'06 Quicksilver Z06

Tough break, but at least you have a good contingency plan already in place, and your confidence in that plan is justifiably strong as a result of the latest events.

Good luck.

yagrmiestr

2008, 21k miles, Engine factory stock
Got completely new heads covered by GMPP

1badtantrum

Add...
2009 Z06, 14300 miles, GM replaced heads

ctsv510

List updated, thanks guys

john_g_46

29 '06s
33 '07s
26 '08s
13 '09s
3 '10s
4 '11s &
1 '12 ....

I'm wondering if GM ever took any corrective action here to eliminate this machining problem.


John

Oskee

Add my 08Z to the list. New valves, heads, guides with 11k miles covered under warranty

Z06pete

Add my 07 Z to the list, New Heads, Valves, Lash caps, complete. Just out of the shop Friday. Like new again. 13k miles.

I forgot to say completely stock too! No mods what so ever!

Pete

Dirty Howie

Just amazing that so many cars can't make 15K miles on the stock OEM setup

Maybe the guides are just melting away from old age .........


DH

ctsv510

Already had you on there

rockinSeat

Don't throw tomatoes at me, but when exactly were all z06s outfitted with the ls9 style liquid oil cooler? Was it for the 2011 model year that z07s got it? Then all for 2012? Heh, I still can't believe taking 20 minutes of driving to just barely warm up the oil, over and over again, would not be able to wear off a few thousandths.

Looking at this data, there is obviously a big drop after 2009. But is that drop due to the really low number of zs sold that year and afterward?

ctsv510

Yes, at least partially.

The % of this list that each model year represents almost directly corresponds to the % of total production each model year represents.

rockinSeat

Ctsv10, the last car, "cgz06", should not be listed as a 2012 in my humble opinion. The car is a 2009 and should be listed there with an asterisk, noting that the replacement engine is supposedly a 2012. For the purpose of your thread, I'll give you two reasons: 1, who knows what year the heads were assembled vs what year the engine was built, and what inspection process the replacement engine go through vs. new cars off the assembly line? 2, I know there are some people out there that are curious whether improper oil temps are causing wear and that the ls9 liquid to oil cooler is the "fix". Since all 2012s got the ls9 cooler, it is incorrect to list a 2009 as a 2012, because it doesn't have the ls9 cooler. I find your thread to be the best data the forum has on guide wear, so thank you for maintaining it. I just feel it would be more correct to list cars under their model year. By moving cgz06, there are no 2012s or 2013s.

Now after reading about the replacement heads only having 400 miles when the guide "wear" was found, it really makes me doubt that it is wear and makes me think it is a manufacturing defect. I, for one, believe that there is a small number of cars out there that were truly mis-machined; but also, that most of us, over the longer term, will develop premature guide wear. I believe that cold oil temps, insufficient warmup, extremely long warmup times, and sometimes never warming up, will lead to premature engine wear, to include the guides. Lack of roller tip rockers, 1.8 arm ratio, high lift cam, hot sodium filled valves, etc don't help.

Thank you and let me know what you think about moving the listing.

Maligator

add me to the list, 09 6900 miles, stock, no track time.............garage queen..............

ctsv510

I hear your points, but I respectfully have to disagree. This one is certainly an uncommon case, but I believe build years of the motor and heads are more important to our research than the year of the car. If GM really did fix a machining issue at some point along the line it should show up in our list one way or another. The fact that this 2012 motor went in another model year car is not enough to dismiss the fact that a 2012 built motor exhibited the issue after only 400 miles. I have been contacted by no less than 3 members of this forum in regards to valve guides being out of spec in their LS7 that was installed in another model car completely. (Not a Corvette and no oil cooler). I chose to not include them for purposes of this list because I feel it introduces too many other variables. In hindsight perhaps I could have added an additional section to the list for these cars.

In my research and experience, the engine build dates match the casting year of the heads attached to them. CGZ06 had confirmed the build date of the motor to be in September 2012 so signs point to the heads being cast and assembled in the same year. Because of this, and without evidence to the contrary, I have to stick with what the past has shown to be true - heads cast and assembled the same year as the motor being built.

I know moving this listing would align with the oil / cooler theories of contributing to the valve guide wear, but objectively this car belongs in the 2012 section. The fact that it was a 2012 build date motor with guides out of spec at only 400 miles to me says that there was no way the oil cooling issue could have been a culprit in this case, and it is a matter of bad machining off the bat.

We also don't know where CGZ06 lives and what the outside temperatures were like in the 400 miles that the new motor was driven. It may have been Maine in the winter, or it could have been southern Florida in the summer.

That being said, if more people think that it should be moved for your reasons then I would reconsider.

71'AirStrike

71'Airstrike 2009 z06 36,000 miles 2 exhaust valves seriously out of spec.
bone stock at the time if measuring

Turbotank

I'm measuring two 06's (one with 69K the other with 24K) this weekend and will report back. Ive got another 2 06's both with under 20K on them to test the following weekend.

Im halfway hoping mine are out of spec as that would force me to jump on a H/C setup

ctsv510

I'd like to hear the results, but for purposes of this list I am conflicted on adding non-members to the list. Since there is no control on the possibility of having cars listed more than once inadvertently and not being able to confirm the individual identity of each car, adding these out of spec examples will undoubtedly lead to accusations of padding the list and recording invalid or invalidated data by those that believe that the issue is overblown and non existent in the world outside this forum.

So unless we can attach each car to a forum member who owns it, I'm afraid we can't include those results in the list.

Your car, of course, once it is measured would be eligible.

rsalco

Please remove my car from the list ['11 model yr.]. Subsequent dealer inspection suggests first 'wiggle test' suspect. Since it has warranty thru '16, I'm just going to run it 'til it breaks. Or doesn't.

ctsv510

I can remove you but can you clarify what you are saying?

You had a wiggle test done by ____________ that came back out of spec.

Subsequently you had a dealer inspect the guides using ___________ method and they are reporting that your guides are in fact in spec.

rsalco

Yes and yes.