tim414

I have found MORE evidence this is a widespread issue, not only those cars in warranty that the thread up top mentions, but rather extends to all LS7's.
I have been a life long GM new vehicle buyer including the Chevorlet (obviously), GMC products and caddy.

I am ANGERED and if GM does not handle this properly, they have lost a life long customer. I WILL GO beyond that as well.

I expect that GM better come up with a dealer name that can handle this. I am expecting a certified high skilled tech to "tear-down" this freckin 2010 engine of mine.

It angers me because I have wanted a 427 Vette a LONG time.

You 427 Vert buyer BEWARE. You have have this same freaking engine too.

I have been intentionally putting off GM customer service while I did my own research locally in DFW area. THIS IS A ISSUE with "most" all of these freaking engines.

Signed,

ANGRY Lifelong NEW GM" car/SUV/Pickup Truck buyer.

ADD: the thread up to ONLY mentions Z06's IN WARRANTY. This GOES BEYOND WARRANTIED Z06's

'06 Quicksilver Z06

I found evidence of the same thing. Some of what I found, I can't say on this forum because the owners of the cars don't want their names out here.

But yes, I found evidence of same. This is what I've tried to get across to Random, "Paul" and others.

People think I "flip flopped" on this issue out of the clear blue????

No sir. I saw something. I found something. And from your tone above, it was the same thing you found.

john_g_46

It has become crystal clear to me that this is indeed a chronic problem for all LS7s. I had my doubts up until I learned the guides were shot in my 2007 which has been mostly babied its entire life.

http://forums.corvetteforum.com/c6-z...st-mortem.html

Pull your plugs and check them for oil. It's easy to do. That's what put me onto my badly worn out guides.



John

Johnjan

Sooo, your 2010 427 blew up?

TurdsOfMayhem

What's the "more" evidence found?

Silver05GTO

Imagine if airlines used this mentality when discovering "cracks" in wings (the new Airbus A380 comes to mind)

Well if your plane didn't fall out of the sky, then why be worried of a widespread issue????

The evidence of guide wear is stacked, it's evolved over time and confirmed to be a real issue. The LS7 has a *fatal* flaw, it will destroy the engine and result in a 15k+ out of pocket expense when it rears it's ugly head if your out of warranty.

Up to the individual on how he/she will handle this. Sticking you head in the sand doesn't change the fact the heads are a weak point in an overall solid and reliable car.....a 15k dollar weak point.

FSTFRC

Random84

I appreciate your efforts in the past, and I understand why you changed your position - this isn't about me vs you as personality differences are irrelevant.

People say it extends to "all LS7s" and you don't take issue with it? That statement implies that "every car" is therefore going to have an issue. We know this isn't the case - there is statistical risk for sure, but known guides/failures/issues combined only amounts to a few hundred cars.

The whole situation is definitely alarming, but again without contributing to the hysteria (and without mentioning names): what is the approximate total of every bad guide or busted valve that you've heard about, read about or otherwise talked about?

What IS this evidence of widespread failure affecting ALL LS7's that three of you are referring to? Is it top secret?

I ask because I'd like to get back into a Z06 someday, and I'd like to know as much about the issue as possible to plan my corrective action too! Knowing how widespread the issue may or may not be might help steer us towards the actual cause: poor quality control on a few guides out of thousands? inherent defect in valve manufacturing that will take down every car out there? Head geometry that would require complete aftermarket replacements? Kind of a big spectrum - that not all of you agree consistently on - and of course at the end of the day we're really kind of speculating on what the most likely causes (and fixes) are and going from there...

This is what I've tried to get across to Quicksilver, "Chad" and others. But they think I'm denying the issue altogether versus looking for more factual information on our risks and weighting that against what path to take. Of course I don't know what this new information you're referring to is, but the best I can gander is that the risk is around 2% of all cars - maybe up to 5% if I am really cynical?

What numbers are you guys coming up with, given your access and recent revelations?

Iceman427

How do you explain Z06's that have high mileage and no issues? You can't. This issue DOES NOT occur in ALL 427's.

DON T.

What he said...

agentf1

I agree, GM should warranty any 427's that have an issue related to valve guide issues regardless of age and mileage (within reason).

If I have an issue and GM does not stand behind it you can believe it will be my last GM car I ever buy as well. I am hoping this is a bridge I will never have to cross. :-(

JetBlue427

Ok so the original list was topping out at about 50 or so motors...are you telling me that a crazy amount of people PM`d you to add to that list? I know the reasons why some people dont want to discuss a blown motor...but after its replaced I dont see a reason not to talk about it. I have met one very popular forum member who dropped a valve a few years back but its never been discussed for obvious reasons. But how many extra dropped valve cases made you flip flop?

Bill Dearborn

The answer to your question is we really don't know since from my knowledge a high percentage of the failures have been covered by GM and we only know the engine failed and not why on several of those. Then there are the unreported failures. There are at least 5 failures that I know of that were not reported on the forum as the people do not participate on the forum.

