Z/28 Heads

[blessedhellride]

I recall that the Z06 had some engines fail due to valve train failure. Was this issue ever address or rectified for the Z/28 LS7 Heads.

[brahmabull]

I would also like to know as I had a C6 ZO6 myself but was never a victim of that horrible fate. Anyone else knw if this has been fixed?

[15Z]

+1 I would like to know as well. I just starting reading up on this topic last night.

[Fifedogg]

I don't trust them. If your going to stay stock who cares because you will have the warranty but if you plan on modding the car I would def get the heads done.

[2SSRS@Gen5diy]

If you over rev the motor you drop valves its a known fact, that was some of the issues not all of them but most, if you plan on turning past the red line you need a good head guy to set them up no 2 ways about it.

[johnr265]

What do they do to them when they "set them up?"

[2SSRS@Gen5diy]

The right valve guide clearance is one thing they will set up, but the right springs and seats to go with the cam you go with, but like the guy said if your staying stock your fine, you have a warranty.

[woodside783]

They did on the 06 z06 have issues but got mostly worked out

[MARKSTI]

Originally Posted by 2SSRS@Gen5diy

If you over rev the motor you drop valves its a known fact, that was some of the issues not all of them but most, if you plan on turning past the red line you need a good head guy to set them up no 2 ways about it.

Very true

I am doing alot of road racing with the car and spoke with many engine shops/builders

And the word on the street is that if plan on running the car on the track.. either leave the motor stock (if you reflash the car then the warranty goes bye bye) OR

Pull the heads and have then gone over with new valve train/guides/valves etc etc to make sure the valves dont drop...at a cost of $4-7k

The good thing is that with that done and a good cam/headers you could pickup 100HP+...so at least its not money down the drain

I guess you gotta go big or go home on this one
(505 hp ain't exactly peanuts tho)

I'm leaving my motor stock for now and putting money in the suspension/chasis/weight reduction

[blessedhellride]

Is this something that can be addressed with the lingenfelter 616 hp package

[MARKSTI]

FYI HENNESSEY claims that the z28 ls7 heads are revised and not gonna fail stock...the only one i have heard to say this.
However the engine package they sell (600 hp/actually 630hp) includes worked over clyinder heads...hehe

[blessedhellride]

Originally Posted by MARKSTI

FYI HENNESSEY claims that the z28 ls7 heads are revised and not gonna fail stock...the only one i have heard to say this.
However the engine package they sell (600 hp/actually 630hp) includes worked over clyinder heads...hehe

Thanks for the input guys.

[Dr Chill]

GM's official response on October 11, 2012:

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

[blessedhellride]

Originally Posted by Dr Chill

GM's official response on October 11, 2012:

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

Thanks Dr. Chill, this is great news!!!