snappy28

If stock valves are such an issue how come these reputable shops don't have valve replacement listed in their head/cam packages?

http://www.katechengines.com/perform...hicles/c6-z06/

http://www.lingenfelter.com/engine-p...-ls7-2006-2013

http://www.mtiracing.com/C6-Z06-Engine-Upgrades.html

DON T.

Ugh!!! What!!

LFZ

Must not be a valve issue then if those think there isn't any..................................... ......

'06 Quicksilver Z06

Well katech has a working relationship with GM, undoubtedly one of it's larger clients.

I want to preface what I point to below, by saying that any shop can have a failure. Those advocating either valve.

But for your perusal, and with regard to the other two shops you mention.

http://forums.corvetteforum.com/c6-z...-hard-dea.html

http://forums.corvetteforum.com/c6-z...376-525-a.html

Katech_Zach

Our use of the factory valves is based on our experience and research, not customer relationships. To imply that we are for some reason selecting an "inferior valve" based on protecting one customer relationship (GM) rather than what's best for the package (and the majority of our customers) would be incorrect. Our research and experience has shown that it's a guide machining problem, not a valve problem. If we did not feel comfortable with the stock valves in a given application we would not install them in our warrantied packages.

'06 Quicksilver Z06

I didn't "imply" anything of the sort, but only stated a point of fact, and that is that your company does maintain a working relationship with General Motors. In other words, GM is one if your clients.

Or is that not true?

Because if it is, then every man in here can infer what, if anything that would mean to him.

Al Green

Thank you Jason, had Richie at Able do my heads. They found 4 out of GM specs, hope all is sound with my heads and I can enjoy a wonderful car. A side note only the heads was replaced. Thanks to Richie and the crew at Able.

z0sicktanner

Well then why use Richard at wcch if hes that incompetent not to be able to find a machining problem why would you want him to do your heads? you would think Richard would have found that to be the problem. it isn't, and anyone can call to comfirm it with him. I mean really Richard does more ls heads than anyone I know of. if it was a machining issue Richard would have found that very quicky

z0sicktanner

it's true and lingenfelter has ties as well...

Katech_Zach

The OP asked why these companies use OEM valves if there is a valve issue. Your first response and first sentence was that GM is our largest client. I don't know how to connect those two statements other than an implication that our choice is somehow based on a conspiracy theory to protect our (assumed) biggest customer rather than our own free choice.

'06 Quicksilver Z06

Jason, you accused me of "implying that you were using an "inferior valve" because of your relationship with GM.

I never said anything at all about any "inferior valve".

I never said anything at all as to the quality, one way or another, of the valves you use in your packages, inferior, superior or otherwise.

z0sicktanner

because thats the problem

wjnjr

Hey Jason,

What exactly is the valve guide machining problem you guys have found?

Mark2009

When all else fails, construct a conspiracy theory!

Hey, look everybody -- Quick thinks the OEM exhaust valve is just fine! All this time we've simply misunderstood!

Katech_Zach

That was the implication that I drew from reading your post. It's possible that others have too. Correct, you never used those words, but your response leaves the impression that there is a conspiracy. If you had a different motive for quickly mentioning that GM is our biggest customer when the OP asked why OEM valves were being used I would be interested in hearing it.

Quick, don't get me wrong, I still luv ya buddy.

z0sicktanner

these three have had valve failure using the oem valve. take it for what it's worth

z0sicktanner

Mark I think I helped a lot of ppl with my conspiracy theory. isn't that the reason you checked your heads after watching the vids I posted up?..so far I'm shoting 100% on my theory on how many cars would turn up so laugh all you want. how those guides in your heads? lingenfelter has strong ties to gm mybe you should look

Katech_Zach

GM has stated that there was a machining error on 2009-2011 LS7s (LS9's too but I'm not sure if GM specified that) that caused the valve guide to be machined non-concentric to the valve seat. We have found that this rapidly accelerates valve guide wear. The valve rocks in the guide and wears it out in an hourglass shape. The more it rocks, the more it wears in that manner. So far we've caught some very bad wear before the valve breaks, but if left untreated, the rocking in the guide is so severe that it fatigues the head of the valve until it fails. Every time the valve opens and closes its getting bent slightly in a different direction, working the stem around the base of the valve head.

Now, if I was involved in a cover-up with GM I wouldn't tell you the following. We recently saw high valve guide wear in 2007s and 2008s, so I'm not so sure that this is captured only in 2009-2011s.

A recent build, which I will post about soon, had massive (and I mean massive) intake guide wear. We caught it just in time. Now why would this be happening if it's just a defective exhaust valve? It's because it's not. It's a guide machining problem which could be on the intake OR exhaust OR both.

'06 Quicksilver Z06

For all myself or anyone else knows, as a result of that relationship, you could be privy to information which the other vendors are not.

Why did you immediately assume, that because I pointed out that relationship, that I was necessarily implying that you were using an "inferior valve" when I said nothing of the sort in my response to him?

'06 Quicksilver Z06

A yes or no will do, and without revealing any sensitive information, but are you currently or formerly a GM engineer, or have or have had any professional ties with GM?

You either can or cannot answer that truthfully with a "No".