2k Cobra

My car was never tracked, but caught the guide failure in time. If it wasn't for this forum, I might have a blown LS7.

MTPZ06

x2...I guess you and I are part of that very small but unlucky "10%".

xpimpindistressx

Cobra,

How much did you pay for your repairs? dealer or private shop? any insight you can give me and other members how to approach this issue?

thanks,

Gearpuller

olddragger

It is a confusing issue.
It seems simple but I have learned over my 66 yrs that things are usually not so simple.
This algorytmn is large.
To simplify I guess there are two questions?
Is there abnormal guide wear? Answer would be probably yes.
Does the valve guide wear cause a problem within the warranty period?......this is the one in which it does get confusing.

AZDANZ06

In my case my 2008 Z06 was out of warranty by time, not mileage. I think GM has been banking on the fact that many Corvette owners do not put a lot of miles on their cars and that this whole fiasco would just be swept under the rug as time passes by. Yes, there has been numerous examples of Z's with low mileage with worn out guides and have had heads replaced under factory warranty, this goes for blown engines as well.

clogan

I too was out of warranty by time. Dealer flat out said he couldn't (wouldn't) do anything for me. Isn't anybody honorable anymore? Certainly seems rare.

RamAir972003

Well here's how it went down my theory people that had warranty fixing to expire gm knew that the cars were either low mileage or fixing to expire, then bamm gm says it was a quality control issue that affects certain years....bs of course vetted do not get driven a lot especially those c6z so they said to hell with it people will pay out of pocket why recall and have a big law suit and issue.....think about really simple k own issue of course you have to drive cars to have the issue when people finally started realizing dropped valves were happening gm said only certain years are problematic its called improvising the situation. Till this day I feel so bad on how a large corporation that's America's icon can screw hard working people like us......i mean look at the c7z motors blowing up really nahh its a quality control issue....hand built motors by people who have done this for years know that the head issue is real here's money under table or loose your job severance package...

2k Cobra

I had an after market warranty. The heads and a T56 tranny problem was around $8,500. Work was done by the best dealer in the west, Abel. Because they used new GM heads, I didn't have any confidence in the repair. If I went aftermarket, the warranty on the engine was NFG.

Warranty was ending and they wanted $6,600 to extend it. Traded it in on a 13 GS. (Glad I did)

sam90lx

Subscribed. Love my new to me 12 Z07, head issues and all. This will be icing on the cake if GM's hand is forced to make whole to LS7 owners, past and present. Like others have said, probably some $30.00 check to all plaintiffs in the end unfortunately. Hope I'm wrong!

olddragger

Don't get me wrong. I too think GM is being irresponsible. But I have been involved in a very serious lawsuit against a major company before....won by the way...they settle, and I have first hand knowlege of the procedures.
GM's best defense is going to be that they had a warranty and outside that warranty they have no responsibility. If they loose it will set a precedent that warranties is general are not binding. That's a bigge that other companies are not going to want to see!
Maybe they can start rewording the warranty and exclude the time limit or increase it to 10 years...that would possibly satisfy both parties.
Mazda did this with the RX 8 rotary engine and it worked. That was a car ahead of its time... Great car

rled

This reminds me of the valve spring breakage issue on the c5 Z06. That was always in the back of my mind when I drove it. I never got around to replacing the valve springs. I sold it and bought a different sports car.

Vette @ 71

Sheesh, besides the video which clearly shows guide wear, all the other info proves NADA. If you can show by direct measurement the correlation between the wiggle as described in this post and bore guide measurements of the same guides, than you would have proof of the efficacy of the wiggle , short of this , you have NADA. Have you any correlation results to share??

Understand, I am not saying that abnormal guide wear is not a problem, I am saying using wiggle tests to demonstrate the degree , the width and depth of the problem fleet wise, is not a reliable indicator far tooo many variables involved..

You really believe Hib has sold his sole to GM??

Leon.

W.e at this point. It is literally going to take a few deaths before GM will even take a serious look at this issue. Even if something does come out of this, by that time, most people would have already fixed the heads or moved on. If i bought this car new and had to fix the heads, i would never buy a another GM product.

AZDANZ06

You are missing the point, using a dial indicator to test valve guide clearance (on the car or heads off the car) has been done for many years. On the car it is a test that indicates the degree of guide wear, if the measurements show it is at or past service limits, if so, then pull the heads. After the heads are off the car you can do all the back up measurements you want to satisfy yourself or compare to the dial indicator measurements. Valves are supposed to go straight up and down in the valve guide, not side to side correct? If you have side to side movement it obvious that there is excessive guide wear and that is not good. I have spoken with mechanics on this subject on other LS Motors, even at 100K miles they do not see very much if any side to side movement like we see with the LS7's.

Why does GM have the Dial Indicator Wiggle Test in the Corvette Shop Manual? This is not exclusive to Corvette's or GM, you know that right?

Yes, I do believe Hib is not a trustworthy person due to his relationship with GM. It appears you seem to think Hib walks on water

Vette @ 71

Sounds like you do not have any direct measurements that correlate the wiggle test results as described above to off the head bore guide measurements...The variables in the aforementioned wiggle test make it a very unreliable indicator of actual guide wear measurement. Hib demonstrated that in his well documented article, did you not read his article?

I would think vendors love it for obvious reasons.

Walk on water no, but I do have respect for Hib especially his support to this forum sharing his knowledge and in particular his effort
to take the time to document for forum members the correct methodology of performing a wiggle test the so called "test indicator". And yes we know he has a good relationship with GM and that is good for us. Not all GM folk are like their corporate deceivers..

To be clear:

1. I believe the wiggle test results as reported in the so called Pole are flawed and members should be so advised.

2. Pre-mature guide wear in some C6 Z06 is a fact, but depth and width is unknown.

3, Hib's well documented wiggle test indicator method is the gold standard for "wigglers".

AZDANZ06

This back and forth is tiresome, I have stated facts - you do not acknowledge what the automotive industry has been doing for many years. You just think Hib's way is the gold standard, well he is a Corvette Journalist, not a mechanic, machine shop owner, cylinder head rebuilder, etc. I think I am going to call the local newspaper and ask the Journalist that covers automotive topics what he thinks about all this and get back to you, that way we can compare two journalists opinions

Edit: I found his Bio online, looks like he worked for GM for quite awhile.

LawrenceFromTorrance

I have two Z06s and one self destructed via an exhaust valve and the other was measured out of spec. The new engine for one and new heads for the other were fixed under warrantee so I guess I'm in the 10% probability, oh wait that would put me in the 1% probability. Both were at low mileage but since this problem is so rare I don't need to worry any more. After all at this point it's in the 1/1000 or 1/10000 probability. I shouldn't even have to worry about checking the heads--- RIGHT

LFZ

Yes..you should definitely have them checked.

Vette @ 71

Quoting what others have said or done are not facts as it relates to the accuracy of the wiggle test measurement as a valid screen for guide wear absent the test indicator method..

If you would avail yourself of reading Hib's method you would have a better appreciation of it' s accuracy when one does not want to remove the heads..

Again I ask, do you have any data that shows wiggle test results correlate to actual bore scope measurements?