LS7 Failures in the Z/28's How Many?

[JR'S Z/28 Texas]

Good Evening ALL! In the Z/28 LS7 how many engine failures are known? In Daily Drivers? Tracked Cars? Modified? Relating to Valve Train Problems? Other Problems? I know a lot of questions. I know the Z06-LS7 vette had some problems. Most was resolved in the LS7 of the Z/28. Just seeking some answers, For a New Potential Buyer that has a lot of concerns. Thanks JR

[Blueovalman]

What does the buyer intend to do with the vehicle? Overall goals? In my experience I have seen that overall the LS7 platform in the Z28 and Z06 is very solid and are impressive. If you do all of your required general maintenance on time they will last a long time to come. The positive note is the LS7 timing chain is revised and improved to be more durable in the newer Z28 version of the LS7. The only failures I know of were at the Showtime Speedway in Clearwater,FL. I seen a 2014 Z28 have LS7 lifter failure with only 10K miles. I also have seen a 2013 Z28 have differential and pinion failure with only 14K miles on a different occasion at the track. You have to pay to play.

[joelster]

The valvetrain failures of the LS7 engine were supposedly discovered and fixed in 2011 on the Z06.

[MX621]

Originally Posted by joelster

The valvetrain failures of the LS7 engine were supposedly discovered and fixed in 2011 on the Z06.

I’ve seen no info ( I’ve read just about everything there is to read ) sopporting this. There are several documented cases of 2011+ zo6 vettes with dropped valves. Look on the corvette forum. Also I’ve seen no evidence anything was corrected on the Z/28. If you think gm corrected the issue, your gambling with around 20k $ including labor if your not the wrench type. My plan is to do a full inspection once my warranty is out. I purchased this car well knowing I will most likely need to fix the heads after warranty is up. It’s a real issue, gm has 100% dropped the ball on.

[j o n]

Originally Posted by MX621

I’ve seen no info ( I’ve read just about everything there is to read ) sopporting this. There are several documented cases of 2011+ zo6 vettes with dropped valves. Look on the corvette forum. Also I’ve seen no evidence anything was corrected on the Z/28. If you think gm corrected the issue, your gambling with around 20k $ including labor if your not the wrench type. My plan is to do a full inspection once my warranty is out. I purchased this car well knowing I will most likely need to fix the heads after warranty is up. It’s a real issue, gm has 100% dropped the ball on.

+1 . Agreed

My warranty is up in 2021. We'll see what happens. If I'll still even own the car by that time? Will I want to allocate more funds towards the car? Will these cars' value drop, more so, with power-train warranty having ended?

Recent info on the LS7
https://gwatneyperformance.com/ls7-v...-need-to-know/

[4 FN 27]

Never heard back what the cause was. So I will not speculate aside from what I noted in my original Thread.

https://www.camaro5.com/forums/showthread.php?t=419077

[Supercup]

First - noted above is a 2013 Z/28 failure - maybe a typo on year, but no 2013 Z/28's.

On topic - valve and lifter issues are what plagued the Z06 - there are few documented cased of the same on the Z/28. Was there a fix after 2011 or not is much debated and no one knows for sure. But it is clear if you plan to track the car more than occasionally that it would be wise to upgrade the valve train to eliminate the risk once and for all.

Do a quick search and you will find this has been well documented. Here is a link to a thread that addresses your concerns in detail. There are links in this thread to multiple articles on the topic.

Link: https://www.camaro5.com/forums/showt...Z06+valvetrain

Otherwise the LS7 is known to be pretty much bullet proof! Very few documented cased of issues with LS7 in Z/28, linked to the issues noted in the thread and I have no concern at all with mine for the street or spirited driving. If track it more than a few times per year and it was not under warranty I would do the top end - which is my plan later this year when the warranty runs out.

Best of luck with your sale - your buyer should not have any real concerns - as you know the car is awesome!

[rcandiloro]

One way to mitigate the concern is to get a GM extended warranty. Peace of mind for the buyer......

[Blueovalman]

Originally Posted by Supercup

First - noted above is a 2013 Z/28 failure - maybe a typo on year, but no 2013 Z/28's.

On topic - valve and lifter issues are what plagued the Z06 - there are few documented cased of the same on the Z/28. Was there a fix after 2011 or not is much debated and no one knows for sure. But it is clear if you plan to track the car more than occasionally that it would be wise to upgrade the valve train to eliminate the risk once and for all.

Do a quick search and you will find this has been well documented. Here is a link to a thread that addresses your concerns in detail. There are links in this thread to multiple articles on the topic.

Link: https://www.camaro5.com/forums/showt...Z06+valvetrain

Otherwise the LS7 is known to be pretty much bullet proof! Very few documented cased of issues with LS7 in Z/28, linked to the issues noted in the thread and I have no concern at all with mine for the street or spirited driving. If track it more than a few times per year and it was not under warranty I would do the top end - which is my plan later this year when the warranty runs out.

