Blackdevil77

So basically, there is nothing I can do to prevent this from happening without modifying the car and voiding the warranty? What happens if I just want to keep the car stock but want it to last a long time? S*** out of luck?

bambihunter

You could take the car to a GM shop, have them pull and break down the heads and render you a verdict. If you pass, you pay the labor charges. If you fail, they'll probably put you back in stock condition...in which case, you have rolled the dice and may crap out in a few thousand miles, anyway.

Your call.

bambihunter

87tign

Hey Guys,

This may be old news but I wanted to give a brief update on what I have found today just as an FYI.

I just called a well known Chevy dealer in Indianapolis (Ray Skillman Chevy of Indy) and they have had experience with this issue in the past. They said its rare but it does happen every so often. Their Corvette technician has been there for 16 years and the gentlemen in service was very easy to work with.

The service writer told me basically what I have read on this forum, there is currently a TSB out for the valve to guide clearance issue. It will cost me $590 for their technician to perform the "wiggle test" in the same way Hib on the forum has described it in his writeup. If there turns out to be no issue, I am liable for the measurement cost. If the measurements are out of spec, GM will eat the measurement cost as well as provide the replacement parts to fix the issue.

$590 to me is totally worth the peace of mind. I would much rather be proactive at this point than run it hard and potentially lose the engine which could end up with me or others hurt and it would seriously hurt the collectability of my Carbon Edition.

Just my $0.02. Hope this helps someone.

Thanks,
Andrew

Blackdevil77

Is there a certain mileage that is recommended to have this "wiggle" test done, or does it not matter and accumulated miles won't effect the results?

Vette @ 71

What would you do if the readings show to be in spec but close to the service limit of 0.0037 ?? How many miles on the car? New set of reworked heads go for about 2k..

87tign

Great question. As I understand it, the valve to guide clearance issue was due to a miss machining of valve guides and resulted in excessive clearance. I would imagine that a car with no miles could have a clearance problem but a car just on the edge of the servicability limit at 0 miles would go pasts the servicibility limit relatively quickly due to normal wear rates. It all depends on how fast these guides/valves wear and which ones made it onto your specific heads.

So to answer your question, I believe any car could have the issue at any time. You could measure a car at 0 miles and its fine and then measure the same car at 10k miles and its out.

87tign

Another great question. Honestly hadn't thought that far ahead and I'm not sure I could answer that question until I saw the measurements and knew how close all the valves were to being out. Of course, the wiggle test isn't a bulletproof test and there will be some error associated with it. Depending on how close they are, I would have to make a risk assessment. That being said, this car will not be on the track and will not be abused. I will drive it hard on the road when conditions are right but its mostly a crusing/fun car for me. I have other drag race/road race projects on the side that I like to rag on.

Currently, the car has a little over 5500 miles on it.

froggy47

So you know, there is a class action law suit on this issue (thread is on forum) and your guess is as good as anyone's how it will turn out and the time frame.

87tign

Awesome! Thanks for the heads up on this. Do I need to get my name added to a list to be part of it?

froggy47

Not sure, find the thread & post on it. They will tell you.

LS7Vet

08 here, second owner, 32k. Bone stock, very spirited driving when conditions permit: The Dragon, etc. I have GMPP, valves seem noisy but dealer says normal. Sadly I could spend another $2500 (what I paid for GMPP) and fix the issue GM declines to admit exists or just wait till she pops one day on a hard 2nd or 3rd gear pull; after reading this maybe it'll eat itself at Target.

Reality is I hate wasting money. Fixing a problem that GM says doesn't exist to only throw my unused $2500 warranty out the window seems like a waste. This engine will not make 75k despite being well cared for, but driven as intended.

Lastly, in the early 1900s this company called Allison made liquid cooled V-12 aircraft engines with "overhead cams." That may find it's way into a Corvette one day. How often do you hear about overhead cam setups dropping valves?

GubuZ06

For the vast majority of people who don't have a warranty would you approach a GM dealer for this fix or a trusted mechanic? Is this agreement from the IN dealer provided to you in writing? TIA. Great info on this thread. Being a recent new owner to an '08 Z and 2nd Z06 owner I'd like to resolve this issue quickly even if it's out of pocket now in hopes of reimbursement in the future or backdate a claim. Any thoughts?

sbrooks64

A trusted mechanic over the stealership. I wne twith AHP heads and haven't had a problem or worry since changing

MTPZ06

The problem here is that GM will just install the same crappy heads off the shelf from the parts dept....and that's if they are astute enough to identify if there is a problem. There are some good dealerships out there (Abel comes to mind), but sadly they are extremely few and far between.

dr_whigham

Guys, my service manager is asking for the TSB on this issue. I just bought an 09 and NOTHING has been done to it. I still have the master cylinder and low beam headlight recalls to take care of.

Can anyone please post the TSB?

Thanks!

