nuke61

You've already been told, but you seemingly don't want to believe the information supplied by several aftermarket companies, Katech among them, that show the failure rate to be significantly higher than GM was willing to admit.

You would rather take the word of GM over Katech, WCCH, AHP, etc.? The same GM that lied about ignition switch failures? The same GM that more recently lied about where the U.S. sold Cruze was built?

I had my heads measured after I had already purchased replacements (for H/C/I/E work) and there were 2 or 3 that were past the GM service limit - at 70K miles. If it's past the service limit, I say that's a failure. The fact that it didn't pop is just luck.

Tonylmiller

Which Z06 Facebook page? Could be some good information there. If I see a thousand dropped valves there, I will be changing my tune.

Tonylmiller

What Katech information? All I get is normally opinions, not real information.

Look, if some of you have an engine that is running fine and you call that an engine failure, we will just have to disagree about that. I'm talking about a catastrophic engine failure.
So most engines with 50,000 miles on them have nothing out of tolerance?

MTPZ06

https://www.corvetteforum.com/forums...post1594982862

nuke61

Information from several vendors, including Katech, that almost every engine they see has valve guides that fail to meet GM service standards. The place that built up my motor, for instance, suggested that I should not even bother having my guides checked until I was ready to do H/C/I/E work that I was going to have done in any case. Why? Because he said every LS7 that had gone through their shop had guides out of service spec.

Go look up GM lied and see how trustworthy they are before you decide you're simply going to believe GM and their BS 1% failure rate.

I had an LS6 with 100K miles on it, and when I sent it in for a 402 short block replacement, I was told there was nothing wrong with the original heads, and they were going to reuse them as-is, with new springs/retainers/pushrods, so yes, out of spec guides well before 100K miles is broken.

Mordeth

There is no reason to argue with certain people. We went through this entire process in another thread, which ended up being locked. The user is now intentionally derailing threads with nonsense. The OP did not ask his opinion on the merits of checking/repairing heads, but rather simply where to go, how to do it and how much it costs. I offered up this information in the first response, and now the entire thread has been hijacked by one misinformed user who is now intentionally trolling. I already placed him on ignore due to the other thread (makes the forum so much nicer) but unfortunately end up stuck seeing his posts when others quote him. I linked to him not once but twice in the other thread the Katech article, and now he asks "what Katech information?". This further shows he is intentionally trolling, and simply should be ignored.

Tonylmiller

Do me a favor and go read that Katech article. It does not say that the sky is falling.

In fact, it says they have NEVER SEEN AN ENGINE WITH A DROPPED VALVE.

The article states that it was a machining problem that was fixed. It also states that the exhaust valves are not a problem, yet many people replace them.

Tonylmiller

Seriously, I understand that a lot of valve guides are out of tolerance. Have I ever said that valve guides were not out of tolerance? And I understand that the vast majority of engines run many thousands of miles just fine with that condition. That is all I am saying. Owners should understand the information and make their own decision. Just do not go tell every new owner that they need to go spend $2,000 or more and get their heads fixed.

With that said, if you want to go spend $2,000 on your car for peace of mind, or to increase the power, I'm perfectly fine with that. Go spend $20,000 if you want.

Now some people feel that over 10% of LS7 engines (over 3,000 of them) have dropped a valve. I feel it is closer to 1%. I am still trying to gather information on this topic. At this point, their opinion is just as good as mine. Maybe better. I have just not seen the evidence (yet). If 10% of the engines have failed, it makes a lot more sense to proactively fix your heads, even if the car runs like a beast.

MTPZ06

^ On the contrary, you're reading the statement that GM made, which is captioned in that article. Katech is saying that it is NOT isolated to a handful of years, and it affects all years of LS7 production.

tekhombre

Your customer is very lucky and for sure avoided a catastrophic engine failure, we have experienced the worn guides or engine failures. Higher powers were looking out for him! Good catch.

Les

As always, right on point. Enough said.

2fastz06

https://www.facebook.com/Z06VetteOwners/

nuke61

I read it many months ago, while you weren't even aware of its existence

In it, Katech directly refutes what GM claims. GM has also been show to repeatedly lie about their products, yet you choose to believe GM over evidence to the contrary.

TXGS507

RamAir972003

Tony you have been here since 2006 and you still can't comprehend...now I know your not as intelligent as you say you are...please go watch discovery channel. You know Pluto is not a planet.

LMB-Z

Just for your DATA: there is no way in hell to tell exactly how many LS7 engine failures there has been. Not everyone who owns a 427 in ANY configuration, whether it is a Corvette, airplane, truck, or tank, is on this or any other forum. They do not all take their car to the same place for repairs. Some people still don't know anything about the LS7 engine problem (or lack of). You're stupidity just because there is not enough DATA is overwhelming. I personally do not know of anyone who has dropped a valve in their LS7, but on the same hand, I do not personally know anyone who has an LS7 (there are two in my city), but I have read of quite a few on this forum alone. How many???? I didn't count. But you simply don't have enough DATA to say that it is less than 1%. That is simply YOU'RE opinion based on the DATA that YOU have. Have a nice day.

Tonylmiller

Wow, I already know I'm stupid. I don't need you to tell me.

I was looking for opinions, and how many failures people are aware of. I have stated my opinion. I would like to know yours! Can we keep it civil and tone down the name calling?

My data that I'm using for my own opinion comes from failures that I have read about on this forum, and also information from Chevrolet, which is apparently suspect.

Tonylmiller

Wow, the people on this forum are so nice, especially when we disagree.

Tonylmiller

For the record, go back and read the thread. I was simply giving the OP an alternative opinion, which many people share, actually. Then Tech and the usual other suspects started calling names and piling on.
I know we don't agree on some things. Get over it. Doesn't mean one of us is right and the other is wrong. Doesn't even mean anyone is stupid! Truth may be somewhere in between.

Tech

I've shared ALL of this information with you multiple times. I even included NUMBERS in this thread which you so desperately need. You seem to only be here to argue, so I won't spend another ounce of effort to help you.

You can do the math to figure out how many more broken LS7 owners I'd have to meet that were too stubborn to have their heads checked and fixed (if OoS) proactively. It'll never happen.

Take my experience for what it's worth and aggregate it with other reports. Nobody is going to do that for you.