dr_whigham

Mines an 09... 36k miles. Yeah, I'm definitely worried. If the "wiggle test" is 500+- out of pocket, I may just do it. It's already going to be there for recalls anyway.

SHM

Ok...Yeah...I can see why you're so concerned. To be honest, I still am worried, too. I mean, even if GM replaces my engine, I'll loose a 'number matching' engine (if this sort of thing is still important on modern cars) and that could affect the value of the car, too. Plus, I just don't want to go through the action of a dropped valve, especially at speed. I'm not a mechanical engineer or technician. My background is electrical/electronics. So I don't work in the field. All I can do is try to do what seems reasonable without head removal and disassembly. I thought any TI or other materials showing up in the oil after 8Kmi would give me cause to go back to the service adviser, then work up through the chain from there.

I have read in articles where heads failing the wiggle test pass with using some sort of fancy laser 3D bore measuring tool. But, I don't understand the specifics on it, to be honest. I'm still trying to wrap my head around a lot of the high end technical specifics mentioned on the forums.

Anyway, anyone else here who'd like to beat me up on this, please feel free. I'm hear to learn.

grcor

The only time you need a super accurate measurement is when you are under warranty and you want GM to pickup the repair. If you have no warranty, you simple remove the valve cover and grab each valve spring/retainer and rock them back and forth. If you see the valve stem move, your guides are bad.

bd4airman11

MTPZ06

By no means am I beating you up, which why I said your plan is fine for you because you have a warranty. My comments were directed towards those who do not. You may however want to have a plan of action in place prior to your warranty running out. I did...as I have a GMPP that expires in April of this year.

Late last year I took my car to AHP for a guide inspection...and my '09 C6Z w/ 15,000 easy street miles failed miserably with 14/16 valve guides beyond GM service limits, and the remaining 2 right at service limits. I already knew precisely what my plan of action was if I were to receive results such as those...and I had a good (or maybe bad) feeling that would be the case unfortunately.

So that's my only advice to you...your current methodology is something I wouldn't advise to those out of warranty that want to keep an eye on their valvetrain. As far internal engine components, oil analysis is certainly a good thing to do. But for the valve guides, its real simple to just pull the valve covers and get a firsthand look.

LawrenceFromTorrance

One thing to consider is: If you wait too long to test your valves and they are out of spec but your warrantee will be up in a month the warrantee provider may decide to gamble that your engine won't blow up before you're out of warrantee and deny your claim.

Gary '09 C6

^ a very valid concern...start the appropriate inspection process with at least six months remaining warranty (for those that have warranty).

CTYANK2

Warranty on my 2006 Z expired in October. Thought about fixing heads/modding. Instead, traded the '06 for a 2011 Z and called Ken Fitchner for a great deal on a 6 year warranty. Didn't want to sell my car so I just bought a newer one same color. Now I have up to six more years worry free driving basically the same car.

olddragger

I am sorry but no you do not. A valve could possibly break and put you, your passenger and those around you at the time in danger. It is a small chance ...it depends on a lot of circumstances .....but it is a chance that is preventable. My point is...if something like that did happen... How would you live with yourself. Interstate speeds and crowding being what they are... I can see the possibility.
It's like driving any super performance car. You have to use common sense. Example...don't put underrated (speed)tires on it either.
Warrenties are great but they don't solve the entire issue. I rather fix a known weakness than getting insurance for it.

Gary '09 C6

along the lines of, "an ounce of prevention is worth a pound of cure."

CTYANK2

If you feel that strongly about protecting yourself and your passenger you should sell your Corvette and buy a larger vehicle.

LawrenceFromTorrance

It's really obvious that he was talking about everybody and everybody's passengers. I guess you would have every owner sell their car and get another, passing off GM's ignoring of a potentially dangerous situation as just fine. You are (for no good reason) a really loyal foot soldier in the GM army. Me I'm just into right and wrong and not blind loyalty.

olddragger

Ctyank....everyone has a choice. You stated yours and I respect that. I just was pointing out that there is more to this issue than just the car. You do not have worry free driving. Catastrophic engine failure in which the rod or something else can come through the block..spilling oil all over the road is not really that common anymore. Maybe people have forgotten or more likely have never experienced how easy it is to loose control of a car as a result.
I am amazed that this hasn't happen to someone yet. Or maybe it has and I am just not aware.
How about the cars that were identified has having a strong chance of erupting in flames when struck in the rear. Would anyone still drive one of those believing they were not going to get hit........or get it fixed?
The previous post was well said....oz of prevention is worth a pound of cure

CTYANK2

Olddragger responded to my comment "worry free" and he seemed to be referencing me. My response was specific to him. To be more clear obviously nothing is totally worry free.

Your comment saying that I would have "every owner" do anything is not what I said or intended to say.

Further your comments about me being a "...loyal foot soldier in the GM army" are inaccurate and I apologize if my post was not clear in that regard.

LawrenceFromTorrance

OK, I really was too harsh I apologize.

olddragger

Its no problem man---discussion is good. I know I have benefitted by being exposed to others opinions and them thinking of an angle or solution that had not occurred to me. Motor on and wish you the best.

important

Is there a summary/beginner's guide to the issue, how to diagnose and ultimately correct?

A cost estimate on each step would also be helpful.

I want a C6Z but this issue has got me concerned.

1972bluelt1

How many miles on stock heads?

CTYANK2

43,700 trouble free miles. No mods at all right down to stock air filter. A few track/autocross days and a few spirited street drives . Heads never checked. Had it on a Mustang dyno every year (April or May) and it made 460+hp consistently (typically 466 +/-). Other stock Z's dyno'd on same day were more like 450. Z was made in January 2006.

olddragger

One thing I wonder about ...and I am famous for wondering...is the minimal difference between a high milage ls7 valve guide wear versus the low milage one? Now this is just based on casual observation of people's posts of their milage and guides measurements
For example My engine has 70k miles on it and the guides were out of spec, but not any worse ( and actually better than some ) low milage ones. Why is that? What makes them stop wearing?
Why don't these engine use oil, why don't you see some exhaust smoke? Are the seals that good or is there just not enough oil getting to the spots that cause those symptoms. It is a lot to ponder about and a damn perplexing puzzle.