Best of luck with your sale - your buyer should not have any real concerns - as you know the car is awesome!

Clerical error I meant to say 2015. Either way the valve dropping issues in the LS7 in the Z28 is not only documented but reality. From what I understand dropping valves in the LS7 can possibly happen rather if you drive your LS7 hard or not street duty or strip duty. I find quite a few people rebuilding their current LS7 cylinder heads or purchasing new LS7 cylinder heads even though the stock Geuine GM LS7 cylinder heads already flow excellent. Addressing the valvetrain earlier than later a specially the valves and lifters will cost you a catastrophic valvetrain failure and coin in the long run more times than not from what I have seen with the LS7. I still say the LS7 platform is a solid and great engine despite the minor set backs.

[sixty9fordkiller]

katech identified long ago that the culprit is the valve guides

[sixty9fordkiller]

this cat talks about it in this video

[joelster]

Originally Posted by MX621

I’ve seen no info ( I’ve read just about everything there is to read ) sopporting this. There are several documented cases of 2011+ zo6 vettes with dropped valves. Look on the corvette forum. Also I’ve seen no evidence anything was corrected on the Z/28. If you think gm corrected the issue, your gambling with around 20k $ including labor if your not the wrench type. My plan is to do a full inspection once my warranty is out. I purchased this car well knowing I will most likely need to fix the heads after warranty is up. It’s a real issue, gm has 100% dropped the ball on.

You read everything?

Originally Posted by Chevy Cust Svc View Post
Hello all,

LS7 Valve guide issue summary:
• Affects a small, number of '08, 09 ’10 and ’11 Z06’s
• GM discovered the condition through our cylinder head warranty data involving a very small percentage of our vehicles.
• Through inspection of returned heads, it was determined that a machining error in the valve guide had occurred at our head supplier.
• The quality issue has been contained as of Feb 2011 with 100% inspection of all heads.
• The most common customer complaint has been excessive valve train noise.
However if the condition is not addressed, it could result in engine failure. To date, where this condition has been observed, it has occurred early in the vehicle life.
What customers need to know: They should drive and enjoy their vehicles without fear. If their car demonstrates this condition, they are likely to hear unusual valvetrain noise first. If you have a concern regarding this issue on your personal vehicle feel free to contact me through private message on this forum and we will work to assist in resolving your concern. Feel free to contact me through Socialmedia@gm.com please put attention Evan in the subject. As always, vehicles that have modifications to the powertrain or the calibrations, are no longer covered by GM's warranty.

Sincerely,
Evan, Chevrolet Customer Service

]


Here's another little tidbit:

Originally Posted by jvp View Post
I had a chance to chat with one of the engineers at Carlisle about this specific issue. The discussion was fairly focused, and out of it I got the following points (paraphrasing, so forgive me here) ...
It sounds like it's affecting a reasonably small number of '09, '10, and '11 Z06s. It's not the cause of any issues that have popped up with the LS7 in prior MYs.
GM discovered the problem through their cylinder head warranty data; it went from nearly 0 to a peak of 6.5 problems per thousand engines.
They inspected the returned heads and found the machining error in the valve guide. It had occurred at their head supplier. As stated in the thread already: it's not a design issue.
Problems contained as of Feb '11 with 100% inspection of all heads.
The most common customer complaint has been excessive valve train noise and if left unattended, an engine failure would likely occur. A handful of engines have been replaced under warranty due to these specific failures.

Overall, the engineer wanted customers to: enjoy their cars! If a problem is going to happen, it'll be accompanied by a nasty/excessive valve train noise long before the engine fails. He didn't quantify what "excessive" valve train noise means, as opposed to the LS7's normal ticking.
jas

Came up in a quick search, took 10 seconds.

My car has 6600 miles and has been tracked a decent amount. No issues here.

[j o n]

Originally Posted by joelster

You read everything?

Here's another little tidbit:

Came up in a quick search, took 10 seconds.

My car has 6600 miles and has been tracked a decent amount. No issues here.

I believe MX621 was referencing 'reading' supporting evidence, outside of GM/Chevy, that supports the heads/guides were fixed.

GM/Chevy will always protect themselves and use their biased data and claims to sooth customers.

You need to consider the source of what information you're receiving.

[MX621]

Originally Posted by joelster

My car has 6600 miles and has been tracked a decent amount. No issues here.

ive seen/read all that. its been well documented on the CF that ls7's outside of the GM's problem window still have the valve/guide issue. even the LS9's have out of spec guide issues. you say no issues here.. have you had the guide/valve clearance checked? if your comfortable running your ls7 out of warranty on GM's word, that's fine and dandy. I'm not taking that gamble. my heads will be off next winter for a complete inspection and most likely rebuild. when the time comes I will certainly post my findings. I hope I'm wrong and every valve/guide will be in spec.