NachosZO6

Just a thought I had after watching the Wixom Tour video.

Since these engines are build by hand, could it be that an assembler was having a bad day or week or just a plain disgruntled employee and decided to do a minor change to the valves causing this problem on purpose? I mean, it could be that simple.

forg0tmypen

Did you count euro749 in the original 10 back in 09? Believe it or not, I own his car now. He sold it to another forum member and then I bought it from that guy. I actually was able to find his phone number on google (after 3 months of stalking) and spoke with him last night, he told me the first owner of the car was a young kid and ran it hard as hell and it snapped while on the freeway. Valve met up with a piston...

forg0tmypen

This is a real possibility that has to be taken into consideration with a handbuilt engine: human error. I will say this: it is highly unlikely everyone of the 27,000 Z06s produced was built and shipped out without any errors. Now why are they all valve failures? Who knows but as you see the milage listed in the list above, these failures are happening at relatively low miles, so that has to get you thinking: if it can happen at 10,000 miles then why haven't we seen hundreds and thousands of these, Z06s everywhere would be blowing up. Then, again, going by the list, you have no failures of 09 or newer Zs. What changes were made to the 09 or newer cars? Oiling system upgrade...food for thought.

LT5 John

Maybe with ALL those pain in the ***** asking questions Possibly annoying the builder and distracting them from what they do...

'06 Quicksilver Z06

No, I think I left him off.

I'll look him up though. Thanks.

NachosZO6

I'm telling you, it may not be too far fetched. lol

TORQJNKY

Ahh, the "Conspiracy Theory".

RFZ

on my c5 i had modded engine....had a set of ported heads which popped a tiny hole in the intake port and hydro-locked the engine bending a rod...the replacement bullet proof heads lasted about 3k miles when ALL of the valve springs took a dump.. the inner springs ate up the retainers and all the valves seals, then the springs broke. had two hand fulls of springs/retainers/seals in the oil pick up screen..put new set of factory springs/hardware and 30k later its still running strong..

bullet-proof heads...not possible...just like all the rest of the components failures happen...
another thing to condider is most people who mod continue modding/ changing parts for more power....i would like to see these so called bullet-proof heads with 30k miles on them...measure guide wear and see what they have...also will the shops who do the mods to the heads give you a 100k warranty ....me thinks not..

have stock ls7's had valve failures..sure...just like everyother component/ manufacturer have parts fail...something to worry about...well not to me...when i get in the vette its a happy time, not a darn if i start it a valve is gonna break time...

'06 Quicksilver Z06

......And, I'll say one thing.....that's a bullet proof post. Nothing wrong in that post.

TORQJNKY

Sounds like your so called 3K miles bulletproof heads were simply not put together correctly or there was some other issue (cam timing, wrong size valves or rods, severe geometry offset) that caused it. NO head breaks all the valve springs at the same time unless something is not right. Who put the heads together that broke after 3K miles?

hurleyg

this has me worried now, i have stock heads on my car with a lg x4 cam, for about 3,000 miles now, and no problems so far

Whats the average price if i send my heads off to get the valves upgraded?

NachosZO6

WCCH quoted me at $500 for the work. The problem for me is having someone R&R the heads for under $1k.

RFZ

i agree....incompatibility of the parts used to assemble the heads...a performance shop on the east side of the country did them...i found a pic , which helped refresh my memory what happened...the spring dampners dug into the retainers due to normal valve rotation...this in turn destroyed the seals , all the dampners and finally a spring broke... pulled the valve covers and couldn't believe the mess...pulled the pan, literrally had 2 hand fulls of debris in the oil screen...cleaned it up, installed factory ls6 valve springs and retainers ....still running strong 30k later...

the reason for the failure was the improper matching of parts used to assemble the heads..

i have been turning wrenches for a living for a long time ...modding for a long time... in my experience there is no such thing as bullet proof...all of the failures we hear of , no matter what make or model, have been occuring since the dawn of the auto...all things considered, the ls7 is an incredible power plant...its size, weight, power output, driveability,fuel economy and durabilty set the standard for high performance power plants... [ thats my .02 worth and probally not worth that]

it may turn out there is a problem with ls7 guide wear..[ beyond expected manufacturing failure rate]...personally i do not know any z06 owner who has had a major engine failure... i know they are there...best thing to do is to drive the car as much as possible... factory stands behind the power train for 5/100... after that its your baby, if you mod it its your baby..just drive them and enjoy!

TORQJNKY

Yeah, that is a mess. I guess for lack of a better word, I used "Bulletproof" when I started the thread. I guess "more reliable" would have been better suited.

I posted this over in the "Sky is falling" thread:

Would simply installing a roller rocker, significantly reduce valve side loading and valve guide wear? When you look at the flat side if a OEM rocker, you can always see abrasions across the valve contact point. A roller would have less surface area resting on the valve and roll over the valve vice slide against it when it pushed the valve down.

Thoughts? Is there a direct replacement roller rocker you could use without having to use a different length pushrod or taller valve covers?

forg0tmypen

I think so. I posted this a few days ago, I've been told by my local Corvette tuning shop (Fasterproms) that the use of yella terra rockers will decrease the valve side load on the guides. Now I'm still researching, but I wouldn't think the yella terra rockers would significantly alter the engine in any big way or make it any less reliable or add any extra stresses. Someone correct me if I'm wrong. Bronze valve guides are another similar mod that doesn't impact the tight knit system of the ls7 but can have a benefit of decreased guide wear. Seems like there are three solid preventative "mods" one can do: bronze guides, yella terra rockers and a better anti wear oil. I would think doing those three things to a stock ls7 would help greatly with this issue, if not entirely eliminate it.

TORQJNKY

I'm thinking that if you had your heads checked out and you didn't have any measureable valve guide wear, you could do the YT rockers and start using anti wear oil and probably be in a much better situation to prolong the life of your OEM guides and exhaust valves. I say don't replace the OEM valve guides right away only because Richard at WCCH prefers them over the bronze. I'm sure the OEM guides are fine if you have eliminated the valve side loading and improved lubrication.

Mopar Jimmy

1000% Very well said, no such thing as a bullet proof heads, PERIOD, sorry, sad but true gentleman.

forg0tmypen

Yes, of course I would keep my fingers crossed that my guides were all still in spec, that would be the news of the century. Then Id put in some YT roller rockers and change my oil and then drive the hell out of my car, with slightly less worry than the little bit I have

TORQJNKY

I agree that you can't make any cylinder head foolproof, idiotproof, "Bulletproof", call it what you want. But there is a hell of a lot you can do to at least make them less prone to failure. Let's call it "Bullet Resistant.

Sorry, sad but true, Mopar Jimmy

AzDave47

15-20 documented LS7 failures out of about 30K production is very small, not like the 150 M3's out of about 12K production 2001-3