So there are some things you need to think about. We know that all LS7s will fail at some point in time as does anything else made by man. The question is how soon and by what mechanism? As I have mentioned many times before I come about this from the perspective that I personally know a number of people who had an identical failure to mine. Some happened a couple of years before my engine failed and others have happened up to a year after mine failed. The cars were all 07s and 08s. The other day I posted another copy of the Youtube in car video showing when and where my engine failed and a day later I had an email from another person telling me that in a weird coincidence his engine failed in almost the exact same spot on the track. In my world the vast majority of LS7s owned by people I know have failed from valve drop. That definitely gives me pause since the cars came from random places around the country. Some were bought new and others were bought used with varying amounts of mileage on them. The people owning these cars are scattered across NY State and Canada and we only associate when we are at the track. In 09 3 of us were at a July event with our C5s and 3 weeks later were at another event with C6Zs and surprised each other since we separately decided to move up on the spur of the moment for a bunch of different reasons. All 3 of those engines failed within the next 3 years. At the time I made my purchase I already knew of 3 other people whose engines had failed but didn't think much about it. The next year one those people had a second engine fail on his new Z06. Then I ran into 2 other people at the track who had engine failures during the event. From my perspective each of us was playing Russian Roulette with at least 5 bullets in the 6 chambers.

Since you want to go back into a Z06 you have a choice: Get yourself a Z06 that has had a number of miles put on the engine and before driving it have the heads inspected and guide wear measured at a dealership. They can do that for about $1K. If the heads are in need of servicing then you can see what GM might do for you even if the car is out of warranty. Or don't buy one.

By the way the C7 LT1 is going to use the same type of exhaust valve.

Bill

Admiral Ballsy

They don't have any issues. Until they do.

How many high-mileage cars have had their heads pulled and valves checked? Of those, how many were in spec?

In fact, how many cars whose guides have been measured regardless of mileage were in spec?

If my car is running great at 85K, but has severely worn guides, by your definition do I have an issue?

EvilZ51

That's my big question.

john_g_46

My car was running well at 88,000...and my guides were shot.

http://forums.corvetteforum.com/c6-z...st-mortem.html

Pull your plugs and look at them. Best to do after sitting over night or over the weekend. If they're oily, your guides are probably shot.



John

avalonandl

Were all the LS7 heads all machined and assembled by the same supplier? I doubt they were machined in-house. Due to the number of failures but the lack of an overall recall I will put forth the following" theory":

Hypothetically if the machining was done by more than one vendor than this may be the case of one vendor supplying "out of spec" parts. In this day and age in the auto industry inspection at the end use plant is very often done on a spot basis at best. Suppliers become approved- submit their GP3 samples and everybody is happy.

It is also possible a particular machine to become out of spec in the machining process, or tooling to get out of spec and not be caught for a while also.

Avalon

'06 Quicksilver Z06

Depends what you mean by a "crazy amount".

Resale, a blown motor gives the indication that the car was beat and other things might be next to go. Transmission. Differential.

A car with the original engine in it, is typically more desirable than one which has had to have it's engine replaced.

Previous position on this issue and embarrassment after being vocal on it, only to later suffer a failure. Moved to another car, left the forum. Court proccedings which cannot be discussed, are a few of the other reasons some might not want to talk about it.

I think I know who you're talking about.

But what "obvious reasons" are you referring to, or offering up, as to why there was, or is, no discussion about it?

About eight that are "unreported". Along with continued reports all along the way which were openly posted in here, plus the experiences of shops I spoke with when I was at the height of researching these instances and keeping the lists. One particular instance I recall was in an instance where I was buying a set of wheels, and the shop owner remarked that he had just gotten in another Z06 "that ate a valve".

This was curious as I never even inquired. He volunteered it. This was at least 3 years ago, and coming from a guy who was not active in these forum discussions.

What I have discovered though, is that you will have to go off this forum in order to get anything close to an accurate or full perspective of this.

Those who really want to know, I encourage you to do that.

Talk to some of the shops, not just one or two of them. Talk to shops nationwide. Ask them what they are seeing.

Ask Charlie at RPM, TJ Wong what they see.

Talk to some of the cylinder head people Richard at WCCH, Darin Morgan at Darin Morgan Cylinder heads, and others. Ask them what they're seeing. These are people who know cylinder heads inside and out.

Talk to some of the machine shops who do head work in your area and surrounding areas.

If you really want to get a full perspective of what is going on here, well then you owe it to yourself to hear from more than just one shop which says basically that all is well.

It's not easy. You'll have to make some phone calls and send some emails.

But what you will find, is more information on this topic than just that which shows up on this forum.

VicCaerter

I can't say for certain, but my #4 exhaust valve had enough wobble to cause a click when moving the stem side-to-side without a spring on it. The plug also had a significant amount of oil on the threads. This was at ~27k on an 08. I traded her 2 weeks ago.

BTW, its currently for sale at a Nissan dealer in Rochester, New York, 1G1YY25EX85115238.

bearcatt

Sometimes I think the extreme 1.8 rocker arm ratio, imperfect wipe pattern in some cases, excessive heat on the valve guides might be suspects.

Maybe pulling the heads every so many thousands of miles for a freshening up is something that might need to be done in maintenance intervals.

Low mileage LS7's and LS9's that have failed, might be the ones with defective exhaust valves or head machining.


Boy am I reaching.




.