exracer28

A friend asked me about getting the current "fix" done to his head and wanted to know if any of the shops that are modifying the heads/guides/valves provide any guarantee that the problem is really corrected. I told him I would post the question here but as far as I know there is not a guaranteed fix. I am a retired engineer and when we had a systemic issue there was a formal failure review board process that looked at all the possible contributing influences and provided the results and recommended corrective action to management. I do not expect a shop to perform this analysis and without GMs data it couldn't be accurately perform by an independent outside company. So the question is does any of the shops that advertise a "fix" actually guarantee their "fix" is the correct work? I did call a few places and the only response was we know what we are doing and we don't have any problems but would not commit to a guarantee that a valve issue would not happen again.

My advise to him was that if a shop does not warranty their work just buy a GM extended warranty and if it happens let GM replace the motor. Any better data I get will be passed on to my buddy.

LMB-Z

I'm sure that any shop is not going to warranty that their heads are "fixed". They will warranty that they are a good set of heads.

Unreal

There is a ton of reasons a valve can drop, or a motor fail. So what exactly would the shop be warranting? That the heads were built to spec, or are you expecting them to pay for a new motor when someone miss shifts, installs a cam with incorrect valve springs, doesn't maintain their valve train, runs crap gas/etc and chunks a piston, which knocks a valve off.

Other cars drop valves. My friends bone stock ZL1 with <6k miles dropped a valve in a movie theater parking lot.

So warrantying defects in their work/heads sure. Warrantying someones motor because someone did a valve job, that is a HUGE stretch.

Only way a possible warranty could work is if the shop installs/tunes/etc. That is how LPE/Hennesey do warranties. It is their package. You pay 2x as much, so basically prepaying for a failure.

Dan_the_C5_Man

Taking the "low road", e.g. any GM-related solution is best for those that have plenty of time and patience on their hands, because they will need it (fighting with warranty company, dealing with a failed motor on public streets or a race track, damage from being towed, potential damage from spining in your own oil, dealing with a dealership, waiting on parts, waiting on a replacement motor, fighting to get oil coolers, lines and tank replaced, potential damage from engine removal and installation, having the car sit outside at a dealership for weeks at a time, loss of use (but the monthly payment notes keep coming), paying for insurance on a vehicle you can't drive, potential failed transmission because they always seem to forget to refill it after engine re-installation, possible reduced resale value, possibility of dealing with the 12-13's and on main bearing and rod issues...

That's just off the top..

Or, spend $2K and dramatically reduce your risk of failure.

stefuel

In my opinion there is no "FIX" for the LS7 that doesn't include going back to design. There is only bandages. Some bandages are better then others. It will always be a high maintenance engine. First time I saw one with the valve covers off and I saw the offset rockers told me all I need to know

MTPZ06

Agree with Dan...while a warranty is a "nice to have"...its certainly not a pleasurable experience to go through a motor failure claim as we've seen in here on more than one occasion.

I'd rather do what I can to mitigate the possibility of a failure. If reliability/longevity is the primary concern of your friend OP, I'd advise them to fix the heads by having them rebuilt by a reputable LS shop, and stay with a stock cam. Too high of a lift cam causes unnecessary side-loading and leads to premature guide wear. Even on some "fixed" heads as we're beginning to see. The wipe pattern using stock rockers become less than ideal after about .630" lift. Stock cam is .591" IIRC.

I too wanted a "fix" that offered stock driveability, motor longevity, and better than stock reliability. I went with: AHP package 4 heads, MS90 guide upgrade, PSI 1511 beehives w/Ti retainers, Ferrea F2042p 1 piece hollow stem ex valves....stock cam. Proven parts, spintron tested...I feel I've done the best I could with mitigating a possible valvetrain induced catastrophic engine failure.

Gary '09 C6

good comments by all of the above...

...the only guarantees in life are death & taxes

rockinSeat

So is the word on the street not to even touch a 2012-2013 because of this? Sucks cuz I wanted a Centennial someday...

Josh B.

I wouldn't hesitate to mod a 11-13 MY like any other LS7. I think you are good to buy a centennial. Get a Z07 car though....

BigVette427

I believe most of those issues showed up very early on, sometimes with just hundreds of miles on the odometer as I remember reading some first-hand accounts.

The '13 427 'Vert market is amazing right now, there is one nearby with 47k miles on it and it's going for just about that many thousands of dollars. There are a handful of 427 'Verts nearby but they usually have double-digit tens of thousands of miles on them, it's actually rare to find one that hasn't been driven/enjoyed.

