads with new oem exhaust valves and katech ti mo intake valves. My car has been over 500 rwhp since day 2 and while my guides were in spec at 17k mi I still feel they are suspect in these failures. The wcch guide is longer and we havent seen one failure with anyone using them on SS valves or oems, which is why I feel the oem guide is suspect, though I realize its a smaller sample. If someone like Painrace (or any other racer pushing their car above what 99% of us can do on a track) keeps his katech motor together with oem valves, then I feel quite confident that ill be fine. I drive the snot out of my car and hit yhr rev limiter daily and have been fine. 80 of my 115 drag passes were on my street tires where im on the limiter in3rd at 133 tje last 30 ft or so on my taller 345s. I am hard on it is what im saying.

Bottom line, check your guides guys. The valve you use is much less important.

0C_Williams@RPM

Call me - I'd be more than happy to discuss the issues and the various options - I'm a forum vendor and have done many of these.

0C_Williams@RPM

Guide Options ( that I use)

Guides

CHE Bronze Valve Guides - http://www.cheprecision.com/html/guides.html

Ferrera Bronze Valve Guides
http://www.ferrea.com/Chevrolet-Valve-Guides/p33822


Valves - Stainless Steel

Ferrera
http://www.ferrea.com/Chevrolet-Engine-Valves/p34266

Rev

http://www.revvalves.com

Supertech

http://www.supertechperformance.com/products?id=121

H82BFST

So.... are your lifters holding up guys?

Mark2009

Everyone here is too wound up pushing the exhaust valve du jour to worry about the lifters

But personally I think Brian Tooley has something very interesting on that front... if I were shopping lifters, I'd be talking to him. Low leakdown lifters, or something like that. He'll know. Supposed to be high quality hand fitted... something obviously lacking in OEM LS7 valvetrains these days.
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Mark2009

CHE's brochure describes a very interesting valve guide. Without really knowing what the others offer, theirs sound very very good.

I keep warming up to WCCH's approach of installing a slightly longer guide; other than a slight airflow nick this certainly can't hurt, it might help dissipate heat with an OEM valve, and if the theory of a flexing exhaust valve stem creating the lower guide wear were to be true then a longer guide could help quell that flexing. Sounds like a lot of potential upside with essentially no downside (except for the dyno crowd).

Charlie @ RPM has contributed facts and knowledge to several of these threads. Hard to go wrong with that

Mark2009

Since we're deep into the topic here, who knows why the GM engineers specified a sodium filled exhaust valve for the LS7?




Yes, I know.

'06 Quicksilver Z06

On that we can agree.

CHE makes very fine products, their rocker trunion upgrade is in my own car, along with WCCH's "longer guides" and Brian Tooley's springs.

You mention Charlie above, and if one looks closely in this thread, they will see what valves he has been using, and with good results in his heads since 2007. Somewhere around 6 years. I'd say that is a decent amount of time to get a feel for what does and does not work when it comes to the management of the concerns of the original poster and others.

http://forums.corvetteforum.com/c6-z...e-to-come.html

If one is interested in looking more into valve materials, the two links were referenced in here earlier by another poster.

http://www.precisionenginetech.com/t...esigns-part-1/

http://www.precisionenginetech.com/t...esigns-part-2/

But irrespective of why GM's engineers chose sodium filled stainless valves for the LS7, two facts remain.

1. The number of reported failures in here of those valves, is totally unacceptable, regardless of reason why they were selected.

2. The original poster of this thread, quite possibly having similar sentiment leading to real concerns, has expressed an interest in finding out what alternatives there are for him.

Mark2009

Quick, I read your two links. I will put you down as "No, I don't know why GM engineers chose a sodium filled hollow exhaust valve for the LS7."

Thanks for contributing

CHE makes fine valve guides for the LS7 because of, among other things, their claimed heat transfer capability; something that is not really needed with a non-sodium valve, but you knew that, right?

Oh, well, maybe not . . . . .
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'06 Quicksilver Z06

Actually, I'll do you one better.

I don't especially care why GM's engineers selected as they did, or more accurately, I don't care if you think you know why they selected as they did.

That which you somehow seem to take pride in being privy to, I could not give a $*** about.

Why?

Because whatever reason they had for choosing as they did, there STILL have been entirely too many failures as a result of that choice.

Mark2009

How can you give advice with no answers?

If you claim that others -- such as GM engineers -- have done wrong, should you not be able to describe where they went wrong? If not, how can your solution have any credibility?

You now say that GM engineers chose wrong. What is your evidence that it is their fault, rather than some QC or other issue beyond their control?

And, for the third time, exactly how many failures has there been?
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'06 Quicksilver Z06

Man, are you really this thick?

Have you not seen the several failures of these valves in here?

Who the hell cares why GM engineers selected these valves? They are failing and putting people at a financial disadvantage.

The "evidence" is in the several instances of failure we have already witnessed in here.

If it was QC, well then why has it gone on since 2005?

They made a bad selection for this application.

Seriously, I have gone back and forth with you on this matter for a long time now, and some of what you say is completely out of left field.

Mark2009

"That" is knowledge. Your valuation of it is noted.

'06 Quicksilver Z06

Exactly more than there should have been.

Or perhaps you believe that the "exact" number of failures, seen in this forum and outside of it, is acceptable?

Do you? :

But if you want a number between 1 and 30,000, well then perhaps you should ask GM, the architects of this mess.

Oh, that's right, I forgot. They don't even know. They only know how many they have covered under warranty.

In fact, the supposed "mis machined" heads, they don't even know which cars those are in, so they cannot give a VIN range.


Knowledge which from a practical standpoint, is completely worthless. And that is my "exact" valuation of it.

Go ask the guy with the fresh hole in his engine block if he gives a damn why GM's engineers selected these valves.

Mark2009

I see. You are smarter, at least in retrospect, than the GM engineers that designed the LS7 valvetrain/combustion chamber. You don't know why they chose the valve they did, but you are sure that they were wrong, and that your choice is better. Yet I am completely out of left field. Noted.

'06 Quicksilver Z06

All that I can tell you with 100% accuracy, is that I'm smarter than you.

You were close. I fixed it for you with the part in bold.

Mark2009

Ah yes, emotion fuels your argument. Valve broke, valve bad. Just imagine if we applied your logic to other vehicle components. Tire flat, tire bad.

We'd all be driving around on solid stainless steel tires

'06 Quicksilver Z06

As I said earlier, I'm smarter than you. As such, I can recognize a lousy analogy when I see one. And your "flat tire" analogy, is absurd.

So if we used your logic, you would argue that we should be running rubber exhaust valves.

z0sicktanner

Mark2009

Unfortunately your posts, and your posse, indicate otherwise.

My logic, as per my tire example, indicates that things can fail due to external factors unrelated to any direct design or engineering defect. Your logic allows for none of that.
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