SHM

This is what I found. Hope this helps:

#13-06-01-001:* Information on Customer Questions About Valve Guide Wear - (Jan 14, 2013)
Subject:* Information on Customer Questions About Valve Guide Wear
Models:* 2006-2013 Chevrolet Corvette 427, Corvette Z06 Equipped with 7.0L V8 Engine (RPO LS7)
--------------------------------------------------------------------------------
Customer Concern
Some owners of Corvettes equipped with the LS7 7.0L V8 engine may ask your dealership to check their vehicle for valve guide wear because of information that has been distributed on the internet, primarily at Corvette enthusiast sites. Due to these postings, some customers that have not had an issue may ask to have their vehicle checked. If a customer presents their vehicle and requests the valve guides be checked, the following information may be helpful to you and alleviate any concern for your customer.
Valve Guide Wear / Noise Concerns
To address any concern the customer may have, listen to the customer's request and ask the following questions to differentiate if the customer has experienced a correctable engine concern or has anxiety over information they may have read.
Important:* It is important to investigate all concerns and relay good factual information to your customer. If a customer indicates a concern about valve guide wear, it is possible they may have a valid unrelated engine issue, and do not know how to express the actual concern.
1 Have you experienced any concerns or difficulties that would indicate an engine problem?
2 Is the Check Engine Light ON? Does the vehicle exhibit any starting/running concerns?
3 If the concern is noise related, ask for a description of the type of noise heard?
Once the information is collected, and the nature of the customers concerns are known, here are some guidelines for appropriate actions:
• For any driveability, starting, running or found DTC code issues, if the car is under the respective warranty period, repair the vehicle following normal diagnostics as outlined in the Electronic Service Information (SI). If the vehicle is out of the warranty period, explain the available options for the customer.
• If the customer indicated a concern with engine noise, warm the vehicle to operating temperature and compare it to similar vehicles. If the vehicle does not exhibit unusual noises or malfunctions, the customer should be told there is nothing to indicate the need to disassemble the engine to determine valve guide wear. The LS7 is a high performance motor and as such is built with an emphasis on power while retaining the lowest possible noise and vibration characteristics. Some valve train noise may be evident, which is a by product of the performance nature of this engine. General Motors has reviewed paid warranty claims for valve and head replacement for the Corvette LS7 and the numbers of incidents are very low with no indication of an excessive wear issue.
• If the customer's sole concern is based on information collected over the internet, with no verifiable symptom, and the customer insists the engine be disassembled and verified, it should be explained to the customer that any charges for the inspection would be at the customers expense. Valve guides are an internal engine component subject to wear over the life of the vehicle. If there is excessive wear (beyond the indicated service limit) after the investigation is completed, GM will cover the inspection and repair expense for vehicles covered under the Powertrain Limited warranty.
Aftermarket Equipment and Valve Guide Wear
The use of performance engine modifications has been found to accelerate valve guide wear. Replacement aftermarket mechanical parts, or software calibrations, may adversely affect the wear of these and other components. Any modification to the engine of GM vehicles voids the powertrain coverage portion of the vehicle warranty. For additional information on GM policies regarding aftermarket equipment and calibrations, please refer to the GM Service Policy & Procedures Manual, article 1.4.14 (Voided Warranties and Branded Titles) and article 1.2.2.12 (Non-GM Parts & Equipment and Original Equipment Alterations), along with the latest versions of Corporate Bulletin numbers 09-00-89-016 and 09-06-04-026 for additional information.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
© Copyright General Motors Corporation. All Rights Reserved

dr_whigham

It does, tremendously. I'm also hoping for the one about using calipers rather than the "wiggle test."

SHM

Or, you can do what I did and do a oil analysis report at your next oil change. Mine came out great. less than 1 ppm of TI and other wearable metals were found in the oil. Although, I had one response which insisted the worn TI was going out of the exhaust and not into the oil. I've not seen anything using a caliper method as a TSB from GM. I've been trying to keep up with this. As I still have a PT warranty, I'm not going to worry about it too much at this point. If I would've seen copious amounts of TI or other related metals diluted in the oil test, then I'd be very worried.

MTPZ06

That may be fine for you because you have a warranty, but many do not. Outside of a warranty, no way in hell would I only use an oil analysis to keep an eye on a valve train issue that could cause a catastrophic failure. The wiggle test is not an expensive procedure to perform and determine if your heads need a much closer (more invasive) look. I hate to use the analogy; but you can go to the doctor for blood work, find that your PSA's are "normal", and still discover that you have prostate cancer.

bd4airman11

I worked with 50 Kenworth's (heavy haul trucks) and with every oil analyses senesce new, they still would suck a valve now and then.....
One oil lab check tells you nothing, as it takes at least 10 for any hope of tracking where the engine is for it's ware.....to little to late....check your valves! (07, 30,000 and every ex was WAY out)fixed and done!