Even if you found a gem with just hundreds of miles it, find an aftermarket warranty or what not if it makes you feel better. I believe if it's got more than a couple of thousand miles on it, you should be okay as far as the main bearings and connecting rod issues are concerned. I have a 2012 Z06 that I bought a little over a year ago with 5k miles on it, and maybe 1,400 miles more on it as of today. I just ordered some heads from AHP and will swap them out soon, but I'm not really concerned by the main bearings or connecting rods at this point.

Tennispro1986

I am having my heads done in a couple weeks. The typical solution most people go with...heads machined, new bronze valve guides, stainless steel exhaust valves (some use the hollow ones for weight savings still), new springs and retainers.

Tp my understanding, and what seems like a ton of evidence backing this up, once this is done, there have been few to no valve issues after. I have asked quite a few shops and they both stated that after performing this work that it's pretty much bullet proof engine.

Now consider most people drop a cam in the car when having their heads done and are running the car highly modified and still not having the valve issue is even more peace of mine. I, on the other hand, am keeping the car completely stock. Not because I am afraid of a possible failure, but just because I never plan on racing it and the stock power level is more than enough for me.

Now think about how intense the forums are. You hear of EVERY dropped valve issue on the forums. We all know the internet will blow these things way out of proportion. Now of course we all know this issue is real, so I am not dismissing that. But if people were having issues after getting the heads done, and we know there are a ton of people on here with highly modified engines beating the **** out of them, you know we would seeing the "I dropped a valve and my heads were done" threads. I personally have never seen one.

I was detoured from buying a Z06 for a while because of the internet hype on this issue, but now I feel the fix is definitely good after doing my research.

Unreal

Disagree with it is more on forum. Go to a local performance shop and see all the cars they are constantly repairing from dropped valves, and at least here, that numbers blows what is posted on the forum away.

Ghost Knight

Yup. I personally know of several cars that it has happened to more than once (they put in stock motors which subsequently blew). When you ask the shops they have dropped valved LS7s come in all the time.

So much so that I parked my car until I got the heads fixed. Why risk a $10k build unnecessarily?

Michael_D

There is a correct way of doing things, and many wrong ways...... You having an engineering background know this well enough. What discipline anyway? The oil industry has treated me well troubleshooting and fixing broke stuff the past couple decades.

This engine is not so radically different than any other pushrod actuated, overhead valve V8; that there is any reason why standard practices won't work for it, just like the gazillion others around the world.....

I put this thread together a couple years ago, thinking it might provide some logic. I didn't.....

https://www.corvetteforum.com/forums...uide-wear.html

American Heritage

Glad you were not detoured forever off the Z06 because of the factory head/valve guide issue. Once you get it squared away the LS7 is a solid engine.

We have a slightly different approach to our reworks than the traditional bronze guide, heavy solid ss exh valves approach.

http://www.americanheritageperformance.com/
310-326-2399

cv67

anything can break.....a high lift cam esp if run at rpm will wear guides springs etc prematurely cant have it all.

exracer28

[QUOTE=Michael_D;1595142485]There is a correct way of doing things, and many wrong ways...... You having an engineering background know this well enough. What discipline anyway? The oil industry has treated me well troubleshooting and fixing broke stuff the past couple decades.

IT seems we have a similar engineering history as I started out as a EE but my primary skill set is to troubleshoot system problems and I have been very lucky working with some very intelligent people that taught me some very important things and the one thing that keeps coming back is without data everything is just an opinion. Without GM data on the heads the only thing left are opinions and guesses. I have decided to advise my friend just to extend the GMEPP for a few more years and by then either sell the car or relook at what may have been found out by the lawsuit that is currently in work.

I agree with your list of potential causes and sometimes we fail to realize the emission requirements GM has to meet. After deleting lead from our solder we have had many years of painful learning to get back to where we were before lead was banned. As you pointed out oil in the exhaust is a requirement that might have a negative impact on guide wear. Only time will prove if GM will release the engineering drawing and work instructions for the heads.

Thanks to all and we are going with GMEPP and this tread can be closed.

Craiger77

Agreed. Find a social media Z06 page. It's there also. Since the popularity of facebook, instagram, etc. owners have mitigate there and don't post forums as often but stories are still popping up.
Talk to shops Like RPM. They have seen numerous LS7 failures. If it was isolated like the 12-13 bearing I wouldnt worry about my 07' bearings. But the valve issues are across the board and even showing up in Camaro LS7's. The real question isnt if the problem exists, its if the head fix makes it go away.