capevettes

Mine is an 06 I bought 2 1/2 years ago with no warranty and 2,500 miles on it. All stock except for Bullets. Almost 16,000 miles on it now. I have no spare LS7 in the garage, just a few Corvettes. I read everything and IMO the odds on a stock Z failing are low enough that I'm willing to take my chances. Maybe I just don't have the good sense to upgrade .

Everyone needs to do what they feel most comfortable with. IMO if you want to put big cams in and drive 1/4 mile at a time your odds of having issues are significantly increased. I'm just going to enjoy the car and not worry about it. Maybe ignorance is bliss

clogan

Cape: here's hoping that yours is one of the few good valve trains that last beyond 50,000 miles. My 2006, all stock, never raced, tracked only once, suffered failing guides at 38,000 miles. Here's hoping that when you double your current miles, your Z is still as tight as it is now. But I certainly would not bet on it. Odds are not in your favor. I strongly suggest that you at least be prudent enought to pull your spark plugs every 5,000 miles, and check for oily threads. That's a quick, easy way to tell whether disaster lies ahead. Oily threads were my first indication of trouble, and allowed me to R&R my heads before a catastrophe happened.
Good luck!

jwmgr8

I think its important for everyone to do what they feel is necessary to be confident in the health of their car, but some of you guys must have the best crystal ***** available, saying things like "failing Guides", "bullet proof", "disaster lies ahead", How do you know?
Unless it fails you don't know that it will- it might? but you don't know. GM has millions of hours of testing with their equipment and tens of thousands of installations yet so owners will rebuild their engines with parts that have been installed in 10 cars and have a total of a hundred hours of testing and they say they are now bullet proof?????
How about saying "tracked once but never raced"? what does that mean? tracked once ? is that one lap on a track, is it 500 laps pushing the car to the limit?????
I love the posts that say "another dropped valve"- yet when you dig into it - it is a highly modified engine that probably was beat to death. This creates such heart burn- when the post should say- Dropped valve in modified Engine. Then describe mods.
Please be accurate!
The forum can be such a great place to share ideas and experiences.

jedblanks

When you pull your valve covers and feel your guides and they are ok, then you can contribute. Otherwise you are just adding to the confusion. Data shows 50% will have worn guides (this has been discussed elsewhere).

Experience shows a worn guide with clearance at .0150 is approaching the real-world limit at which the valve head will break and destroy the engine.

It further follows at as a guide wears, the wear rate INCREASES. So a guide with .0100 will get to .0150 faster than it got from .050 to .0100 which happens faster than .0037 (service limit) to .0050.

Many of the cars failing are doing so about 20,000 miles.

My completely bone stock paper filter z with 16000 miles has 4 times the service limit on exhaust guide wear. Burns 0 oil, no smoke, no noise. Only this forum cause me to pull covers, rockers, springs and wiggle the valve. Until that point, I was just like everyone else who assumed it was tracked, abused, modified cars.

Now I know it is absolutely not limited to those cars.

spicytuna

That's true but despite their testing, it's obvious that they had a QC issue when it came to the machining of their heads. An issue which is vague at best (noisy engine), leads to engine failure and is limited to "a small number of 08's, 09's, 10's and 11's".

Based on the observations on this forum alone, the numbers are not small and they definitely aren't limited to 08's to 11's.

Not only were they understating the problem but they were telling their dealers to downplay the internet paranoia, despite hard data which proved otherwise.

If you can't trust them on their official statement, it makes you wonder what else they're hiding.

zcarbon

Same song & dance, If you're standing on it, Do the work first

jedblanks

We will have when it happens to you. It's been discussed that stoich conditions cause the most wear, and that is at lean cruise, not at 7k. "standing on it" didn't cause mine.

azZ06Mike

$4-5K to do Heads. I m getting in the Head business. Come on guys do some research. Doing the Heads is a 4-6 hour job at best. go to WCCH spend between $1200-$1600 on rework and then labor of $500.00 plus fluids your only talking max $2400.00. Wow it amazes me how many people do not get acts.

Fix your heads and keep the car!

jedblanks

If you subscribe to the theory that its just the guides, you can r&r for less than $700

If you do stainless exhaust valves and springs, maybe 1500 max

zcarbon

Sorry for your troubles, But GM never claimed building a 60K production race car....So, you're telling me, You've never streched it out, Truth! Right?

clogan

OK, JW, since you asked, my 2006 was tracked on one day, for 3 twenty minute sessions, with an instructor, at an HPDE at Barber. As a beginner, I was required to keep my speed down, and I did. That's the only time my car has ever visited a track. Prior to the head work, it had never seen redline, and had never seen WOT. Not even once. But it turns out my valve guides were shot.

Let me ask you this, JW, how do you know when to replace your tires? You monitor the wear, right? And then replace them when appropriate. It's the same with the LS7 heads. You need to monitor the wear of the guides, then repair/replace when appropriate. Saying that we Z06 owners with bad guides don't know for sure what lies ahead makes as much sense as saying that we don't know a blow out lies ahead if we never replace worn tires. So go ahead, drive your car indefinitely without replacing tires. I'm willing to bet you eventually have a failure. And if you ignore your valve guides, you eventually will have a failure as well. Unless of course, you are one of the lucky ones without the "Chinese" heads.

This issue is simple, guys: Valve guides on the LS7 are a wear item, and must be monitored and replaced as necessary...just like tires, oil, air filters, wiper blades...you name it.

Anyone who ignores this, does so at their own peril.

Just Cruise

I live in Lloydminster Alberta. Population 30 to 40thousand. We would like to move to Medicine Hat or Calgary since the weather is always usually 10 degrees warmer being only 3.5 hours away. Bigger citys both and cruise season could start earlier for me lol.

spicytuna

I'd imagine that there are no performance shops in Lloydminster, let alone a Chevy dealer?

Although I live in Canmore, I'm lucky to have left my Z06 in Toronto for the winter. There are shops out there which stock LS7 cores so they can work on them in advance and swap heads to minimize downtime.

A rework of the heads including labor costs around $2500 out there.

tigertank

hehehe he said headshop!!!lol

zcarbon

Tiger, Luv yeah! Gotta b an OG

jedblanks

I have never tracked the car. I have never had the car over 90 miles per hour. I have never been at redline for any period of time and held it there. I have never hit the rev limiter. Most shifts on the street are at 6k or less and that rarely happens. Just no opportunity. I May have hit 6k in 2nd once.

Seriously. No BS. This car was babied.

If you are predisposed to believe otherwise, to protect your false beliefs that there is no issue, I feel sorry for you.

I do not believe the guides are a wear item. They are right and don't wear, or they are wrong and do wear. GM got them wrong for the most part.

Just Cruise

Holy you live close to me cool. If you ever need an awesome tuner my buddy in Saskatoon saskatchewan i swear is the best. He is reasonable and tuned my buddy's Z06 better than Davenport in Calgary wich supposedly has the best rep in Alberta.

ATC399

Are there any Zs left that have not dropped a valve?

GMuffley

The vast majority.

z0sicktanner

Same powdred metal guides they have been using since 1997..I do agree bronze is better but I would replace the stock exhaust valve with ss.alot of 10 an 9 an 8 sec cars are using them with no issues and it's been proving it's self for over 50 years. I got almost 20k on mine and no wear at all.I have more vids an pics of worn an dropped valves since the last vid I did. not sure if i should post. I think most ppl got it now