Mopar Jimmy

For those looking to modify their LS7 heads I really don't see how much more clearer it can be stated than this! Here is your fix if you want to redo your heads, coming from the one company who has more experience than any other company when it comes to BUILDING and PROFESSIONALLY RACING Corvettes and these ENGINES for Corvette Racing (or just a street driven heads/cam LS7)!!!!!!

Also, Jason provides great info above as to what the warning signs are if you think your Z is going to have an issue, thanks Jason.

LS9Drew

The ti/mo valves are super expensive though over 1200$ that's almost more than the head work itself. Specially when we haven't seen failures.

Admiral Ballsy

Yes. I'm a little amused that part of the approved solution to exhaust valve guide wear is replacement of intake valves.

Undy

If the OEM intakes aren't compatable with the bronze guides then why not sintered iron guides for the OEM intakes and silicone bronze for the exhaust??

hoefi

So, I take this as Katech is officially saying that THERE IS A PROBLEM.

The important thing is not what Katech can do to solve the problem. It's what GM can do to solve the problem. Give a customer the same engine after the first one is blown is a joke. Eventually, the customer runs out of warranty, then what happens. Everyone lines up outside Katech after their warranty is out with their credit cards in hand?

GMuffley

Thank you.

Les

Thanks, that helps. Anxiously awaiting your update.

forg0tmypen

Thanks for commenting Jason. Too much uncertainty to move to SS valves. What people who accuse you of covering for GM don't realize is you build engines with the same oem exhaust valves. AND put a warranty behind it.

FrankTank

thank you for posting . It will be nice to see you're findings so we can finally put this to rest .

Random84

Have there been ANY intake valve issues with production Z's?

ConfusedGarage

Yes, there have been intake failures as well, just less of them.

I'm sort of surprised that some above drive a car at this price point but balk at the cost of Ti/Mo valves. They are a little pricey I guess. However, I would think if you're really set on not spending much, maybe only have bronze guides pressed into your exhaust valves and replace those valves with OEM units. Not sure if there is a downside to this, but I just did it all with bronze, OEM exhaust and katech Ti/Mo intakes. I drive my car hard and don't think about it anymore, well worth a few grand to me. To each their own.

'06 Quicksilver Z06

If I'm reading you right, then it's sounding like the valve guides were the problem, and going from the powdered steel valve guides to the bronze valve guides is the way to go.

However in doing that, then keep the stock exhaust valves, but change the intake valves to ti/mo coated.

So was it the valve guides which were causing the exhaust valves to fail?

I ask that question because you're not saying throw out the exhaust valves themselves, but you are saying throw out the stock (exhaust) valve guides (as well as the stock intake valve guides)and go from there.

This all would imply that there was a problem with some bad guides.

Also with regard to the part in bold above, would you please clarify:

"The proper fix if the vehicle is out of warranty or modified is bronze guides with Ti/Mo intake valves and OEM exhaust valves such as Katech has been doing all along."

Is this also the proper fix for a car which is still in warranty????

FSTFRC

Thanks Jason! Someone should make this post a sticky! (not the whole thread)

Mopar Jimmy

EXACTLY, Hello, is ANYONE home!!!!!

But that is what fear and paranoia does to a person!

TARANTULA

Thanks for your help Jason. My question is how can we explain (demonstrate)to a dealer that the car has excessive valve train noise when all they do is say its normal.

20psirabbit

I didn't know that, but that's good to know. And for what it's worth Jason, my post wasn't meant as an assault against Katech. I'm not looking to point a finger at anyone or to throw anyone under a bus. I'm just a concerned owner doing the best I can to sort through the various opinions and data, hoping to come to a solution that doesn't involve me replacing a motor, that's all. My '06 Z has 24k on it, I'm just hoping to hear that there's a concrete solution to this situation. I don't disbelieve Jason or anyone else. I just want to make sure when I tear the car apart it gets done right, not repaired with a band-aid. It makes me a little nervous that waiting could potentially cost me a lot of money, or nothing at all. So if anything, take my posts regarding this subject as a concerned owner that admittedly knows nothing about this, not a guy that claims to know more than anyone.

JetBlue427

ok so the two questions i have is...what is WCCH doing for the intake valves? cause there using bronze guides
and who does Katechs heads? If i went to Katech do they rebuild them there or send them out?

JetBlue427

I have wondered that myself....does anyone have a sound clip of a bad valve train? mine seems quiet while driving...other then what i assume is a small injector noise coming into the cabin

Katech_Zach

I've posted about intake guide wear before.

That is an option.

Nothing changed. I've been saying to replace the guides with bronze all along.

Sure, you can do the bronze guides if you're in warranty, but GM won't pay for aftermarket parts on a warranty. You would be on your own in that case.

Soon you will have a way to do this.

WCCH has been polishing the stock intake valves. We say improvement when doing this, but not to the standards we were looking for.

WCCH has been doing Katech's heads as dictated by us with bronze guides and Ti/Mo intake valves.

Chalky

Jason, appreciate you staying involved and sharing your findings. Just curious but do you know why this is only affecting a small number of engines and not all of them?

Any idea why GM changed part # for 2009 and later exhaust valves?